SCIENTIFIC TEMPER AND SOCIETY: जून 2025

Editorial
www.thelancet.com Vol 373 May 16, 2009 1659
A Commission on climate change
“Climate change is the biggest global health threat of
the 21st century.” This statement opens and sums up
the final report of a year-long Commission held jointly
between The Lancet and University College London
(UCL) Institute for Global Health. Climate change will
have its greatest impact on those who are already
the poorest in the world: it will deepen inequities and
the effects of global warming will shape the future of
health among all peoples. Yet this message has failed to
penetrate most public discussion about climate change.
And health professionals have barely begun to engage
with an issue that should be a major focal point for their
research, preparedness planning, and advocacy (the UK’s
Climate and Health Council is a notable exception).
The most serious threats facing human health today are
deeply complex. They include economic crises, pandemics,
poverty, and violence and conflict. These problems will
demand complex solutions. But few organisations are
able to bridge the widely differing domains and disciplines
necessary to define ways to solve these unusually
challenging human predicaments. Universities are such
institutions. Strangely, they are commonly neglected
sources—and forces—for social change. Even within
many great universities, there has been a withering
of ambition, an erosion of confidence, about their
contribution to society and its ills. But since The Lancet
began its global health series (with child survival in 2003),
we have observed the remarkable wealth of knowledge
and skill within truly great educational and research
establishments. Universities with a strong social and
moral vision have huge potential to assist policy making
in health. The challenge is to harness these possibilities
of influence to address neglected but serious threats to
human—even planetary—survival.
UCL is a university that has combined a distinguished
history of moral engagement with a more recent
revitalised global purpose, expressed through its
strengthened commitment to global health in teaching,
research, and institution building. In preparing to
undertake its work for this first Lancet Commission, the
UCL team, led by Anthony Costello, reached out beyond
health to engineers, political scientists, lawyers, geographers,
anthropologists, economists, philosophers,
and students, among others. They discovered new ways
to review evidence and integrate ideas collaboratively.
And through these efforts, they identified five critical
challenges that scientists, clinicians, and policy makers
will have to address if climate change is not to become
the biggest catastrophe threatening human survival.
First, there is a massive gap in information, an
astonishing lack of knowledge about how we should
respond to the negative health effects of climate
change. Second, since the effects of climate change will
hit the poor hardest, we have an immense task before
us to address the inadequacies of health systems to
protect people in countries most at risk. Third, there
is a technology challenge. Technologies do have the
potential to help us adapt to changes in climate. But
these technologies have to be developed out of greater
research investments into climate change science, better
understanding about how to deliver those technologies in
the field, and a more complete appreciation of the social
and cultural dimensions into which those technologies
might be implanted. A fourth challenge is political:
creating the conditions for low-carbon living. And finally
there is the question of how we adapt our institutions to
make climate change the priority it needs to be.
The Commission calls for a new public health
advocacy movement. This movement has to usher in
an unprecedented era of cooperation between widely
divergent, but utterly connected, spheres—disease,
food, water and sanitation, shelter and settlements,
extreme events, and population and migration.
Health professionals are critical to this movement. Too
many doctors have been silent for too long about the
importance of climate change to the future of health and
health services. Fortunately, in the UK, the Royal College
of Physicians has given a uniquely strong professional
lead. Its commitment needs to be reflected in the work of
other professional bodies and associations worldwide.
The Lancet is planning an extensive programme of
work to address other neglected areas in health that
demand a complex interdisciplinary analysis and
response. We see universities as indispensable partners
in this effort to translate science into practice and policy.
Our commitment is long term. With UCL and other
partners, we plan to convene an international summit
in two years’ time to review progress and priorities in
our collective responses to the urgent and alarming
health effects of climate change. ■ The Lancet
See Comment page 1663
See Perspectives page 1669
See The Lancet Commissions
page 1693
Science Photo Library
The Lancet Commissions
www.thelancet.com Vol 373 May 16, 2009 1693
Anthony Costello, Mustafa Abbas, Adriana Allen, Sarah Ball, Sarah Bell, Richard Bellamy, Sharon Friel, Nora Groce, Anne Johnson, Maria Kett,
Maria Lee, Caren Levy, Mark Maslin, David McCoy, Bill McGuire, Hugh Montgomery, David Napier, Christina Pagel, Jinesh Patel, Jose Antonio
Puppim de Oliveira, Nanneke Redclift, Hannah Rees, Daniel Rogger, Joanne Scott, Judith Stephenson, John Twigg, Jonathan Wolff, Craig Patterson*
Executive summary
Climate change is the biggest global health threat of
the 21st century
Effects of climate change on health will affect most
populations in the next decades and put the lives and
wellbeing of billions of people at increased risk. During
this century, earth’s average surface temperature rises are
likely to exceed the safe threshold of 2°C above
preindustrial average temperature. Rises will be greater at
higher latitudes, with medium-risk scenarios predicting
2–3°C rises by 2090 and 4–5°C rises in northern Canada,
Greenland, and Siberia. In this report, we have outlined
the major threats—both direct and indirect—to global
health from climate change through changing patterns of
disease, water and food insecurity, vulnerable shelter and
human settlements, extreme climatic events, and
population growth and migration. Although vector-borne
diseases will expand their reach and death tolls, especially
among elderly people, will increase because of heatwaves,
the indirect effects of climate change on water, food
security, and extreme climatic events are likely to have the
biggest effect on global health.
A new advocacy and public health movement is needed
urgently to bring together governments, international
agencies, non-governmental organisations (NGOs), communities,
and academics from all disciplines to adapt to
the effects of climate change on health. Any adaptation
should sit alongside the need for primary mitigation:
reduction in greenhouse gas emissions, and the need to
increase carbon biosequestration through reforestation
and improved agricultural practices. The recognition by
governments and electorates that climate change has
enormous health implications should assist the advocacy
and political change needed to tackle both mitigation and
adaptation.
Management of the health effects of climate change
will require inputs from all sectors of government and
civil society, collaboration between many academic
disciplines, and new ways of international cooperation
that have hitherto eluded us. Involvement of local
communities in monitoring, discussing, advocating,
and assisting with the process of adaptation will be
crucial. An integrated and multidisciplinary approach to
reduce the adverse health effects of climate change
requires at least three levels of action. First, policies
must be adopted to reduce carbon emissions and to
increase carbon biosequestration, and thereby slow
down global warming and eventually stabilise
temperatures. Second, action should be taken on the
events linking climate change to disease. Third,
appropriate public health systems should be put into
place to deal with adverse outcomes.
While we must resolve the key issue of reliance on
fossil fuels, we should acknowledge their contribution to
huge improvements in global health and development
over the past 100 years. In the industrialised world and
richer parts of the developing world, fossil fuel energy
has contributed to a doubled longevity, dramatically
Lancet 2009; 373: 1693–733
See Perspectives page 1669
Institute for Global Health
(Prof A Costello FRCPCH,
S Ball BSc, C Patterson LLB);
UCL Medical School
(M Abbas, J Patel BSc);
Development Planning Unit
(A Allen PhD, C Levy MA,
J A Puppim de Oliveira PhD);
Department of Civil,
Environmental, and Geomatic
Engineering (S Bell PhD);
Department of Political Science
(Prof R Bellamy PhD);
Department of Epidemiology
and Public Health (S Friel PhD);
Leonard Cheshire Disability and
Inclusive Development Centre
(Prof N Groce PhD, M Kett PhD);
Division of Population Health
(Prof A Johnson MD); Faculty of
Laws (Prof M Lee LLM,
Prof J Scott LLM); UCL
Environment Institute
(Prof M Maslin PhD); Centre for
International Health and
Development (D McCoy DrPH);
Aon Benfield UCL Hazard
Research Centre
(Prof B McGuire PhD,
J Twigg PhD); Institute for
Human Health and
Performance
(Prof H Montgomery MD);
Lancet and University College London Institute for
Global Health Commission
Managing the health effects of
climate change
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1694 www.thelancet.com Vol 373 May 16, 2009
reduced poverty, and increased education and security
for most populations.
Climate change effects on health will exacerbate
inequities between rich and poor
Climate change will have its greatest effect on those who
have the least access to the world’s resources and who
have contributed least to its cause. Without mitigation
and adaptation, it will increase health inequity especially
through negative effects on the social determinants of
health in the poorest communities.
Despite improvements in health with development, we
are still faced with a global health crisis. 10 million
children die each year; over 200 million children under
5 years of age are not fulfilling their developmental
potential; 800 million people go to bed each night hungry;
and 1500 million people do not have access to clean
drinking water. Most developing countries will not reach
the Millennium Development Goal health targets by
2015. In September, 2008, the WHO Commission on
Social Determinants of Health reported that social
inequalities are killing people on a grand scale, and noted
that a girl born today can expect to live up to 80 years if
she is born in some countries but less than 45 years if
she is born in others. The commission concluded that
health equity is achievable in a generation, it is the right
thing to do, and now is the right time to do it.
The effects of climate change on health are inextricably
linked to global development policy and concerns for
health equity. Climate change should catalyse the drive to
achieve the Millennium Development Goals and to
expedite development in the poorest countries. Climate
change also raises the issue of intergenerational justice.
The inequity of climate change—with the rich causing
most of the problem and the poor initially suffering most
of the consequences—will prove to be a source of
historical shame to our generation if nothing is done to
address it. Raising health status and reducing health
inequity will only be reached by lifting billions out of
poverty. Population growth associated with social and
economic transition will initially increase carbon
emissions in the poorest countries, in turn exacerbating
climate change unless rich countries, the major
contributors to global carbon production, massively
reduce their output.
Luxury emissions are different from survival emissions,
which emphasises the need for a strategy of contraction
and convergence, whereby rich countries rapidly reduce
emissions and poor countries can increase emissions to
achieve health and development gain, both having the
same sustainable emissions per person.
Key challenges in managing health effects of climate
change
The UCL Lancet Commission has considered what the
main obstacles to effective adaptation might be. We have
focused on six aspects that connect climate change to
adverse health outcomes: changing patterns of disease
and mortality, food, water and sanitation, shelter and
human settlements, extreme events, and population and
migration. Each has been considered in relation to five
key challenges to form a policy response framework:
informational, poverty and equity-related, technological,
sociopolitical, and institutional.
Our capacity to respond to the negative health effects of
climate change relies on the generation of reliable,
relevant, and up-to-date information. Strengthening
informational, technological, and scientific capacity
within developing countries is crucial for the success of a
new public health movement. This capacity building will
help to keep vulnerability to a minimum and build
resilience in local, regional, and national infrastructures.
Local and community voices are crucial in informing this
process.
Weak capacity for research to inform adaptation in poor
countries is likely to deepen the social inequality in
relation to health. Few comprehensive assessments on
the effect of climate change on health have been
completed in low-income and middle-income countries,
and none in Africa. This report endorses the 2008 World
Health Assembly recommendations for full documentation
of the risks to health and differences in vulnerability
within and between populations; development of health
protection strategies; identification of health co-benefits
of actions to reduce greenhouse gas emissions;
development of ways to support decisions and systems to
predict the effect of climate change; and estimation of
the financial costs of action and inaction.
Policy responses to the public health implications of
climate change will have to be formulated in conditions of
uncertainty, which will exist about the scale and timing of
the effects, as well as their nature, location, and intensity.
A key challenge is to improve surveillance and primary
health information systems in the poorest countries, and
to share the knowledge and adaptation strategies of local
communities on a wide scale. Essential data need to
include region-specific projections of changes in
health-related exposures, projections of health outcomes
under different future emissions and adaptation
scenarios, crop yields, food prices, measures of household
food security, local hydrological and climate data,
estimates of the vulnerability of human settlements (eg,
in urban slums or communities close to coastal areas),
risk factors, and response options for extreme climatic
events, vulnerability to migration as a result of sea-level
changes or storms, and key health, nutrition, and
demographic indicators by country and locality.
We also urgently need to generate evidence and
projections on health effects and adaptation for a more
severe (3–4°C) rise in temperature, which will almost
certainly have profound health and economic
implications. Such data could increase advocacy for
urgent and drastic action to reduce greenhouse gas
emissions.
Department of Anthropology
(Prof D Napier DPhil,
Prof N Redclift DPhil); Clinical
Operational Research Unit
(C Pagel PhD); Department of
Life Sciences (H Rees);
Department of Economics
(D Rogger MPhil); Institute for
Women’s Health
(Prof J Stephenson FFPH); and
Department of Philosophy
(Prof J Wolff MPhil), UCL
(University College London),
London, UK
*Mr Patterson died in
September, 2008
Correspondence to:
Prof Anthony Costello, UCL,
30 Guilford Street, London
WC1N 1EH, UK
a.costello@ich.ucl.ac.uk
Tannis Davidson (UCL Bartlett School) Science Photo Library
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The reduction of poverty and inequities in health is
essential to the management of health effects of climate
change. Vulnerability of poor populations will be caused by
greater exposure and sensitivity to climate changes and
reduced adaptive capacity. Investment to achieve the
Millennium Development Goals will not only reduce
vulnerability but also release public expenditure for climate
change currently consumed by basic prevention strategies
(eg, malaria control). Health-oriented and climate-orientated
investments in food security, safe water supply, improved
buildings, reforestation, disaster risk assessments,
community mobilisation, and essential maternal and child
health and family planning services, will all produce
dividends in adaptation to climate change.
Poverty alleviation and climate adaptation measures
will be crucial in reducing population growth in countries
where demographic transition (to stable and low fertility
and death rates) is delayed. Population growth will
increase overall emissions in the long term and expand
the number of vulnerable individuals (and thus the
potential burden of suffering) greatly.
The application of existing technologies is as important
as the development of new ones. Nonetheless,
technological development is needed to boost food
output, to maintain the integrity of ecosystems, and to
improve agricultural and food system practices (agriculture
is responsible for an estimated 22% of greenhouse
gas emissions), to improve systems for safely storing and
treating water, to use alternative supplies of water, for
waste water recycling and desalination, and for water
conserving technologies. It is also needed to create
buildings that are energy efficient and use low-carbon
construction materials; to allow for planning settlements,
and to develop software of planning and land use; to
increase regional and local climate modelling, creating
effective early warning systems, and the application of
geographic information systems; and to ensure the
provision of existing health and family planning services
at high coverage, and thus ensure the rights of individuals
and couples to have good health outcomes and access to
voluntary family planning methods.
Incentives for the development of technologies are
necessary to address the negative public health consequences
of climate change in poor countries. In the
pharmaceutical sector, rich markets generate vigorous
research and drug development activities, whereas poor
markets have been mainly ignored. Public funding for
investment in developing green technologies for poor
markets will be essential.
The biggest sociopolitical challenge affecting the
success of climate change mitigation is the lifestyle of
those living in rich nations and a small minority living in
Mark Maslin
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1696 www.thelancet.com Vol 373 May 16, 2009
poor nations, which is neither sustainable nor equitable.
Behavioural change will depend upon information,
incentives, and emphasis on the positive benefits of
low-carbon living. Sustainable consumption requires
accessible information for all about carbon footprints
arising from the lifecycle of economic products and our
energy usage. A step towards low-carbon living has health
benefits that will improve quality of life by challenging
diseases arising from affluent high-carbon societies—
obesity, diabetes, and heart disease especially—and
reducing the effects of air pollution.
Building social capital through community mobilisation
will improve adaptation strategies in both rich and poor
communities. Psychosocial health will be affected by
environmental change and uncertainty about the future;
therefore, public engagement about scientific findings
must be undertaken with responsibility and care.
Continuing population growth poses a further, important,
long-term issue for climate mitigation; better health and
development is the best way to ensure fertility declines,
but re-energising the provision of high-quality family
planning services where there is unmet need is also
important.
Climate change adaptation requires improved coordination
and accountability of global governance. Too
much fragmentation and too many institutional turf wars
exist. Vertical links need attention: we might need local
action to prevent local flooding and global action to
ensure that funding is available. Horizontal coordination
requires joined up thinking across governments and
international agencies. Governance at the global level,
especially in UN institutions, is characterised by a lack of
democratic accountability and profound inequalities.
These deficiencies will be exposed by climate change
negotiation with countries in the developing world.
Funding initiatives are insufficient and poorly
coordinated. In adapting effectively to climate change,
we need to consider market failures, the role of a powerful
transnational corporate sector, political constraints on
both developed and developing countries, whose
electorates might demand a greater focus on short-term
issues or wealth creation, and the need to strengthen
local government. Power and politics will enter all
discussions about food security, water supply, disaster
risk reduction and management, urban planning, and
health and population expenditure.
A new public health movement will increase advocacy
to reduce climate change
We call for a public health movement that frames the
threat of climate change for humankind as a health issue.
Apart from a dedicated few, health professionals have
come late to the climate change debate, but health concerns
are crucial because they attract political attention.
This report raises many challenging and urgent issues
for politicians, civil servants, academics, health professionals,
NGOs, pressure groups, and local communities.
The global financial crisis has stimulated governments
of industrialised countries to talk about the so-called
green new deal, which brings about re-industrialisation
based on low-carbon energy. Ideas such as carbon
capture in power stations, carbon taxes with 100%
dividends for low-carbon users, and fourth generational
nuclear power are on the highest political agendas. The
Copenhagen UN Framework Convention on Climate
Change (UNFCCC) conference in December, 2009
(COP 15) will address the shared vision of governments
about new global warming and emissions targets for
2020 and 2050. It will also address reform of the Clean
Development Mechanism, reducing emissions from
deforestation, technology transfer, and adaptation.
ENSO
triggering
Change in
ENSO
amplitude
or frequency
Permafrost and
tundra loss? Boreal
forest
dieback
Indian
monsoon
chaotic
multistability
Boreal
forest
dieback
Amazon
rainforest
dieback
Sahara greening
West African
monsoon shift
Instability of
West Antarctic
ice sheet
Changes in
Antarctic
water formation
Arctic
sea-ice loss
Greenland
ice sheet
melting
Atlantic
deep water
formation
Figure 1: Potential tipping points in climate systems3
ENSO=El Niño southern oscillation. Boreal forest is the most northern woodland
area. Tundra is a vast, mostly flat, treeless Arctic region of Europe, Asia, and
North America in which the subsoil is permanently frozen.
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The ability of health systems to respond effectively to
direct and indirect health effects of climate change is a
key challenge worldwide, especially in many low-income
and middle-income countries that suffer from disorganised,
inefficient, and under-resourced health
systems. For many countries, more investment and
resources for health systems strengthening will be
required. Climate change threats to health also highlight
the vital requirement for improved stewardship,
population-based planning, and the effective and
efficient management of scarce resources.
Recommendations on management of the health
effects of climate change are listed at the end of this
report.
Introduction
The potential health effects of climate change are
immense. Management of those health issues is an
enormous challenge not only for health professionals but
also for climate change policy makers. An integrated and
holistic political response is vital for good social,
economic, and ethical reasons. Consistent with this
ambition, we have brought together a multidisciplinary
group to explore this urgent issue.
Anthropogenic climate change is now incontrovertible.
The amount of change and its intensity, along with the
willingness and capacity to mitigate it, are subject to
considerable debate and controversy. This report
deliberately supports a conservative approach to the
agreed facts for two reasons. First, even the most
conservative estimates are profoundly disturbing and
demand action. Second, less conservative climate change
scenarios are so catastrophic that adaptation might be
unachievable. However, although conservative on the
estimates and cognisant of the possibility of pessimistic
outcomes, we are optimistic on what can be achieved by
a collaborative effort between governmental and
non-governmental entities at all levels, and concerned
citizens at the community level.
The Intergovernmental Panel on Climate Change
(IPCC) reported that societies can respond to climate
change by adapting to its effects and by reducing
greenhouse gas emissions (mitigation), thereby
decreasing the rate and magnitude of change.1 The
capacity to adapt and mitigate depends on socioeconomic
and environmental circumstances, and the availability of
information and technology. Less information is available
about the costs and effectiveness of adaptation measures
than about mitigation measures.
Climate change is not just an environmental issue but
also a health issue. The ability to adapt to the health
effects of climate change depends on measures that
reduce its severity—ie, mitigation measures that will
drastically reduce carbon emissions in the short term,
but also increasing the planet’s capacity to absorb carbon.
This is a crucial issue that must be acted upon urgently.
However, we only focus on how we might adapt to and
avoid the negative health effects of climate change that,
because it can take 20–30 years for carbon emissions to
have a full effect, and for deforestation and ecosystem
damage to become apparent, will occur even with the
best possible mitigation action. In this report, we review
the consensus science on climate change and then
briefly explore its health implications. We address six
ways in which climate change can affect health: changing
patterns of disease and morbidity, food, water and
sanitation, shelter and human settlements, extreme
events, and population and migration. We then present a
policy framework to address the major obstacles to
responses to the health effects of climate change, and
how policy responses might address these issues.
Climate science and the effect of climate change
on health
In 1896, the Swedish scientist Svante Arrhenius
suggested that human activity could substantially warm
the earth by adding CO2 to the atmosphere. His
predictions were subsequently independently confirmed
by Thomas Chamberlin.2 At that time, however, such
effect on human beings was thought to be dwarfed by
other influences on global climate, such as sunspots and
ocean circulation. However, these observations went
unappreciated until recently.
The establishment of the IPCC in 1988 was a pivotal
move by the world community to address this issue, and
has made a huge difference to the evolution of a shared
understanding of climate change and to the stimulus for
more and better research and modelling.
The greenhouse effect
The temperature of the earth is determined by the
balance between energy input from the sun and its loss
back into space. Indeed, of the earth’s incoming solar
short-wave radiation (ultraviolet radiation and the visible
spectrum), about a third is reflected back into space. The
remainder is absorbed by the land and oceans, which
radiate their acquired warmth as long-wave infrared
radiation. Atmospheric gases—such as water vapour,
CO2, ozone, methane, and nitrous oxide—are known as
greenhouse gases and can absorb some of this long-wave
radiation and are warmed by it. This greenhouse effect is
needed because, without it, the earth would be about
35°C colder.3 Plants take up water and CO2 and, through
photosynthesis, use solar energy to create molecules they
need for growth. Some of the plants are eaten by animals.
Whenever plants or animals die, they decompose and the
retained carbon is released back into the carbon cycle,
most returning into the atmosphere in gaseous form.
However, if organisms die and are not allowed to rot, the
embedded carbon is retained. Over a period of about
350 million years (but mainly in the Carboniferous
period), plants and small marine organisms died and
were buried and crushed beneath sediments, forming
fossil fuels such as oil, coal, and natural gas. The
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industrial revolution started a large-scale combustion of
these fossil fuels, releasing carbon back into the
atmosphere, increasing the concentrations of greenhouse
gases in the atmosphere and resulting in an increased
greenhouse effect. Consequently, the temperature of the
earth started to rise.
Anthropogenic climate change
Industrial human activity has released vast quantities of
greenhouse gases—ie, about 900 billion tonnes of CO2,
of which about 450 billion tonnes has stayed in the
atmosphere. About 80% of CO2 is caused by
industrialisation and the rest by land use such as
deforestation. The first direct measurements of
atmospheric CO2 concentrations were made in 1958 at
an altitude of about 4000 m on the summit of Mauna
Loa in Hawaii, a remote site free from local pollution.
Ice-core data indicate preindustrial CO2 concentrations
of 280 parts per million by volume (ppmv). In 1958,
atmospheric CO2 concentration was 316 ppmv, and has
risen every year reaching 387 ppmv in 2008. CO2
concentrations over the last 650 000 years have ranged
between 180 and 300 ppmv, with changes of 80 ppmv
between the regular waxing and waning of the great ice
ages. Pollution that we have caused in one century is
thus comparable to natural variations that have taken
thousands of years.3
The increase in greenhouse gases has already substantially
changed climate; average global temperatures
have risen 0·76°C and the sea level has risen over 4 cm.
Seasonality and intensities of precipitation, weather
patterns, and substantial retreat of the Arctic sea ice and
almost all continental glaciers have dramatically
changed.4 The 12 warmest years on record within the
past 150 years have been during the past 13 years: 1998
was the warmest, followed by 2005, 2002, 2003, and
2004. The IPCC states that the evidence for global
warming is unequivocal and is believed to be due to
human activity.4 This idea is supported by many
organisations, including the Royal Society and the
American Association for the Advancement of Science.
Predicted climate change
The IPCC has synthesised the results of 23 atmosphere–
ocean general circulation models to predict future
temperature rises on the basis of six emission scenarios.4
They report that global mean surface temperature could
rise between 1·1°C and 6·4°C by 2100, with best estimates
between 1·8°C and 4·0°C. Most variation, especially in
the latter two-thirds of this century, indicates the
unavoidable uncertainty over future choices, trajectories,
and behaviours of human societies. Furthermore, global
CO2 emissions are rising faster than the most dire of the
IPCC emission scenarios.5 The models also predict an
increase in global mean sea level of 18–59 cm. If the
contribution from the melting of ice of Greenland and
Antarctica is taken into account, this range increases to
28–79 cm by 2100.4 All these predictions are based on the
assumption of a continued linear response between
global temperatures and ice-sheet loss. This response is
unlikely because of positive feedback loops in the global
warming system, and sea level rise could thus be much
higher. Some leading climate scientists have raised the
concern that the IPCC 2007 predictions are too
conservative,6–8 although this is still viewed as controversial.
Scientists are also concerned by tipping points in
the climate system. The term tipping points commonly
refers to a critical threshold at which a tiny perturbation
can qualitatively alter the state or development of a
system. Lenton and colleagues9 used the term tipping
element to describe large-scale components of the earth
system that might pass a tipping point. They mainly
looked at tipping elements that could be triggered this
century. The greatest threats are the artic sea ice and the
Greenland ice sheet, with other five potential elements:
the west Antarctic ice sheet, the Atlantic thermohaline
circulation, El Niño southern oscillation, Indian summer
monsoon, Amazon rainforest, and boreal forest. Tipping
points might either accelerate global warming or have a
disproportionate effect on humanity (figure 1).
Uncertainty in predictions however is not an excuse for
inaction (panel 1).
Global warming
The effects of global warming will substantially increase
as the temperature of the planet rises.1,11 The return period
and severity of floods, droughts, heatwaves, and storms
will worsen. Coastal cities and towns will be especially
vulnerable as sea level rise will increase the effects of
floods and storm surges. Increased frequency and
magnitude of extreme climate events together with
reduced water and food security will have a severe effect
Panel 1: The precautionary principle
The meaning and role of the precautionary principle is
unsettled and disputed, but at its core is the pervasiveness
of scientific uncertainty. Whilst it never dictates a specific
course of action, and often tradeoffs need to be made
between costs and risks of acting and those of not acting,
the precautionary principle reminds us that uncertainty is
not a reason to postpone or avoid action. This principle is
enshrined in Bradford-Hill’s article,10 which states that “all
scientific work is incomplete—whether it be observational
or experimental. All scientific work is liable to be upset or
modified by advancing knowledge. This does not confer
upon us a freedom to ignore the knowledge that we already
have, or to postpone the action that it appears to demand
at a given time”. It might be objected that this principle
adds little to what we expect from good decision making.
However, decision making can disregard uncertain
effects, taking a short-term approach and focusing instead
on the certain costs of taking action.
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on public health of billions of people.11 Global warming
also threatens global biodiversity. Ecosystems are already
being hugely degraded by habitat loss, pollution, and
hunting. The millennium ecosystem assessment12
suggested that three known species are becoming extinct
every hour, whereas the 2008 living planet report13
suggested that biodiversity of vertebrates had fallen by
over a third in just 35 years, an extinction rate 10 000 times
faster than any observed in the fossil record. Global
warming is likely to exacerbate such degradation.
Economic consequences will be severe,14 and mass
migration and armed conflict might result.
A more pessimistic scenario could occur if the observed
temperature rise approaches the higher end of the IPCC
expected scenarios. Sustained global temperature rises of
5–6°C could lead to the loss of both Greenland and the
western Antarctic ice sheets by the middle of the next
century, raising sea levels by up to 13 m.3,7,8 The UK
Environment Agency has plans to deal with a rise of
4·5 m through construction of a barrier across the mouth
of the river Thames, stretching 15 miles from Essex to
Kent. However, a 13-m rise would cause the flooding and
permanent abandonment of almost all low-lying coastal
and river urban areas. Currently, a third of the world’s
population lives within 60 miles of a shoreline and 13 of
the world’s 20 largest cities are located on a coast. More
than a billion people could be displaced in environmental
mass migration. A stable coastline would not be reestablished
for hundreds of thousands of years. The
north Atlantic ocean circulation (which includes the Gulf
Stream circulation) could collapse plunging western
Europe into a succession of severe winters followed by
severe heatwaves during summer. An additional 2 billion
people would be water stressed, while billions more
would face hunger or starvation. The risk of armed
conflict would rise. Public health systems around the
world would be damaged, some to the point of collapse.
Global biodiversity would be devastated.
Future climate targets
What level of climate change is safe? In February, 2005,
the British Government convened an international
science meeting in Exeter, UK, to discuss this topic. Their
recommendation is that global warming must be limited
to a maximum of 2°C above preindustrial average
temperature.15 Below this threshold, there are both
winners and losers due to regional climate change, but
above this figure everyone might lose. However,
temperature rises are likely to exceed this threshold: a
rise of 0·76°C has already occurred and, even if we had
Key elements Contrast Graph ma rks Arrows Font reference and special characters
Climate change map_2
Urgent
Africa region
Eastern Mediteranean region
South America and Caribbean region
Southeast Asia region
Western Pacific region*
Developed countries†
1894
768
92
2572
169
8
World 5517
*Without developed countries. †And Cuba.
Total DALYs
(1000s)
DALYs
per million population
Region
920·3
3071·5
1586·5
188·5
1703·5
111·4
8·9
Figure 2: Estimated effects of climate change in 2000, by WHO region16
DALY=disability adjusted life year.
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stopped all emissions in 2000, there would still be another
0·6°C rise by 2050.4
The cost of climate mitigation and adaptation
What is the cost of avoiding climate change? According
to the UK Government commissioned Stern review on
the economics of climate change in 2006, if we do
everything we can now to reduce global greenhouse gas
emissions and ensure we adapt to the future effects of
climate change, the average estimated cost is 1% of the
world gross domestic product (GDP) every year.14
However, if we do nothing, the effects of climate change
could cost 5–20% of the world GDP every year. These
figures have been disputed. Pielke and colleagues5 argue
that the cost of converting the global economy to low
carbon could be more than 1% of the world GDP because
global emissions have risen faster than the worst
predictions. Stern has recently revised the estimate to
2% of the world GDP. However, Parry and colleagues12
suggest that the effects and the associated costs of global
warming have been underestimated by the IPCC1 and
Stern.14 The potential costs or benefits to global health of
mitigating and adapting have not yet been established.
Even if the benefit–cost ratio of solving global warming is
less than that suggested by Stern, the ethical issue of
preventing deaths of tens of millions of people and the
increase in human misery for billions is clear.
Climate change and health
Climate change and its rapid emergence in the past
decades are a major challenge to public health together
with poverty, inequity, and infectious and noncommunicable
diseases. Furthermore, the poorest
countries will suffer the greatest consequences of climate
change even though they contributed the least for
emissions.
Climate change has been responsible for 5·5 million
disability adjusted life years (DALYs) lost in 2000
(figure 2). Although influential in stimulating action on
climate change, these initial assessments of the disease
Figure 3: Effects of global average temperature change1
*Significant is defined as more than 40%. †Based on average rate of sea level rise of 4·2 mm per year from 2000 to 2080. The black lines link effects caused by climate
change, whereas the broken arrows indicate effects continuing with increasing temperatures. Entries are placed so that the left-hand side of the text indicates the
approximate level of warming associated with the onset of a given effect.
Global average annual temperature change relative to 1980–99 (°C)
Increased water availability in moist tropics and high altitudes
Decreasing water availability and increasing drought in middle latitudes and semi-arid low latitudes
Hundreds of millions of people exposed to increased water stress
Up to 30% of species at
increasing risk of extinction
Increased coral bleaching
Increasing species range shifts and wildfire risk
Complex, localised negative effects on smallholders, subsistence farmers, and fishermen
Tendencies for some cereal productivity
to increase at middle-to-high latitudes
Increased damage from floods and storms
About 30% of global
coastal wetlands lost†
Millions more people could experience
coastal flooding each year
Increasing burden from malnutrition, diarrhoea, and cardiorespiratory and infectious diseases
Increased morbidity and mortality from heatwaves, floods, and droughts
Changed distribution of some disease vectors
Substantial burden on health services
0 1 2 3 4 5
Coasts
Health
Food
Ecosystems
Water
Tendencies for cereal productivity
to decrease in low latitudes
Productivity of all cereals
decreases in low latitudes
Cereal productivity to
decrease in some regions
Ecosystem changes due to weakening of the meridional
overturning circulation
Most corals bleached Widespread coral mortality
Terrestrial biosphere tends towards a net carbon source as:
~15% ~40% of ecosystems affected
Significant* extinctions
around the globe
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burden attributable to climate change were conservative
and relate only to deaths caused by cardiovascular
diseases, diarrhoea, malaria, accidental injuries in coastal
floods and inland floods or landslides, and the
unavailability of recommended daily calorie intake
(which is an indicator of malnutrition). However,
estimates show that small increases in the risk for
climate-sensitive conditions, such as diarrhoea and
malnutrition, could result in very large increases in the
total disease burden. DALY combines the time lived with
disability and the time lost due to premature mortality.
The IPCC’s fourth assessment report reviewed over
500 published articles on the effects of heat and cold;
wind, storms, and floods; drought, nutrition, and food
security; food safety; water and disease; air quality and
aeroallergens and disease; vector-borne, rodent-borne,
and other infectious diseases; occupational health and
ultraviolet radiation (figure 3).
In addition to these direct health effects, climate change
will have indirect substantial consequences on health.
Economic collapse will devastate global health and
development. Mass environmental displacement and
migration will disrupt the lives of hundreds of millions
of people, exacerbating the growing issues associated
with urbanisation and reverse successes in development.
Conflict might result from resource scarcity and
competition, or from migration and clashes between host
and migrant groups.
From a conservative perspective, although a minority
of populations might experience health benefits (mostly
related to a reduction in disease related to cold weather),
the global burden of disease and premature death is
expected to increase progressively.16 These projections
were made using emissions data obtained before 2000.
Work done after the IPCC 2007 report by Canadell and
colleagues17 compared data from the 1990s with those of
2000–06, and found that CO2 emissions growth rate
increased from 1·3% to 3·3% every year, suggesting that
the current carbon cycle is generating more severe
climate change sooner than expected. This finding has
serious implications for health. Not only the scale of
consequences of climate change on health is much larger
but the period in which to implement effective adaptive
strategies is shorter, threatening to widen social and
health inequities even further. The countries most
severely affected by climate change are often those most
under-resourced in terms of financial, infrastructure, and
human capacity to respond. New estimates of disease
burden and comparative risk assessments are currently
being developed and should provide data for relative
current and future health outcomes.
Global health inequities and climate change
“The rich will find their world to be more expensive,
inconvenient, uncomfortable, disrupted and colourless;
in general, more unpleasant and unpredictable, perhaps
greatly so. The poor will die.”18
Modern society has done much good for the health and
wellbeing of many people. However, large health
inequities within and between countries exist. In Japan
or Sweden, for example, children can expect to live more
than 80 years; in Brazil, 72 years; in India, 63 years; and
in several African countries, less than 50 years.19 The
WHO Commission on the Social Determinants of
Health reported that social inequities are killing people
on a grand scale. The report suggested that “the toxic
combination of bad policies, economics, and politics is,
in large measure, responsible for the fact that a majority
of people in the world do not enjoy the good health that
is biologically possible”.19 The damage done to the
environment by modern society is perhaps one of the
most inequitable health risks of our time. The carbon
footprint of the poorest 1 billion people is around 3% of
the world’s total footprint;20 yet, these communities are
affected the most by climate change (figure 4). Adverse
health outcomes are likely to be greatest in low-income
countries and in poor people living in urban areas,
elderly people, children, traditional societies, subsistence
farmers, and coastal populations.1,22 Loss of healthy life
years as a result of global environmental change
(including climate change) is predicted to be 500 times
greater in poor African populations than in European
populations.23 The observed variation is due to several
factors: regional variation in predicted rates and types of
climatic change; differing underlying vulnerabilities
(such as existing levels of heat and food stress, and
exposure to disease vectors); and differing capacities to
adapt to changing conditions (related to governance and
resources nationally and individual incomes).24 These
differences in the effects of climate change are due to
existing economic, social, and heath inequities.25
Recent scientific findings
This report is mainly based on the consensus findings
from the 2007 IPCC report. Recent scientific findings,
however, increased the concerns arising from the IPCC
report. In March, 2009, in Copenhagen (Denmark), an
international scientific congress on climate change was
attended by more than 2500 delegates from about
80 countries.26 This congress raised several concerns:
• Recent observations confirm that, because of high rates
of observed emissions, the worst-case IPCC scenario
trajectories (or even worse) are being realised for
parameters such as global mean surface temperature,
sea level rise, ocean and ice-sheet dynamics, ocean
acidification, and extreme climatic events. Many
parameters might worsen, leading to an increasing risk
of abrupt or irreversible climatic shifts.
• Societies are highly vulnerable to even modest climate
change, with poor nations and communities especially
at risk. Temperature rises above 2°C will be challenging
for contemporary societies to cope with and will
increase the level of climate disruption through the
rest of the century.
IPCC Hang Kei Ho (UCL Geography)
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• Rapid, sustained, and effective mitigation based on
coordinated global and regional action is required to
avoid dangerous climate change, regardless of how it
is defined. Delay in initiating effective mitigation
actions increases greatly the long-term social and
economic costs of both adaptation and mitigation.
• Climate change is having, and will have, very different
effects on people within and between countries and
regions, on present and future generations, and on
human societies and nature. An effective, well-funded
adaptation safety net is required for those people least
capable of coping with climate change, and a common
but differentiated mitigation strategy is needed to
protect the poor and most vulnerable people.
Management of the health effects of climate
change
Climate change will lead to adverse health effects in
many ways. If we are about to take effective action to keep
health effects of climate change to a minimum, we need
to understand the consequences of climate change on
health and the possibilities for change or adaptation. In
the case, for example, of health threats through changing
patterns of disease due to insect-borne infections, various
responses are possible—such as vector control,
promotion of mosquito nets, new vaccines, or rapid and
effective diagnosis and treatment. By contrast, in the case
of malnutrition due to food shortages, public health and
medical approaches can provide, at best, only temporary
relief, and a sustainable solution can only be found in
measures that match food supply to need and ensure
economic entitlements in the most vulnerable groups.27
The ability to mount responses in any circumstance
might be limited by the degradation of infrastructure and
by the economic stressors that climate change brings.
Accordingly, we consider six ways that link climate
change to health. These are changing patterns of disease
and mortality, extreme events, food, water, shelter, and
population. There are, of course, many overlaps and
common elements. However, each should be independently
considered to understand the possibilities of
action to adapt to climate change, and the dangers if such
possibilities are not adopted.
Patterns of disease and mortality
Climate change will affect health directly through a
complex set of interdependent interactions. Regional
weather changes in temperature, sea level, precipitation,
and extreme weather events will cause downstream
effects on the environment that lead to adverse health
effects. The epidemiological outcome of climate change
on disease patterns worldwide will be profound,
especially in developing countries where existing
vulnerabilities to poor health remain. The added
pressure of climate change to the environment will
worsen this burden and pose challenging questions for
public and global health.
Global temperature rise will directly affect health. The
heatwaves of 2003 in Europe caused up to 70 000 deaths,
especially from respiratory and cardiovascular causes.28
Rising temperatures are likely to generate heat-related
stress, increasing the short-term mortality rate due to
heatstroke.29 Regions that are heavily urbanised will be
more adversely affected than rural ones. Urban
populations are especially vulnerable to climate change,30
as are people with a pre-existing respiratory disease.31
Modelling of climate change in the Gulf predicts increased
mortality rates due to cardiovascular and respiratory
illnesses, thermal stress, and increased frequency of
infectious vector-borne diseases in 2070–99.32 The
California heatwave of 2006 showed large increases in
admissions to hospitals from cardiovascular and other
illnesses, and the heatwave in Germany in 2003 increased
mortality rates, especially from respiratory causes.33,34
Furthermore, the urban population in developing
countries is projected to increase from 2·3 billion in 2005
to 4 billion by 2030, which is compounded by expanding
urban sprawl and poor housing.35 This change will
inevitably increase the risk of heatwaves and heatstrokes
in cities in developing countries as a result of the so-called
heat island effect.
Rising temperatures will also affect the spread and
transmission rates of vector-borne and rodent-borne
diseases. Temperature affects rate of pathogen
maturation and replication within mosquitoes, the
density of insects in a particular area, and increases the
likelihood of infection. Therefore, some populations
who have little or no immunity to new infections might
be at increased risk. Vector reproduction, parasite
development cycle, and bite frequency generally rise
with temperature; therefore, malaria, tick-borne
encephalitis, and dengue fever will become increasingly
widespread. In some cases, extreme events, such as
heavy rains, will wash away eggs and larvae and decrease
vector populations.
Mosquitoes responsible for malaria will grow, by
accessing warm high altitudes, in places once free of the
disease.36 Lindsay and Martens37 have used models and
scenarios to estimate that 260–320 million more people
will be affected by malaria by 2080 as a consequence of
new transmission zones. Other studies provide similar
estimates.38,39 Pascual and colleagues40 modelled the
population dynamics of mosquitoes in relation to
warming in east African highlands. They found that
mosquito abundance is amplified with warming, with
an over ten-fold increase with every unit increase (0·1°C)
in temperature.
In Kenya, meteorological factors were associated with
malaria incidence, with temperature having the largest
effect.41 This finding suggests that temperature rises will
increase malaria cases. Reiter and colleagues42 have
cautioned against attributing malaria dynamics to climate
change and point to the uncertainties of predicting
malaria epidemics nationally and locally.
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Dengue fever is sensitive to climate. The disease is
prominent in urban areas because of inadequate water
storage that affects about 100 million people worldwide.
Climate change will increase the number of regions
affected by arbovirus, such as Australia and New Zealand.
Heavy rainfall and a rise in temperature increase the rate
of infection.43 By 2080, about 6 billion people will be at
risk of contracting dengue fever as a consequence of
climate change, compared with 3·5 billion people if the
climate remained unchanged.1,44
Schistosomiasis, fascioliasis, alveolar echinococcosis,
leishmaniasis, Lyme borreliosis, tick-borne encephalitis,
and hantavirus infections are all projected to increase as
a result of global climate change.45–49
However, some research attributed changes in disease
patterns, such as for tick-borne encephalitis, to socioeconomic
rather than climate change.50,51 There is no
clear evidence at present for a climate effect on influenza
or avian flu.52
The spread of animal infections, such as blue-tongue
virus and other Orbiviruses, provides further evidence of
the consequence of climate change on vector-borne
diseases.53
The extinction of species across the globe arising from
habitat fragmentation, climate change, pollution, and the
rapid global movement of people and other living organisms
have worked synergistically to diminish ecosystem
function. Ecosystem modifications through climate
change and other anthropogenic changes to the environment
could lead to catastrophic disease outbreaks.54
Climate change will strain health resources of those
countries that already face the public health challenges
A
B
0–1
1–5
5–10
10–35
35–57
0–2
2–4
4–70
70–120
Billion tons carbon
Mortality per
million population
Figure 4: Density-equalising cartogram
Comparison of undepleted cumulative CO2 emissions by country for 1950–2000 versus the regional distribution of four climate-sensitive health consequences (malaria, malnutrition, diarrhoea, and
inland flood-related fatalities).21
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of poor health infrastructure, poverty, and inequality.
Diminished biodiversity might reduce the risk of a disease
being transmitted to human beings, a phenomenon
termed the dilution effect.55 Species might be competent
or incompetent in transmitting a disease to vectors that
feed upon them. Loss of biodiversity through climate
change could alter the proportions of competent and
incompetent hosts. Competent reservoir hosts tend to
thrive in species-poor communities, therefore vectors
are more likely to feed upon these competent reservoirs
and become infected, and the risk of human disease is
increased. This effect might occur in Lyme, West Nile,
and hantavirus diseases.
As ocean temperatures rise with global warming and
more intense El Niños, cholera outbreaks might
increase as a result of more plankton blooms providing
nutrients for Vibrio cholerae.22 In 1998, increased rainfall
and flooding after hurricane Mitch in Nicaragua,
Honduras, and Guatemala caused a leptospirosis
outbreak, and an increased number of cases of malaria,
dengue fever, and cholera. Floods also promote
outbreaks of cryptosporidiosis: in Wisconsin (USA) in
1993 there were 400 000 cases and 100 deaths.56
The ability of health systems to respond effectively to
the direct and indirect health effects of climate change is
a challenge worldwide, especially in many low-income
and middle-income countries, which suffer from
disorganised, inefficient, and under-resourced health
systems.
Food
Climate change threatens human health through its
effect on undernutrition and food insecurity.57 Chronic
and acute child malnutrition, low birthweights, and
suboptimal breastfeeding are estimated to cause the
deaths of 3·5 million mothers and young children every
year.58 Furthermore, one in three children under the age
of 5 years born in developing countries suffer from
stunting due to chronic undernutrition.
Climate change will compound existing food
insecurity.59 Before the current food crisis, more than
800 million people had calorie-deficient diets, mostly in
sub-Saharan Africa and south Asia. After the rise in food
prices in 2008, millions more—estimates range from
100 million to 850 million—might suffer hunger or food
insecurity.60 According to the UN World Food Programme,
the number of food emergencies every year has increased
from an average of 15 during the 1980s to more than 30.
Lobell and Asner61 showed that corn and soyabean
yields in the USA fell by 17% for every degree rise in
growing season temperature. Previous studies had
predicted changes of similar magnitude for a 3°C
temperature increase.62
Lobell and colleagues63 used statistical crop models and
climate projections for 2030 from 20 general circulation
models and showed that south Asia and southern Africa,
without sufficient adaptation measures, are likely to
suffer negative outcomes on crops that are important to
large food-insecure human populations, such as maize,
wheat, and rice.
Another study64 suggests that half of the world’s
population could face severe food shortages by the end of
the century because rising temperatures take their toll on
farmers’ crops. Harvests of staple food crops, such as rice
and maize, could fall between 20% and 40% as a result of
increased temperatures during the growing season in
tropical and subtropical regions. Battisti and Naylor64
combined IPCC climate models with historical examples
of the effects of heatwaves on agriculture, and found a
90% chance that, by the end of the century, the coolest
temperatures in tropical regions during the crop-growing
season would exceed the hottest temperatures recorded
between 1900 and 2006. Temperate regions, such as
Europe, will see previous record temperatures become
the norm by 2100.
Although agricultural productivity might increase in
some regions as a result of global warming (almost
entirely in the rich high-latitude countries, although
Sahara greening might benefit west Africa), hunger,
illness, and death due to undernutrition are set to worsen
as climate change affects crops, forestry, livestock,
fisheries, aquaculture, and water systems. Increases in
extreme weather events will damage crops and disrupt
farming.65 Sea level rise and flooding of coastal lands will
lead to salination or contamination of fresh water and
agricultural lands, and the loss of nursery areas for
fishing. Drought, and changing patterns of plant and
livestock diseases and pest infestations, reduction of
income from animal production, decreased crop yields,
lessened forest productivity, and changes in aquatic
populations will all affect food production and security.
The regions most likely to be adversely affected are those
already most vulnerable to food insecurity and
malnutrition, where production is undertaken by
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smallholder and subsistence farmers, pastoralists, traditional
societies, indigenous people, coastal populations,
and artisanal fisherfolk.59 Ironically, many food-insecure
people nowadays are small farmers, fishers, and herders.
Even though they grow food, many lack access to good
land, adequate agricultural inputs, and access to viable
markets, and thus lack the ability to meet their needs
through either production or purchase.66
The rise in food prices has also caused an upsurge in
the number of urban-based, food-insecure populations, a
trend that will grow as a result of people being forced to
migrate to urban areas as environmental migrants, and
because almost all global population growth over the next
30 years will occur in cities of developing countries.
In 2008, Josette Sheeran, director of the World Food
Programme, wrote that “in the fight against hunger we
could now be facing a perfect storm of challenges,
including climate change and increasingly severe
droughts and floods, soaring food prices and the tightest
supplies in recent history, declining levels of food aid,
and HIV/AIDS, which also aggravates food insecurity”.67
Water and sanitation
Safe and reliable access to clean water and good sanitary
conditions are essential for good health. Provision of
public health infrastructure has been key to economic,
social, and industrial development, and remains a
challenge in many parts of the world. In 2002, 21% of
people living in developing countries did not have
sustained access to an improved water source, and 51%
did not have access to improved sanitation.68 In 1995,
almost 1·4 billion people were living in water-stressed
regions, defined as rainfall runoff of less than 1000 m³
per person per year.69 The main health effects of lack of
access to clean water and sanitation are diarrhoeal and
other diseases caused by biological or chemical
contaminants. Poor drainage in human settlements
increases exposure to contaminated water and provides
habitat for mosquitoes, leading to increased incidence of
water-borne and vector-borne diseases.
In Delhi (India), for example, 15 million people face
serious water shortages, with water being transported up
to 300 km. The projected population of this municipality
is more than 30 million by 2025.70 Buildings in Mexico
City (Mexico) are sinking as a result of overexploitation of
the aquifers under the city, and the water distribution
network is losing 40% of water. Consequently, the city
now imports a third of its raw water, with the additional
costs of pumping it up 1000 m.71
Changing rainfall and temperature over the next
decades are likely to make provision of clean water, good
sanitation, and drainage even more complicated than it
is now. Average annual rainfall is forecast to decrease in
some regions and increase in others, and droughts and
floods are likely to become more frequent and intense.
Regional temporal patterns of rainfall might also be
altered: the problem is not simply sustained drought, but
also severe rainfall all at once followed by less rainfall,
thus annual rainfall might rise, but still cause drought.
Increased rainfall could reduce absolute water scarcity
in some regions. However, the health benefits of
increased rainfall in regions such as southeast Asia
depend on the capacity to store additional runoff, which
is predicted to occur during the wettest rather than
driest seasons.69 In other regions, such as the
Mediterranean, southern and central Africa, Europe,
and the southern USA, reduced annual rainfall and
growing populations are likely to increase the number
of people living under water stress.69 Water scarcity
might result in greater conflict between and within
countries and communities.
More than a sixth of the world’s population currently
live in glacial-fed water catchments, which are vulnerable
to climate change.14 Increasing rates of glacial melting
are predicted to lead to great reductions of water
availability. In the near future, high peak flows in
glacial-fed rivers are expected, as the rate of glacier-mass
loss increases, followed by dramatic reductions in river
flow and freshwater availability as glaciers progressively
disappear. Rising temperatures are also likely to result in
earlier snow thawing and increased rain relative to snow
precipitation, bringing peak river flows earlier in the
year, potentially exacerbating dry season water scarcity.72
In August, 2008, when the Kosi river changed course,
the Bihar flood (India) was probably partly caused by
increased river flow from glacial melting. The flood
affected 4·4 million people, destroyed 290 000 hectares
of land, and costed an estimated US$6·5 billion.
Reduced river flows and increased water temperature
will lead to declining water quality as the dilution of
contaminants is reduced, less oxygen is dissolved in
water, and microbiological activity increases.1,72 These
effects could lead to major health problems for vulnerable
people, especially during drought, and might increase
the risk of conflict and major population migration.
Shelter and human settlements
The management of health effects of climate change
related to shelter and human settlements requires not
only secure emergency shelter for those displaced or
affected by climate variability events, but also human
settlements prepared for the future climate-changed
environment. The process of urbanisation in the developing
world is structurally linked to increased environmental
vulnerability, with a high percentage of the
urban population exposed to climate-related hazards,
such as floods and landslides, as well as to related health
problems, such as disease and injury. Climate change
increases this vulnerability, especially for the poorest
and most powerless groups in society, as they often
have not been given opportunities to adapt. Thus,
poverty reduction needs to be placed at the forefront of
the debate on adapting human settlements to climate
change.
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Adaptation can prevent only some damage. Synergies
between development and climate change adaptation
exist: successful, well-governed cities that focus on
improved housing, living conditions, and infrastructure
will reduce poverty and, at the same time, adapt to climate
change.73
Urban settlements, especially cities, need to be adapted
in two ways. First, changing and designing settlements
that contribute less to the causes of climate change (eg,
building energy efficient and green housing). Second,
adapting settlements to be climate resilient and able to
cope with the increasing risks of climate change.
The need to improve the lives of 2·4 billion people
who rely on biomass for cooking and heating and
1·6 billion people who have no access to electricity
presents a major developmental challenge in many
developing countries.74 Those without access to electricity
for cooking, lighting, transport, communications, and
refrigeration are exposed to adverse health risks. Poor
people who have access to energy currently do so in the
worst way—ie, they have access to energy that is
expensive, polluting, limited, and disadvantageous to
women and children, both in terms of health risks and
the time spent in the collection of energy fuels. Reliance
on unclean burning of coal and biomass fuels is a cause
of much ill-health in developing countries.75 Therefore,
a need exists to improve access to secure, clean, reliable,
affordable, and sustainable sources of energy that can
provide essential services for a healthy, productive, and
safe life, strengthening the positive relation between
poverty reduction, health, energy security, and ecological
sustainability. Energy security is also an issue of growing
concern to many governments in both developed and
developing countries, and a potential source of
international tension and conflict.75
Extreme events
Major disasters caused by extreme natural events and
health are directly linked, especially in relation to
weather-related disasters, which can be expected to
increase in number and severity in a warmer planet.
Associated health problems72 can arise from the loss or
contamination of potable water leading to disease,
destruction of crops resulting in food shortages, poor
nutrition, and malnutrition. Health problems are
compounded by general infrastructure breakdown,
notably with respect to water supply, sanitation, and
drainage. In the long term, mental health conditions
after a disaster, such as depression and anxiety, can also
present serious problems.
In recent years, more than 2 billion people were affected
by natural disasters,76 many of which were directly or
indirectly related to extreme meteorological phenomena,
including heatwaves and coldwaves, floods, droughts,
and windstorms. A few examples of cities at risk from
floods or sea level rise include Alexandria (Egypt),
Cotonou (Benin), Dhaka (Bangladesh), Lagos and Port
Harcourt (Nigeria), Abidjan (Côte d’Ivoire), Mombasa
(Kenya), Buenos Aires (Argentina), and Bamenda
(Cameroon).73
Between 2004 and 2008, 40% of the 1062 disasters in
this period were the result of floods and tropical cyclones,
whereas 52% of disasters in 2007 were related to the
weather. Most susceptible are those populations living in
developing nations that occupy coastal tropical regions.
70% of natural disasters between 2004 and 2006 occurred
in Asia, the Pacific region, Africa, and the middle east,76
where most of the world’s vulnerable and exposed
populations reside. As defined by the reinsurance group
Munich Re, in 2007 there were 960 major natural
disasters (the highest ever such figure),77 with more than
90% being the result of extreme weather-related or
climate-related events, together accounting for 95% of
the 16 000 reported fatalities and 80% of the total
$82 billion economic losses.
Of the 238 great natural catastrophes that occurred
between 1950 and 2007, two-thirds resulted from extreme
weather or climate-related events, mainly floods and
windstorms.77 According to Munich Re,77 the number of
great weather-related disasters has climbed from an
average of less than two per year in 1950 to more than six
in 2007. Over the same period, average annual economic
losses have risen from less than $5 billion to more than
$60 billion.
According to the IPCC fourth assessment report,4 the
frequency of heavy precipitation events has increased
over most land areas; more intense and longer droughts
have been observed across wide areas since the 1970s;
widespread changes in extreme temperatures over the
past 50 years have seen less frequent cold spells and
more frequent and intense heatwaves than ever before;
intense tropical cyclone activity has risen in the north
Atlantic since about 1970; and the incidence of extreme
high sea levels has also risen.
Observed climate-related hazard trends are held by the
IPCC to be likely or more likely than not to indicate
human contribution.4
On the basis of projections for the 21st century with
special report on emissions scenarios,78 the frequency of
most meteorological extreme events is expected to
continue to rise.4 Hot conditions, heatwaves, and heavy
precipitation events will continue to become more
frequent.4 According to Sterl and colleagues,79 by
2100 northeast India and Australia can expect summer
temperatures to peak over 50°C, and the southwest,
central west, and southern Europe over 40°C. This
warming is expected to have serious health implications
for vulnerable groups such as elderly people with
cardiovascular conditions. Precipitation intensity is
predicted to increase across most regions,1 which could
result in increased river and flash flooding, including
those related to the south Asian monsoon.80 Although the
total number of tropical cyclones might decrease, more
powerful, and therefore potentially more destructive,
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storms could become increasingly frequent.81 Future
trends in extratropical storm activity remain difficult to
predict, but a consensus exists that changes will become
apparent. Ulbrich and colleagues82 forecast increasing
storm-track activity in the eastern north Atlantic, western
Europe, and parts of Asia, which might intensify extreme
cyclones. Jiang and Perrie83 predict that Atlantic
middle-latitude storms will increase in radius and tend to
become more severe and faster, whereas Rockel and
Woth84 estimate a future increase of up to 20% in the
number of storm peak events over central Europe. Coastal
flooding arising from powerful storms causing high
storm surges are projected to increase. According to the
IPCC fourth assessment,1 this event could triple (from
the current 200 million) the number of people vulnerable
to extreme surges.
Population and migration
Population growth will interface with climate change in
ways that intensify several other mechanisms, especially
shelter, food, and water scarcity. Population growth also
puts additional stress on already weak health systems
and exacerbates vulnerability to the adverse health
effects of climate change. Independent of population
growth, large-scale population movement is likely to
intensify as changing climate leads to the abandonment
of flooded or arid and inhospitable environments. The
resulting mass migration will lead to many serious
health problems both directly, from the various stresses
of the migration process, and indirectly, from the
possible civil strife that could be caused by chaotic
movement of people.
According to the UN 2006 revision of the world
population prospects, the world population is likely to
increase from the current 6·7 billion to 9·2 billion in
2050.85 This increase is equivalent to the total global
number of people in 1950, and it will be absorbed mostly
by the less developed regions, whose population is
projected to rise from 5·4 billion in 2007 to 7·9 billion in
2050. By contrast, the population of developed regions is
expected to remain mainly unchanged at 1·2 billion, and
would have declined if it was not for the projected net
migration from developing to developed countries, which
is expected to be 2·3 million persons every year after
2010. Modest changes in fertility have large effects on
population growth. Current projection is that the world
population will grow to 9·2 billion by 2050 but, if fertility
is half a birth higher or lower than that expected between
2005 and 2050, the world population will be 10·8 or
7·8 billion, respectively, in 2050.85 Furthermore the
current median projection assumes that fertility will
continue to decline, which is threatened by the reduction
in funding over recent years for family planning
services.
Population growth will increase pressure and
competition for scarce resources, such as food, water,
and land. To compensate, production will rise, resulting
in even greater environmental degradation of arable land.
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Both demand and compensatory rises in food production
will be complicated by high land loss, a result of
industrialisation, urbanisation, and sea level rises and
increased flooding. Also, an expansion of the global
population will eventually bring a substantial rise in CO2
emissions.
Rising sea levels, which result from oceanic thermal
expansion and ice-cap melting, will be a major
contributing factor to population displacement.4 The
recent doubling of sea level rise projections from the
March, 2009, Copenhagen conference are especially
worrying. As mentioned previously, a third of the world’s
population lives within 60 miles of a shoreline, and a
high number of these live at low altitudes. The rising of
the sea level will be most intensely felt in densely
populated, low-lying river deltas, such as the delta region
of Bangladesh or the Nile delta in Egypt. In Bangladesh,
for instance, over 120 million people populate the
complex delta region: a 0·5-m sea level rise will account
for 10% land loss and a displacement of 6 million people;
a rise of 1·0 m will cause 20% land loss and a population
displacement of 15 million people.86
Drought and desertification frequency and intensity
will increase, causing health problems and also
influencing population migration. Droughts, especially
in rural areas, have a tendency to affect migration into
cities,1 increasing urbanisation and stressing the socioeconomic
conditions already exacerbated by high
population growth. It is estimated that 72% of the
dwellers in African cities live in slums, which, having
poor drainage facilities, are especially prone to flooding
and ill health.87 Action Aid ran analyses of slum dwellers
in six African cities and found intracity flooding and the
consequence on hygiene and sanitation to be a major
health concern.88
Although it is impossible to predict with any certainty
what climate change will mean for human population
migration,89 the number of climate-change-related
migrants that could exist by 2050 is estimated to be in the
hundreds of millions.90
Climate change, population growth, migration, and
conflict are contentious issues. Climate change might be
one of many factors influencing violence,91 but where
conflict occurs between migrant and host populations, it
is a result of national identity clashes rather than of
migration.92 This association, however, has been observed
for example in Darfur. Coinciding with warming of the
Indian ocean, average rainfall in southern Sudan
dramatically fell in recent decades, prompting the UN
Environment Programme to recognise that climate change
and desertification have been an additional stressor to the
population, influencing migration to the south and thus
might have contributed to the initiation of the conflict.93
A policy response framework
Climate change is a real threat to global health and
wellbeing, and is contributing to mortality, especially for
people living in poverty and lacking access to essential
health care. A 2°C rise will result in insecurity for millions
of people in terms of food, water, or shelter, with the risk
of many additional deaths.
No countries will be immune from the health effects of
climate change. For example, the hurricane Katrina in
the USA and the deaths caused by the 2003 heatwave in
Europe show that rich countries cannot always protect
themselves from the adverse health consequences of
climate-related events.
An integrated approach to attempting to reduce the
adverse effects of climate change requires at least three
levels of action. First, policies must be adopted to reduce
carbon emissions, and thereby slow down global warming
and eventually stabilise temperatures. Second, action
must be taken on the links connecting climate change
and adverse health. Third, appropriate public health
systems should be put into place to deal with adverse
outcomes.
Slowing down carbon emissions presents daunting
challenges, requiring coordinated action on a global scale
(panel 2). However, many adaptation strategies can be
pursued by a combination of local, national, regional,
and global strategies, and hence important steps can be
taken requiring less demanding forms of cooperation
and therefore with greater speed. This does not mean
that adaptation will be easy or straightforward. Common
challenges exist that make, and will make, the process of
Panel 2: International law on climate change
The agreement of the UN Framework Convention on Climate
Change (UNFCCC) in 1992 was the first major step in the
development of international law on climate change. This
agreement, which provided only minor targets and
ambitions, crucially puts in place institutions and procedures
for global debate and action on climate change. It also set the
stage for the more ambitious Kyoto protocol in 1997, which
aimed to cut developed-country greenhouse gas emissions
by 5% below 1990 levels in 2008–12. The protocol provided
for three market-based mechanisms (emissions trading, clean
development mechanism, and joint implementation) to
contribute to emission reduction. Within the overall
5% target, the obligations of individual developed countries
vary greatly. Developing countries undertook no emission
reduction targets in Kyoto, and the USA did not ratify the
protocol. In the recent meeting in Poznan (Poland),
discussions focused on an ambitious response to climate
change mitigation that would include targets for the large
developing countries, such as China, India, and Brazil. The
negotiations on the Kyoto protocol’s adaptation fund were
also moved forward. The fund is a legal entity that provides
grants to help developing countries to adapt to the
consequences of climate change. International negotiations
to set targets beyond 2012 are ongoing, and will be
concluded in Copenhagen at the end of 2009.
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adjustment to climate change difficult. Here, we highlight
five overlapping challenges. These are not the only five
and they might not even be the most important. Our goal
is simply to promote creative thinking on how to respond
to them.
Informational challenge
The generation of reliable, relevant, and up-to-date
information will be essential to respond to the negative
health effects of climate change. Information is worthless
without political will or institutional capacity; however,
without information, political will or institutional capacity
will achieve little. This challenge is about the generation
and dissemination of relevant information about the
public health effects of climate change and how to
address them. In developed countries, at least, general
awareness of the issue seems well established. Yet, much
more detailed and specific information is necessary if an
intelligent response is to be made. Information pertaining
to specific regions, countries, and localities is an
important resource, which is not yet sufficiently available
for poor countries.17 Building the capacity of governments
and universities in the poorest countries could take a
long time to accomplish, therefore new operational
systems for vulnerability assessments are needed
especially in Africa and Asia. South America and
Caribbean countries have done much to assess the effect
of climate change, but a lot remains to be done.
WHO has identified key gaps in knowledge—notably, a
lack of region-specific projections of changes in
health-related exposures and a lack of research on health
outcomes concerning various future emissions and
adaptation scenarios. WHO has also noted the issues of
models that generalise health outcomes between
locations because important local factors, such as transmission
dynamics, might not be well captured.
Varying capacity for research and adaptation in
low-income and middle-income countries is likely to
deepen the inequality of health effects. The geographical
distribution of the 16 national health impact assessments
of climate change done between 2001 and 2007 is
indicative. Only five assessments were in low-income or
middle-income countries—India, Bolivia, Panama,
Bhutan, and Tajikistan—and none were in Africa. Local
capacities for research must be strengthened with local
responses to climate change.
Little modelling has been done outside developed
countries despite the effects on health being skewed
towards developing countries. Information that is reliable,
accurate, and disseminated is fundamental for effective
adaptation and to avoid the so-called adaptation apartheid.
For example, heatwaves are silent killers. Although we
have good data for the effects of heatwaves in the USA
and Europe, almost no reliable data for heatwave-induced
mortality exist in Africa or south Asia.94,95 Disease
monitoring, surveillance, and health early warning
systems depend on reliable information provided by
meteorological stations worldwide. However, the number
of these stations in Africa, for example, is eight times
lower than the minimum recommended by the World
Meteorological Organisation, and reporting rates are the
lowest in the world.96 A key challenge is the financial and
technical constraints that prevent developing countries
from wide-scale implementation of these stations.14
The 61st World Health Assembly resolution—passed
unanimously in May, 2008—lays out five priorities for
research and action: extensive documentation of the risks
to health and differences in vulnerability within and
between populations; development of health protection
strategies; identification of health co-benefits of actions
to reduce greenhouse gas emissions or to adapt to climate
change; development of decision support systems to
predict the effects of climate change for member states;
and estimation of the financial costs of action and
inaction.
Better modelling of basic climate–health association
and a comprehensive assessment of current and future
climate-related burdens of disease are needed. Some
climate–health associations cannot be formally modelled
(eg, mental health or infectious disease consequences on
population displacement), therefore alternative qualitative
and longitudinal studies will be needed.97
Assessment of the burden of disease associated with
climate change is challenging because of the unusually
wide range of health outcomes (and inputs) affected.16
However, detailed estimates are essential both in
strengthening understanding of the consequences of
failed attempts at emission mitigation and in formulating
policies to improve adaptation in those most at risk.
The challenge to disseminate information is about
ensuring that the necessary information is available and
easily accessible in the right place at the right time.
Mechanisms to ensure that the lessons of experience and
experiments in one place can be learned in other, perhaps
distant, places are essential. Several databases have been
established to facilitate learning, such as the UK Climate
Impacts Programme database (panel 3) and the UNFCCC
database on local coping strategies. It gathers and
disseminates knowledge and experience from
communities that have had to adapt to specific hazards
or climatic conditions.100 It is searchable by hazard (eg,
floods), outcome (eg, decreased food security), and
strategy (eg, appropriate crop selection), and new case
studies can be added. The current examples come from
various developing countries, including China. There are
a few contributions from developed countries, such as a
heatwave strategy in Philadelphia (USA) and typhoon
preparedness in Japan.
Policy responses to the public health effects of climate
change will have to be formulated in conditions of
uncertainty. The complexity of uncertainty partly
indicates that climate change is not a stand-alone risk
factor but, rather, an amplifier of existing health risks.
The unavoidability of uncertainty refers to the unusual
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future projection of health risks, and not something
that is much, if ever, done in routine environmental
epidemiology and public health. Therefore, uncertainty
will always exist about the scale and timing of the
effects, as well as their nature, location, and intensity.
Regardless of any lack of clarity about what the
precautionary principle means (panel 1), action will
have to proceed in spite of scientific uncertainty. Policy
responses must be able to adapt to new information or
unexpected events.
Changing patterns of disease and mortality
A fundamental requisite for health adaptation to climate
change is to improve monitoring and surveillance of
disease and mortality in sensitive regions. In developing
countries, disease surveillance systems are inconsistent
and poorly managed. The challenge is to incorporate a
strong public health infrastructure and empower
communities to achieve effective disease surveillance.
Health early warning systems are especially important
in the context of heatstroke, extreme weather events, and
disease outbreaks for developing and developed countries.
The effectiveness of health early warning systems
depends on the past and current disease monitoring and
surveillance, and accurate and reliable meteorological
and climatic forecasts. Health early warning systems are
a win-win strategy that reduces the risk of disease whilst
increasing adaptive capacity that is most essential in the
context of developing countries.
In the developing world, no region-specific projections
of changes in health-related exposures and no research
projecting health outcomes under various future
emissions and adaptation scenarios compared with many
parts of developed countries exist.1,101 Recent reports have
highlighted the urgent need for improved surveillance
systems and technologies, especially for infectious
diseases in developing countries and for increased
cooperation between states in the identification and
public health response to outbreaks and epidemics.102
Food
Prediction on how climate change will affect agricultural
production is lacking. Some of the negative effects of
climate change on agriculture could be offset by better
practices, more irrigation, and use of genetically modified
crops. However, in some areas a complete change of
agricultural practices and type of crops grown will be
needed. This is both an informational and social
challenge. With climate change, many areas might
become unsuitable for cash crops; however, because of
market forces, high use of irrigation and pesticides might
still make it financially viable. But the land might be
more suitable and more environmentally sustainable if
used for mixed food crops. These important decisions
need information to ensure a region’s or country’s food
security in spite of climate change.
One suggestion of multinational biotechnology corporations
and some governments is that the effects of
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climate change on food can be dealt with by technological
solutions, especially genetically modified plants. This
idea places a corporate, technological, and commercial
approach against one that questions the claims that
genetically modified plants will increase food security
and be able to cope with climate change, and that instead
calls for more ecologically sustainable forms of farming
that will also provide direct benefits to organisations of
small-scale farmers, fisherfolk, and indigenous people,
while strengthening national food sovereignty in poor
countries. The 2008 international assessment of
agricultural science and technology for development
(also known as the world agriculture report), which was
written by over 400 scientists and is similar to the reports
of the IPCC, states: “To address expected climate change
challenges and impacts, a major role for agricultural
knowledge, science and technology is to increase
adaptive capacity and enhance resilience through
purposeful biodiversity management. Options include
irrigation management, water harvesting and
conservation technologies, diversification of agriculture
systems, the protection of agrobiodiversity and screening
germplasm for tolerance to climate change”.103 It also
states that there is no evidence that genetically modified
plants will increase food security in a changing climate
and indicates some dangers related to an over-reliance
on such plants.103
Water and sanitation
At present, water resource and infrastructure management
have been based on data for a stable climate.71 No
assessment exists on how effective currently recommended
interventions (from hygiene promotion to
infrastructure) will be in a different climate. The key
issue with the management of water in the future is not
only that climate change predictions are uncertain but
also that the climate will be unstable and unpredictable
on the basis of long-term historical data. Water-resource
managers and policy makers need to shift from
risk-based approaches based on historical climate and
hydrological data to decision making in an uncertain
setting. Improved data collection and modelling will
provide useful ways to guide decision making, but the
nature of decision making under climate change will be
fundamentally different.
The quality and availability of data and climate
models are variable worldwide. This variability poses
substantial challenges in understanding regional
climate systems to improve climate and hydrological
modelling. Improved observation and modelling of
climate and hydrology are a challenge, especially for
developing regions including Africa, Asia, and South
America. Observation and modelling are needed to
provide baseline scientific input for planning and
managing water resources and infrastructure.
Furthermore, policy makers are faced with the issue
that water scarcity indexes currently only include
surface water. Many populations rely on ground and
stored water resources, which are not currently taken
into consideration.104
Shelter and human settlements
There is growing evidence, through simulations and
empirical studies, that human settlements, both rural
and urban, will be greatly affected by the irreversible
outcomes of climate change, even in the most optimistic
scenarios.105 Research and debate should focus on how
settlements will be affected and how to best adapt to
climate change.14 The social and economic effects of
climate change will increase inequalities worldwide.
Most vulnerable people live in urban settlements in
developing countries that have limited resources to
adapt to climate change and are already affected by
several natural-related risks, such as floods and
landslides.106,107 Paradoxically, urban areas in high-income
nations, which are the greatest contributors to
greenhouse gas emissions, have much more resource
capacity to adapt. Climate change debates on urban
settlements tend to be focused on mitigation and,
consequently, are limited.
Extreme events
Better assessment of the health effects of extreme
climatic events requires improved modelling of their
pace and spatial distribution and more thorough and
sophisticated models of the demographic, social, and
economic trends that increase human vulnerability to
hazards. Also, adaptation and mitigation will require a
new approach to management of extreme events,
focusing on improved early warning, effective
contingency planning, identification of the most
vulnerable and exposed communities, and, in some
cases, permanent resettlement. Such challenges are only
likely to be met successfully where disaster risk reduction
is actively incorporated as a mainstream activity of social
and economic development.108
Panel 3: The UK climate impacts programme
The UK experience offers a positive example for generating
local information about climate change adaptation. The UK
climate impacts programme (UKCIP) is mainly funded by the
UK Government through the Department for Environment,
Food and Rural Affairs (DEFRA). Its aim is to provide
information through models and interactive systems for
stakeholders in the UK. At present, UKCIP is a unique global
resource helping individuals, companies, and governments
to assess their vulnerabilities and to build adaptation
strategies. Similar programmes, if copied by other countries,
would help policy makers to design adaptation policies. The
models can predict decadal changes in water and food
security, extreme events, as well as changes in the extent of
potential disease vectors.98,99
For more on UKCIP see http://www.
ukcip.org.uk/
For more on DEFRA see www.defra.
gov.uk/environment/climatechange/
uk/ukccp/pdf/ukccp-annreport-
july08.pdf
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Current knowledge of the health effects of extreme
events is limited by scarce (especially related to
subjectivity) data collection and analysis, and
epidemiological and longitudinal studies.109,110 Two
principal challenges can be identified: first, expansion
of knowledge of the factors making populations
vulnerable through improved climate modelling and
vulnerability assessments at the regional and local
scale; and second, identification of the most appropriate
actions and approaches for reducing extreme-event
disaster risk and, consequently, limiting resulting
health effects.108,111
Population and migration
The connection between population growth and climate
change is complex; because the main cause of climate
change lies in the rate of carbon emissions in developed
countries, developing countries cannot be blamed for the
issue of population growth. However, developing
countries with rapid population growth might become
substantial contributors to climate change.
Accurate models of the number of environmentally
displaced people because of uncertainty of the effects of
climate change are not feasible. The association between
climate change and migration is complex, and environmentally
induced migration should be viewed as a
consequence of a multicausal system that includes
political, social, and economic factors.112 Similar to
migration, the association between climate change and
conflict is difficult to quantify. Climate change is not the
only factor leading to migration or violence but high
population densities and growth, inequality, and
underdevelopment are also responsible.113
For example, the effect of rising sea levels on
migration is uncertain, as sea level rise does not only
depend on the rate of global temperature rise but also
on the rate of natural processes such as subsidence.
The World Bank has estimated that, by the end of the
21st century, the sea level in Bangladesh could rise by as
much as 1·8 m. In the worst-case scenario, they
estimated that this would result in a loss of up to 16% of
land supporting 13% of the population and producing
12% of the GDP.3
Investment in voluntary family planning programmes
can make a great contribution to mitigation and
adaptation programmes. Policy formulation to develop a
new plan that combines reduced child mortality with
access to family planning will be a major challenge.
The challenge of poverty and inequality
Many of the most serious public health consequences
of climate change will be experienced by the world’s
poorest nations, increasing global health inequities.20
Basic infrastructure for much of the world’s population
is inadequate to meet essential health care needs, and
our ability to cope effectively with the aftermath of
natural disasters is insufficient. Overall, all the
underlying social, economic, and ecological
determinants of global illness and premature death will
be exacerbated by climate change.20 Progress towards
the Millennium Development Goals and achievement
of the 2015 targets might be impaired or reversed.
Because climate change acts mostly as an amplifier of
existing risks to health, poor and disadvantaged people
will experience greater increments in disease burden
than rich, less vulnerable populations.24,26
The current financial crisis raises doubts about a
global model to reduce inequities based on economic
growth. Contraction and convergence (panel 4) increase
the need for new economic approaches, which place
sustainability and equity at the centre of the economic
debate.115
Nobody doubts that efforts to adapt to the negative
health effects of climate change will be expensive. Even
the conservative UNFCCC estimates that by 2030 tens of
billions of dollars every year will be required to meet the
costs.116 Funds dedicated through international bodies
are much less than these estimates.117
UNFCCC funds aim to reduce vulnerability to climate
change and to help build adaptive capacity. These are very
modest relative to need, being around $275 million. The
Kyoto adaptation fund, managed by the Global
Environment Facility is larger.118 However, even the most
optimistic estimates predict that the fund could yield
only $1–5 billion every year. Even if the same amount
could be contributed by the World Bank’s new climate
change funds, it would not be enough.119
Additionally, the adaptation fund is not yet operational,
and developing countries are unhappy about the
management of existing funds.
Not only is raising more funds to support adaptations
to climate change needed, but also ensuring appropriate
management and control of this finance internationally,
and by national and local governments. Although
redistribution through government aid and fiscal policy
is crucial, private funds and private investment are also
important in funding climate change adaptation.
Panel 4: Contraction and convergence
Climate change requires two possibly conflicting actions.
Carbon emissions must be reduced to avoid the worst
outcome of climate change. Poor countries need rapid
economic development so that no country, community, or
individual is too poor to adapt to climate change. The concept
of contraction and convergence, developed by the Global
Commons Institute, considers the need to pursue both these
actions simultaneously.114 Contraction and convergence reduce
overall carbon emissions to a sustainable level but do so
according to an equal share of emissions per person globally.
Industrialised countries would dramatically reduce their
emissions whilst developing countries would increase theirs to
allow for, and stimulate, development and poverty reduction.
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Patterns of disease and mortality
Poor people are greatly affected by disease worldwide.
Whether in a developed or developing country, health
outcomes are worst for those on low incomes20 because
they lack access to the health system. HIV/AIDS,
tuberculosis, and malaria have perpetuated poverty in
developing countries because of the cost of treatment
and the loss of productivity.
Infectious and vector-borne diseases related to climate
change will have their greatest effect in resource-poor
settings through poor housing, poor water supplies and
sanitation, and increased vulnerability.
Gender inequity is another important factor. In
developing countries, women are among the most
vulnerable to climate change; they not only account for
a large proportion of the agricultural workforce but also
have few alternative income opportunities. Women
manage households and care for family members,
which limit their mobility and increase their vulnerability
to natural disasters and other local sudden climate
changes. Efforts to keep the adverse effects of climate
change to a minimum should ensure that policies
address issues of women’s empowerment.
Individual assets that bring benefits to a woman’s
family and community, such as health and education,
are easily attainable with good reproductive health. In
particular, adequate birth spacing improves maternal
and infant health and resilience, and contributes
significantly to women’s ability to be economically
productive. Gender differences must be taken into
account not just in terms of differential vulnerability but
also as differential adaptive capacity. During a natural
disaster, for example, women have a key role in
protecting, managing, and recovering lost household
resources, and often develop innovative strategies to
address climate change.120 Case studies in Senegal,
Bangladesh, and Ghana showed grassroots women’s
groups developing strategies to cope with issues related
to energy and forestry, agriculture, water resources, and
trade. Women should be perceived as powerful
contributors of change and should be fully integrated
into climate change mitigation and adaptation strategies
at all levels.
Vulnerability will exist to both climate change and
poverty, especially in developing countries.121 The
vulnerability of poor people to climate change is
manifested in three main ways: exposure, sensitivity, and
adaptive capacity. The world’s poor nations are exposed
to the effects of climate change due to their geographical
location.122 Also, low education, income, health, and other
contextual factors reduce the adaptive capacity of
developing countries. Therefore, future vulnerability to
the health effects of climate change depends on
development and climate change itself.
The challenge is to reduce not only poverty but also the
diseases related to poverty, such as water-borne and
vector-borne diseases, which require sustainable
development with a functioning primary and secondary
health system. This challenge should be underpinned by
a strong public health infrastructure, incorporating
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surveillance and monitoring of diseases, access to
technologies at an affordable cost, access to health
professionals, access to health centres especially in rural
areas, and sustainable education and training of future
health professionals.
The limited research and structural adaptation in
low-income and middle-income countries are likely to
deepen social inequality related to climate change. Public
sector financial constraints and national infrastructure
and human capacity should be improved.
Food
The present structure, organisation, and control of the
globalised food and agricultural system are failing to
address the needs of both poor people and the
environment. For example, profits of giant agricultural
and food corporations increased greatly in 2008, when
the number of hungry people grew.123,124
Most farms are smallholder operations of less than
2 hectares. 0·5% of world’s farms that exceed 100 hectares
claim a disproportionate share of global farming income,
enjoy privileged access to land and policy makers, and
receive a share of tens of billions of dollars of public
subsidies every year.125
Direct payments to farmers of the Organisation of
Economic Cooperation and Development amounted to
$125 billion in 2006. For the past 25 years, many
low-income countries had to adopt trade and agriculture
reforms, including: dismantling or privatisation of public
instruments such as marketing boards, farmer credit
schemes, input subsidies, and extension programmes;
shifting from food to export crops; and opening up to
competition with the heavily subsidised agricultural
businesses in developed countries.61 At the same time,
development assistance to the agricultural sector has
fallen. The aid of the Organisation of Economic
Cooperation and Development to farmers in developing
countries was only $3·9 billion in 2006, and now accounts
for 3·4% of aid budgets, even though 75% of the world’s
poor people live in rural areas.
Water management will be crucial to future food
security.126 Co-management of water for agriculture and
ecosystems is a precondition for ecological sustainability,
requiring ways to value water socially, economically, and
ecologically.
Geographic, satellite, and food price monitoring have
an important role as early warning systems for famine
and food insecurity, but a functioning primary health
care system is probably the best and most effective way.
Water and sanitation
Climate change requires urgency to deliver water,
sanitation, and drainage to the world’s poor nations,
which need fair financial and regulatory mechanisms,
allowing for delivery of affordable services whilst
providing resources for construction, maintenance, and
operation of water and sanitation systems. Public,
private, and community sectors are important in
providing specific systems and delivery services locally.
River basins and water catchment areas that cross
political boundaries require policies and regulations to
provide fair access to water resources and to avoid
conflict.
Access to good primary health care is essential for
populations vulnerable to climate change, also for
water-borne diseases. People who are in good health are
less likely to be vulnerable to water-borne diseases
during extreme events. Good primary health care will
not only improve the resilience of local populations to
water-related and sanitation-related diseases but also is
the best early warning system for epidemics of
water-borne diseases.
Shelter and human settlements
Reductions in poverty, including improvements in
housing and living conditions, and in provision for
infrastructure and services, would reduce climate change
hazard vulnerability. Moreover, an articulation of the
brown and the green agenda perspectives in dealing with
human settlements could reduce vulnerabilities and
mitigate climate change.127 For example, reforestation
and afforestation can reduce risks of flooding. Indirect
effects on settlements (eg, health, lack of water, migration,
and livelihoods) and how urban dwellers develop
mechanisms to cope with these effects need to be
assessed to understand how these mechanisms could be
mainstreamed into urban planning responses to climate
change adaptation.128
Current risks linked to climate change and variability
are due to the large proportion of urban dwellers lacking
protective infrastructure and little land-use planning.
When buildings and infrastructure are developed in
urban centres, environmental effects are often not taken
in consideration. These are responsibilities of local
governments, whose institutional capacity varies widely.
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Those settlements with little economic diversification—
where most income comes from climate-sensitive
primary resource industries such as agriculture, forestry,
and fisheries—are more vulnerable than diversified
settlements. 99% of households and businesses in
low-income countries do not have disaster insurance.129
As climate change intensifies, the housing issue (eg,
affordability and availability) is aggravated both in
developed and developing countries, mostly affecting
poor people.
With half of the population of urban centres in
low-income countries lacking piped water, waste
collection, paved roads, sewers, and storm drains, their
vulnerability has not been reduced by existing
mechanisms that focus on social and economic
development.73 With persistent vulnerability, poor people
living in urban areas are more susceptible to increasing
frequency and intensity of climate change.
Extreme events
An effective assessment of the increasing climatechange-
driven extreme events requires that national
governments embrace the idea that natural disasters are
related to the particular societal context within which
these events take place. In other words, those affected
are in a position of risk as a consequence of a portfolio of
economic, social, and political institutional factors that
can and should be addressed by decision makers.130
Control of climate-change-related extreme events has to
be achieved through developmental and humanitarian
responses, and through increased preparedness and
response that come from integrating the disaster risk
reduction paradigm (defined by the UN international
strategy for disaster reduction as “the broad development
and application of policies, strategies and practices to
minimise vulnerabilities and disaster risks throughout
society”) with a nation’s future development.108,111
Population and migration
Because contraceptive use in a population is the major
determinant of birth rate and hence population growth
or decline, family planning is not just an adaptation to
climatic change but also a mitigation strategy to achieve
a sustainable population (panel 5). The predicted
population increase is unsustainable and will severely
exacerbate the issues of urbanisation in developing
nations. Obstacles to effective use of family planning are
complex, but much experience exists in providing family
planning services that can meet the needs of about one
in six women worldwide who want to delay or cease
childbearing but cannot access effective contraceptive
methods. According to the UN Population Fund, many
women in every country report that their last birth was
unwanted or mistimed.
The 1994 international conference on population and
development in Cairo (Egypt) emphasised the importance
of reproductive health and of empowering women to take
charge of their reproductive lives. The poorest people
have the least access to, and greatest need for,
contraceptive services; however, since 1994, funding for
family planning programmes has been reduced, partly
because of the diversion of funds to HIV/AIDS.
Additionally, US Agency for International Development
(USAID) funds under Republican administrations have
been subject to the gag rule, which stipulated that, to be
eligible for USAID funding, an organisation could not
spend any funding from any other source on
abortion-related activities. This rule was repealed by
President Obama in early 2009, so family planning
service delivery is hoped to improve in the future in the
poorest countries.
The technological challenge
The UNFCCC identifies technology transfer (along with
funding and insurance) as key actions for adaptation to
climate change by developing countries. Appropriate
technologies are adapted to local economic and
ecological conditions, and take into account local
knowledge, skills, and culture. The technological
challenge is not only about high-technology solutions
but also about understanding biodiversity to develop
appropriate policy responses, and the contribution that
less developed communities can make in sharing their
knowledge of sustainable low-carbon technologies and
ways of life.
Technological challenge requires incentives for the
development of technologies needed to address the
negative public health consequences of climate change
in poor countries. Experience in the pharmaceutical
sector has shown that rich markets generate vigorous
research and development activities, whereas poor
markets are mainly ignored. Public funding for
investment in developing technologies for poor markets
Panel 5: Family planning
Family planning is a unique solution among medical
interventions. It reduces poverty, and maternal and child
mortality; increases primary schooling, and women’s
education and empowerment; increases environmental
sustainability; and mitigates the effects of climate change
through stabilisation of global populations. Family
planning is not simply about technology; female literacy
and education should be as important as the provision of
family planning services. Although the issue of climate
change is mainly due to high consumption and greenhouse
gas emissions in developed countries, population growth is
highest in developing countries where it will compromise
efforts to achieve sustainable development and the
transition to low-carbon economies. We can neither reverse
environmental degradation nor respond to the health
challenges presented by climate change in a context of
continuing rapid or even moderate population growth.
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is required. Furthermore, although intellectual property
rights have a role in rewarding innovation and scientific
discovery, most people realise that these can also hinder
scientific development by reducing sharing of knowledge
and lead to excessive prices. Technological challenges
require a rebalancing of the benefits and costs of the
current intellectual property regime. Currently, the
World Trade Organisation’s agreement on trade-related
intellectual property rights has put in place a global
system for patent protection for a minimum period of
20 years. The exceptions in the agreement are not
sufficient to accommodate the needs of poor countries
with limited capacities to produce their own versions of
patented technologies. Therefore, a waiver has been
agreed to facilitate access to essential medicines for poor
countries.131 Although the framework is in place, the
waiver has been relied upon only once by Rwanda in the
5 years since its adoption. Serious efforts need to be
made to ensure that intellectual property protection does
not constitute an impediment to climate change
adaptation in poor countries.
The technological challenge also requires development
of knowledge in poor countries. The educational and
scientific base of a country will have an important role in
increasing or constraining any individual country’s
capacity to adapt. Because of the scale and complexity of
the technological challenge, and its many dimensions,
fostering multidisciplinary collaborations to capacitate
development in all areas will be essential.
Patterns of disease and mortality
No effective vaccines exist for many climate-sensitive
communicable diseases (eg, malaria, dengue fever,
schistosomiasis, and leishmaniasis). The international
community must promote research and development for
vaccines that can be made accessible to the most
vulnerable people. They must also find a sustainable and
ethical solution to the trade-related intellectual property
rights (TRIPS) agreement that allows developing
countries to buy medical supplies without a substantial
burden on their budgets. Large-scale vaccination
programmes in the developing world would also require
a strong public health infrastructure, knowledge, and
finance and political will.
Low-cost and low-technological solutions, such as
mosquito nets and water filters, provide effective public
health systems for responding to health effects of climate
change.
Satellite mapping and geographical information systems
are useful analytical ways for local, regional, and national
surveillance to project future health outcomes. For
example, such systems for malaria in the developing world
could allow health-care professionals to reallocate
resources and prevent predicted future outbreaks.
However, to maximise the effect of this technology
requires accessibility of finances, knowledge, and expertise
in poor countries. Existing or new technologies to reduce
the effects of climate change on health cannot create
secondary negative outcomes or contribute to further
climate change. For example, air conditioning units can
be introduced in homes, offices, and public buildings to
reduce risk from heatstrokes. However, air conditioning
units are highly energy inefficient and contribute to
climate change, therefore producing an adverse secondary
effect. New technology should aim to be carbon neutral,
inexpensive, and easily manufactured worldwide.
Food
The technological challenge in this area is to ensure food
security mainly by environmentally friendly ways of
increasing food availability. Future temperature rises
might have an especially strong effect in tropical regions
because crops grown there are less resilient to changes in
climate than those grown in non-tropical regions. A
major technological challenge is to develop new crops to
withstand higher temperatures.65 The key task, attuned to
local culture and economy, is to find ways of lessening
adverse health risks from changes in food yield, quality,
and accessibility.
Although industrialised and intensive agricultural
production has helped to boost food output, it has also
undermined the integrity of ecosystems by, for example,
impairing nutrient cycling in soils, overusing pesticides,
and disrupting natural pollination. Such sustained high
agricultural output has also depended on fossil fuel use
to generate fertilisers. Agricultural mismanagement can
also result in salination and water-logging of soils, and
in land degradation and soil erosion.132,133
Technological changes in agriculture will also be
important for climate change mitigation. Agricultural
practices and aspects of the current global food system
are major contributors to global warming. Agriculture
has been estimated to be responsible for 14% of total
greenhouse gas emissions. According to the International
Food Policy Research Institute and the Food and
Agriculture Organisation, agriculture, land use, and
waste account for 35% of greenhouse gas emissions.60
The major causes are the production and use of
fertilisers; methane production from wetlands (especially
Panel 6: Changing consumption patterns137
Governments should not simply indicate public preferences
but also offer leadership in shaping public priorities on
important issues. Global political leadership has paid too much
attention to the need for consumption-led economic growth
and too little to issues of equity and fulfilment of basic rights.
Global taxation and trade regimes foster a global culture that
results in a global luxury market of cosmetics of around
US$25 billion (which is part of a broader cosmetics market
worth $200 billion) and a global pet-food market projected to
grow to $40 billion by 2010. This spending would comfortably
fund basic social protection for low-income countries.
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rice production) and methane emissions from livestock;
and carbon released from deforestation and land
clearance. Global increase in consumption of meat and
dairy products also augments methane production.
Furthermore, the global transportation of food causes
additional greenhouse gas emissions.
Water and sanitation
Less than 4% of Africa’s groundwater resources are
currently exploited. Although climate change threatens
accessibility to water resources in general, the magnitude
of this threat could be reduced with the development and
availability of appropriate technology to exploit
groundwater resources. Approaches to provide access to
safe drinking water and sanitation have conventionally
followed either large-scale, centralised infrastructure
systems or small-scale, locally affordable, and
maintainable technologies. Resilience to climate change
might require new approaches that provide the universal
public health benefits of large infrastructure systems
while avoiding high water consumption at a cost that is
affordable for all. Water and sanitation systems need to
be appropriate to local geography, culture, knowledge,
and resources, and able to withstand high intensity
rainfalls and drought conditions, and keep wastage of
clean water to a minimum. Ecological sanitation systems
and low or no flow toilets that do not require water to
dispose human waste safely are likely to be of increasing
importance in delivering good public health outcomes
under water-scarce conditions.
Systems for safely storing and treating water and
technologies for using alternative supplies of water, such
as waste-water recycling and desalination, are also likely
to be important, although the development and implementation
of these systems might undermine climate
change mitigation efforts if they result in increased
carbon emissions. Urban drainage systems, which
incorporate principles of sustainable design (such as
rainwater harvesting), will provide resilience to high
rainfall events while removing standing water that can
become contaminated, and act as habitat for vectors such
as mosquitoes. Water and sanitation technologies, which
can be easily deployed during emergency situations, such
as floods or hurricanes, will be increasingly important.
Water-conserving technologies, which deliver good
public health outcomes but consume little water, will
need to be implemented greatly in households and
settlements. Design and management of water and
sanitation infrastructure need to account for resilience to
droughts and floods, and changing annual average
rainfall.
For example, the IPCC has compiled data for
technological adaptations that have already been
implemented in areas of Africa aimed at promoting
climate resilience in rain-based farming systems for
drought stress. These adaptations include: water
harvesting systems, dam building, water conservation
and agricultural practices, drip irrigation, and
development of drought resistant crops.1 These observed
adaptations should be spread across different regions,
nationally coordinated and locally implemented.
Shelter and human settlements
The design of houses and settlements could affect health
through protection against thermal extremes, disasterproofing,
barriers and deterrents to infectious disease
vectors, and energy efficiency.
Development of technological adaptations to cope
with climate change and its health-related problems has
three dimensions: first, technology for new building
structures (eg, energy efficient and built with low-carbon
material); second, planning of settlements, including
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building appropriate infrastructure for flooding control
(eg, Netherlands), having green areas as flood buffers
(eg, Brazil), and designing multiland-use compact cities
to ease transportation (eg, new urbanism initiative in
the USA); and third, acquisition and dissemination of
information, land-use planning, and management
systems for dealing with vulnerability (eg, to natural
disasters), and making city services climate friendly,
such as giving priority to affordable and efficient public
transportation and access to affordable adequate housing
for the population.
Even though technology for settlements to adapt to
climate change has been developed (eg, building standards
to use less energy) and building technologies to adapt to
climate change already exist, the challenge is to make them
available where they are needed by providing knowledge
and financing. Thus, we need to create institutional
mechanisms for making those technologies accessible to
people who will suffer most from climate change and
adjust those existing technologies to the conditions of
developing areas (eg, adapted to environmental conditions,
local affordability, and culture).
Technology does not need to be highly advanced to be
effective. Many basic technologies and planning devices
could be implemented in cities to relieve the strains and
health consequences of urbanisation. Hygienic frameworks
must be put in place: public toilets with adequate
drainage; proper waste disposal; and sanitation policy
enforcement. Local city planning should be done in
collaboration with, and aided financially by, high-level
entities.
Extreme events
Technological challenges to reduce the effects of
extreme events include improvements in regional and
local climate modelling, development of effective early
warning systems, and application of the geographic
information system to improve vulnerability assessment,
hazard and risk zonation, and land-use planning
in an increasingly warm planet. In many developing
countries, cost and expertise shortage limits capacity to
undertake major physical and structural works, such as
improved flood defences, protection of crucial infrastructure,
and modifications to housing construction,
but in many cases low-cost alternative technologies are
applicable.134
Population and migration
Climate change will progressively affect populations in
vulnerable areas, with unpredictable effects on sudden
migration or temporary displacement. Limiting population
growth will help to mitigate climate change and expedite
progress towards poverty alleviation and development.
Huge progress has been made since 1950 in both
contraception and service delivery, but much remains to
be done, especially in Africa. Worldwide, around
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200 million women wish to delay or prevent pregnancy,
but are not using effective contraception. Meeting their
needs would cost about $3·9 billion a year, and could
prevent 23 million unplanned births, 22 million induced
abortions, 142 000 pregnancy-related deaths (including
53 000 from unsafe abortions) and 1·4 million infant
deaths.135 Demand for family planning is expected to
increase in the next 15 years as millions of young people
become sexually active. But funding for family planning
is declining for reasons such as a premature sense that
the overpopulation issue has been solved, criticisms of
inept and sometimes coercive programmes in Asia, and
displacement by HIV/AIDS programmes.136 Family
planning is a low-cost, safe, and acceptable intervention,
with proven benefits that encompass health, education,
and reduction of poverty and environmental degradation.
The sociopolitical challenge
Lifestyle commitments and consumption patterns,
whether in rich or poor countries, need to be understood
in the context of diverse social and political structures
through which individuals and groups assure their
survival and status. Different factors define the matrix
within which human–ecological interactions take
shape. Three key elements of this interaction include:
life–work patterns, time and space relations, and
prestige and value systems. The intersection of these
and other factors gives rise to practices that might
support, or in some cases hinder, the ability of some
groups to respond to climate change. We have
indications, from early phases of environmental stress,
that these different dimensions need to be carefully
disaggregated and that there are complex feedback
systems between them. We urgently need to develop
new models of human socioecological interaction to
address these issues.
Governments should address climate change and its
consequences. The present financial crisis has
emphasised the importance of global governance,
regulation, and government cooperation in providing
security. Baer and Singer115 have analysed the systemic
structures of inequality underlying global warming and
argue that fundamental changes are essential to the
mitigation of several emerging health crises linked to
anthropogenic climate and environmental change.
The move to a low-carbon economy will have global
health benefits from both reduction in the health
effects of climate change and improvement in human
lifestyles, and these must be emphasised through
health promotion. Public health messages in
high-carbon economies should point to the health
benefits of actions to address climate change through
reduced use of cars, less air travel, and lower meat
consumption. Climate has no respect for national
borders or nation-specific government. Global
governance will, therefore, be a central feature of any
discussion of climate change and health. Issues will,
similarly, not be solved by any single discipline. For
example, rising rates of malaria in the Peruvian
Amazon are caused by deforestation increasing the
short-term risk of malaria by creating areas of standing
water in which mosquitoes can lay their eggs.134 Health
here depends on responsible forestry practices. A
structural change, at the political level, is needed to
redistribute resources between rich and poor countries.
Whatever their geographical location, rich individuals
are likely to be better protected than poor people against
negative health effects through their access to mobility,
insurance, and health care. To meet the new targets of
80% reduction in carbon emissions in industrialised
countries by 2050, for example, substantial reduction
in consumption levels and change in the value
associated with some kinds of luxury consumption are
needed (panel 6).
Patterns of disease and mortality
Changing patterns of illness for gradual and extreme
forms of climate change will have sociopolitical
consequences. All epidemiological problems associated
with modernity, mobility, and resource consumption are
exacerbated when climate-related social instabilities are
put in motion. As people migrate away from areas
deteriorated by gradual warming or destroyed by extreme
weather events, they not only place substantial demands
on the ecosystems and social infrastructures into which
they migrate, but also carry illnesses that emerge from
shifts in infectious-disease vectors.
New epidemics are serious issues. Care facilities in
increasingly warm climates, for instance, currently
relegate tropical-disease treatment to specialty (sometimes
exclusive and exclusionary) medical facilities. New
disease vectors, therefore, are not only a problem for
those who suffer, but for professionals educationally or
clinically unprepared to respond to them. Many hospital
facilities in industrialised countries lack experience in
Panel 7: The sustainability agenda and intergenerational
justice
The concept of sustainable development was formulated to
address issues of intergenerational equity in resource
availability. It has been condemned as lacking definition and
conceptual rigour. However, it offers the possibility of
fundamental changes to the way we consume and produce,
the way we arrange our functionally fragmented institutions,
and the way we distribute resources globally and locally. Most
importantly, sustainable development not only posits
environmental degradation and poverty as interconnected
issues, but it gives an example of how mainstream politics
might be brought into a debate that demands a complete
rethink of our institutions, resources, and environmental
outcome, and also assumes that these issues can be solved
with political will.
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managing malaria, and even infections or parasitic
diseases that have emerged in previously cold climates
(eg, dengue fever) are rarely well understood by
practitioners.
Extreme weather events are not always handled well
by rich nations. During hurricane Katrina, for example,
many people were trapped in New Orleans (LA, USA)
because the hurricane occurred at the end of a pay
period when poor people had no money to pay for the
bus fares.138 Increased access to wealth is only an
effective deterrent to disease at income levels that
developed nations have far exceeded and that developing
nations still work to achieve.139 Social stabilities created
by closing the gap between rich and poor in both
developing and developed nations will therefore become
a crucial element in a new capacity building that allows
for better adjustment to the sociocultural consequences
of climate change. Actively building social capital can
be a strong deterrent to migration away from
epidemic-ridden areas, and provides socially stable
populations with infrastructures needed to deal with
unexpected change.
Food
International priorities for food issues related to climate
change include: willingness to ensure fairly distributed
global food security, better use of local resources,
preservation of sustainable ecosystems that provide
local sources of nourishment, and revision of disasterrelief
efforts from emergency food distribution to
long-term capacity rebuilding after climate-related
natural disasters. However, we focus more on immediate
effects of disasters than on improvement of local and
sustainable forms of food production before and after a
disaster. A shift is needed from disaster response to risk
reduction where the capacities of local populations are
strengthened to anticipate and plan for risks ahead of
their occurrence.
Food aid must be coupled with forms of sustainable
reconstruction that are less formulaic and more locally
sensitive. Often, food distribution creates dependencies
without being coupled with locally relevant forms of
reconstruction. Aid organisations that partly or
completely withdraw food aid once a disaster setting has
been identified as in recovery phase must rethink how
the desperation of now-dependent groups is increased
when food aid is withdrawn or fought over in
resettlement camps. Social programmes that educate
consumers about healthy diets and that try to limit the
effects of unhealthy food might have an effect on disease
burdens. Nevertheless, such burdens are mainly carried
by poor people who are likely to face severe constraints
to access high-quality food or to modify their food
choices.
Building local social capital around food supply is a
major challenge. More attention needs to be given to the
global agrifood system, to the added value of industrial
processing, refining, and sweetening, and the economies
of scale created by multinational and transnational
operations. Local food movement might only come when
the crisis has deepened. A generalised reorientation to
locally sourced produce would need both economic
change and political intervention.
Finally, distribution systems that transport food over
long distances not only contribute directly to climate
change but also might decrease immunity when non-local
foods are consumed.140
Water and sanitation
The misuse of water by creating inappropriate climates
to improve specialised forms of agriculture (eg, to water
beef and dairy cattle and other livestock in arid
environments where they are not indigenous and to
service waste disposal systems that use excessive
amounts of water) might undermine efforts to tackle
climate change through positive social action. Farmers
use about three-quarters of the world’s water supply: to
grow 1 kg of wheat requires around 1000 L of water,
whereas 1 kg of beef takes as much as 15 000 L. American
or European diets require around 5000 L of water per
person every day, whereas African or Asian vegetarian
diets use about 2000 L per person every day.141 The social
and political challenge of shifting dietary practices is
enormous, especially as populations start to eat more
meat as they climb out of poverty.
Issues of desertification are well documented and
potentially catastrophic. Tidal surges that salinate and
pollute fresh-water reservoirs and wells cause mass
migrations as changes in monsoon patterns necessitate
the movement of populations out of areas where fresh
water was once available. However, because water is
essential, its misuse has remarkable knock-on effects.
Deforestation and logging create pools of water that,
when exposed to sun, allow mosquitoes and other vectors
to flourish. Vectors might unexpectedly bring new
infections to formerly temperate climates (eg, dengue
fever in North America).
More troubling, however, is the way in which water is
increasingly being used as a cultural weapon. Diverting
water for personal benefit is ancient. But nowadays water
has become a powerful way to oppress vulnerable
populations. Some evidence indicates that the forceful
movement of vulnerable populations against their will
into camps that have limited access to water leads to
oppression of women and abduction of children into
military splinter groups and armies.142 Stress and
post-traumatic stress are increasingly a result of
climate-change-induced conflict.
Shelter and human settlements
The effects of climate change on human settlements can
increase vulnerability to several kinds of health-related
problems. Adaptation of societies to respond to the
causes and consequences of those problems poses huge
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sociopolitical challenges both in developing and
developed countries.
Health vulnerability of urban settlements is not
distributed evenly worldwide.
Some climate-vulnerable countries (eg, small-island
developing states) and poor countries with limited
resources to adapt to climate change tend to suffer most
consequences. Their health systems, already under stress,
have limited ability to respond adequately to
climate-change-related problems. The poorest and weakest
groups, such as elderly people, persons with disabilities,
children, and minorities, would be the most exposed to
climate change consequences. As these groups have
traditionally been more excluded from adequate housing
and from access to adequate health systems, climate
change tends to increase the inequalities in our society.
How to tackle climate-change-related health problems
in urban settlements is a great political challenge
because it involves the creation of an improved
governance system at all levels. First, the most vulnerable
populations need to participate in the decision-making
processes at all levels, from local to global, to ensure
adequate health policies to reduce their vulnerability.
Second, local political will is needed to develop
institutional capacity to create strong public health
systems. Third, coordination at different levels of
governance is necessary to distribute resources and
expertise for adapting to climate change in human
settlements and its health consequences.
As climate change is still a far-away issue in the political
agenda in most local governments, especially in developing
countries, framing climate change as a health issue can
bring political interest in improving public health systems.
The political challenge is to create governance structures
that combine top-down and bottom-up approaches to
change health governance structures towards efficient and
fair processes and outcomes.
Extreme events
The challenge to respond to extreme climatic events not
only for social destabilisation but also in terms of
knowledge can be overwhelming. When governments
attempt to educate populations about the dreadful
consequences of extreme events, they might incite the
panic that their efforts seem to limit. The so-called duck
and cover programmes of the US Atomic Energy
Commission during the Cold War era, which were
designed to educate the public about an unimaginable
catastrophe, have been blamed by social psychologists for
contributing to the presence of panic-related disorders in
children.143 Planning for extreme events has secondary
psychological implications that are rarely addressed by
health practitioners. Indeed, education of the general
public about uncertainty is no simple matter and must
be carried out with responsibility and care, and with
recommendations for alternative forms of adjustment
that are real and feasible.
Social illnesses related to environmental uncertainty
cannot be underestimated because extreme events are by
definition destabilising. Social uncertainty might cause
increased levels of psychological stress because of
instabilities that are both perceived and real.144 Climate
change will, therefore, have an effect on psychosocial
health.97 Increased spending on appropriate counselling
or sympathetic health promotion, and the initiation of
such services in poor countries, could be as important as
planning to reduce new disease vectors.
Population and migration
Although effective measures to achieve demographic
transition through family planning are available and
work, they are not always wanted in either rich or poor
countries. Whether increased consumption is the result
of the rich consuming more or simply more people
consuming, population growth is a factor that needs to
be taken into account in climate change. Paradoxically,
fertility decline has been associated with economic
growth and development. Economic instabilities
associated with climate change might exacerbate, rather
than diminish, population expansion that is not
amenable to education, exhortation, or improved delivery
systems alone.
There is no discussion of models of sustainability
derived from indigenous cultures or from ideologies
not devoted exclusively to the concept of development
as a growth-oriented and progress-oriented ideal.
Although many have benefited from development in
terms of life expectancy, and human development
indices and agricultural productivity have improved
dramatically, these gains are unbalanced across
populations and might be unsustainable. The discussion
of urban population growth worldwide, but
especially in developing countries, makes a strong
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connection between population growth and environmental
change.
Modern spatial epidemiology has mapped migration
caused by extreme climatic events, and the subtle effects,
from desertification in what is now Saharan Africa to
tsunami-related mass migration and resettlement in
south and southeast Asia. Because extreme weather
events do not respect national boundaries, there are
limits to what individual nation states can do to mobilise
disaster responses, and migrants could become
vulnerable to the sentiments of uncertain hosts.
The institutional challenge
The final and overarching challenge is institutional. Our
current institutional arrangements, both private and
public, seem unlikely to be able to guarantee an effective
and equitable policy response to the health consequences
of climate change. Our institutions of government must
reach out to listen and respond to the poorest
communities in ways that have not been previously
achieved. The institutional challenge is one of
coordination with a vertical and a horizontal dimension.
Intervention should occur at different levels of
government, as appropriate to the scale of the issue.
These different levels of government must work
together to support one another and to reinforce the
positive benefits of intervention. Overlapping rather
than exclusive jurisdiction between levels of government
is preferred, with activities at different levels constituting
multiple experiments from which we can learn, and
safety nets to guard against inaction or unsuitable
action at any level. In the USA, for example, individual
states have to take actions to tackle climate change
in the absence of an effective policy response at the
federal level.145
Coordination should form joined-up governments.
Governments are often organised sectorally, segmented
in specialised policy domains. Environment is separate
from health, and health is separate from agriculture.
This is true at all levels of government, including
internationally, where fragmentation and policy contradictions
are a serious problem. WHO deals with health,
whereas the World Trade Organization (WTO) deals
with trade. Each is implicated in the adjustment process
and their actions will need to be coordinated.
Responding to the health effects of climate change
extends beyond the environmental sector, but also
involves the health sector, which needs to have a major
role in the discourse around climate change.
Other institutional challenges relate to power and
politics.146 Global governance is characterised by a lack of
democratic accountability and profound inequalities.
This is most obviously true for organisations such as
private funding bodies, but it is also true of
intergovernmental organisations, including UN bodies
and the World Bank and the International Monetary
Fund. Although these organisations might operate to
increase the accountability of states, to whom the relevant
international organisations are accountable is not always
clear. Also, developing countries are under-represented.20
Difficult choices will have to be made by these institutions
in relation to climate change, and these decisions are
intensely political with important distributive effects.
International organisations are not blind to the need to
respond to perceived accountability deficits. The WTO,
for example, has recently opened its hearings to the
public for the first time. Also, the World Bank established
an inspection panel in 1993 to address the concerns of
people affected by the bank projects and to ensure that
the bank adheres to its operational policies and
procedures during the design, preparation, and
implementation phases of projects. Although these small
steps have many limitations, they are an acknowledgment
that good governance matters internationally and that a
response to accountability problems is possible.
An agenda for developing countries must be put in
place through global cooperation. Representation on
global task forces to assess the health effects of climate
change is heavily skewed in favour of institutions of
developed countries. In poor countries, health assessments
and climate science and health surveillance
research are a priority.
Our ability to develop an effective and fair institutional
framework to respond to climate change will need to
consider market failures and the role of a powerful
transnational corporate sector. Whether in the policy
domain of energy, food, water, or medicines, transnational
corporations are important and mainly unaccountable
entities. We will need to design institutions that are more
responsive to the needs of the poor and less to the
financial demands of big businesses.147 We will also need
to reduce population growth, and help developing nations
to fund services that will ensure that children are born by
choice, not chance.
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Nationally, governments face three main challenges.
First, reduction of carbon-emitting activities needs to
be managed. This is likely to come from strengthened
public awareness of climate change and its potential
effects on health. In the developing world, climate
change issues are perceived by many as distant, diffuse,
and uncertain.148 Developing countries are preoccupied
with the current high burden of disease due to
non-climatic factors and, at the same time, problems
related to health-care delivery in the public systems.
Citizens of the poorest countries should understand
the links between these constraints and climate
change.
Second, locally relevant adaptation technologies that do
not compromise growth need to be identified. Discussion
needs to extend to locally relevant adaptation technologies
that do not harm health.
Third, to support both these goals and to underpin
national adaptation efforts, health effects of climate
change need to be integrated into national plans across
sectors and tiers of government. This action will require
improved understanding of health and climate change at
regional, national, subnational, community, and
individual levels, from the primary sector to public
finance. National plans must financially support key
shifts in policy, facilitate access to better technologies,
and protect health outcomes. Frumkin and colleagues147
have proposed a public health approach to climate change
based on the essential public health services, which
extends to both clinical and population health services,
and emphasises the coordination of government agencies
(federal, state, and local), academia, the private sector,
and NGOs.
There are institutions to undertake these challenges
(eg, in South America and the Caribbean), from capable
national governments to effective regional financial and
research organisations. Such institutions are likely to
gain from cooperation, both from opportunities for
sharing adaptation technologies and from presenting a
unified front when bargaining for increased development
assistance in spite of costly adaptation. Those that do not
have such capabilities must be assisted to face each of
these challenges.
The institutional challenge of adjusting to the adverse
public health effects of climate change is closely tied to
the general challenge of sustainable development, with
its emphasis on equity and environment, and on
wellbeing instead of relentless economic growth.24
Climate change adds new urgency to this challenge, not
least because of the clear disjuncture between cause and
effect; responsibility for climate change is mainly of rich
nations and, although the negative public health effects
of climate change will not be confined to poor nations,
they will be worse there, both in absolute terms and in
terms of relative capacity to cope. Whether viewed as an
ethical imperative or an example of enlightened
self-interest in an interconnected world, a vigorous
anticipatory response to the challenge of adjustment is
urgently needed.
Climate change demands political action and social
mobilisation. However, individuals, organisations, and
governments all have an important role in advocating
and implementing change. Although a complete
response requires a holistic global approach, this should
not be a reason to delay changes that are beneficial to
human health and can be implemented immediately.
Equally, the possibility of partially effective local strategies
should not be seen as a substitute for a full-scale global
response.
Putting climate change at the centre of government
policies enables a number of win-win solutions in
achieving implementation of policies across government
departments. For example, the UK Government energy
policy to cut greenhouse gas emissions by 80% by 2050,
to increase the use of renewable energies, and to ensure
that every home is adequately and affordably heated will
increase the achievement of policy objectives in the
departments of agriculture, transport, and health.
Our findings are in agreement with the main messages
from the international scientific congress on climate
change in Copenhagen in March, 2009. These messages
suggested that, to achieve the societal transformation to
meet the climate change challenge, we need to: reduce
inertia in social and economic systems; build on a
growing public desire for governments to act on climate
change; remove implicit and explicit subsidies; reduce
the influence of vested interests that increase emissions
and reduce resilience; enable shifts from ineffective
governance and weak institutions to innovative leadership
in government, the private sector, and civil society; and
engage society in the transition to norms and practices
that foster sustainability.
Patterns of disease and mortality
WHO has acted to transform some of its organisational
objectives and structures to support ministries of health
in their efforts to develop and implement national policy
on many of the societal factors that affect health, health
equity, and, implicitly, climate change. In May, 2008, the
61st World Health Assembly placed climate change and
health on the global agenda, mandating a more active
WHO engagement in responding to climate change.150
Some national and regional governments have begun
to embrace the health-in-all-policies approach championed
recently by the Finnish Government during its
EU presidency.151 Extending this to include environment
as a core consideration would be a positive
development.
Food
The effect of climate change on food security worldwide
is a public health priority that requires a holistic and
multisectoral policy approach. Tackling both climate
change and food insecurity will not just be a case of
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looking for solutions to provide more food but also will
require policies that can manage ecosystems and
produce food sustainably and effectively, and with the
added goal of improving the lives of poor people. The
Indian Government has recently taken steps to address
a crisis in rural communities, which became manifest
by high rates of farmer suicides, through a programme
of subsidy and increased investment. India, along with
other governments, has considered regulation of
financial systems in which speculation in futures
markets might contribute to food price rises.152,153 Small
changes in food production or crop yields can initiate
big changes in price, especially where unregulated
speculation is possible on commodity exchanges.
Increase in food prices is a major cause of hunger and
malnutrition, which in turn might increase child
mortality rates; therefore, these issues could emerge
over the next 20 years as early indicators of the effects of
climate change on health.
Furthermore, governments need to address patterns
of food consumption. One starting point is to define
and promote a sustainable diet, which could mean
reductions of the incidence of heart disease, cancer,
diabetes, and obesity. R K Pachauri, chair of the IPCC,
recently suggested that a reduction in meat consumption
would be a practical and helpful way for an individual to
contribute to lower greenhouse gas emissions.154 Such
policy would lead to reductions in colorectal cancer and,
probably, ischaemic heart disease.155
According to the South Centre, an assessment should
be done on: the growing use of intellectual property
rights in the agri-food sector and its effect on local
markets and farmers in developing countries; the
displacement of the public sector by the private sector as
the lead investor in agricultural research; and the way in
which profits are disproportionately allocated to the
private sector while negative externalities and risks are
mainly borne by governments and communities.156
Many similarities exist between agricultural research
and development and the challenges experienced by the
health community within the pharmaceutical research
and development sector. At the same time, the agri-food
sector has an important role in ensuring high crop
yields and increased food production to meet the needs
of a global population of more than 9 billion people.
Also, a shift in the way in which humanitarian
emergencies are dealt with needs to be accelerated. The
response still often comes in the form of food aid, which
undermines long-term food security in famine-prone
regions. Instead, in-kind food aid should be replaced,
where possible, with cash donations to agencies that can
purchase food from regional or local markets, making
more efficient use of scarce resources while supporting
local and regional food producers.
The preferences of affluent consumers are shaping
global food and agricultural systems in many developing
countries towards producing export commodities.
Developing countries can use their comparative
advantage in low-labour costs to capitalise on lucrative
American and European markets, while benefiting from
the import of cheap, subsidised grains produced by
agri-business. However, although some countries have
been able to do this (with some even meeting domestic
demand for food despite import surges and growing
participation of transnational companies in the local
market), many countries formerly self-sufficient for
food have become net food importers and susceptible to
the volatility of unregulated and speculative commodity
markets.
A new commitment to rural development is required
to reduce urban drift and rural degradation by both
subsistence communities and industrialisation. Investments
need to be made in rural roads, telephones, and
electricity connections; access to education and health
services is important to allow farmers to produce food
efficiently and effectively; forms of organisation such as
associations, cooperatives, and microcredit groups can
help to reduce costs for agricultural inputs and create
useful economies of scale; and microfinance services
targeted at low-income and poor households need to be
expanded.
Promotion of biodiversity within the agro-ecosystem
is also an important strategy for enabling agriculture to
adapt to the anticipated changing weather patterns and
maximise yield over the medium to long term.157–160 The
2008 world agriculture report highlights a major role for
purposeful biodiversity management in responding to
climate change. A mix of crops and varieties in one field
increases resilience to erratic weather changes, drought,
and flood; reduces the vulnerability to pests and diseases;
and can help to prevent soil erosion and desertification.
Water and sanitation
Integrated water resource systems aim to manage water
for various uses including agriculture, industry,
domestic consumption, and the environment, and have
been implemented in some catchments in Europe,
North America, and Australia. Managing competing
demands for water from various sectors will become
more contentious under conditions of water scarcity
and drought that are likely to increase under climate
change. Reforming existing water management
institutions and creating new authorities will be
important to allow for integrated control of increasingly
scarce water resources, especially in planning for, and
managing, drought, and, where appropriate, in
encouraging transitions to forms of agriculture and
industry with low water requirements.
Water utilities and regulators need to incorporate
climate change predictions and uncertainties when
planning and managing water resources and operations,
including planning for resilience to drought and floods.
Disaster management planning will also be required to
ensure rapid and coordinated responses to floods and
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droughts to avoid outbreaks of disease and maintain
good public health.
Global donors and financial institutions have a key
role in financing the construction and extension of
water and sanitation infrastructure. Funds for water and
sanitation projects should consider equity and
affordability for the system users in ensuring the
long-term viability and appropriateness of infrastructure
systems to provide universal public health benefits
under a changing climate.
Good management of water resources is crucial.
Transboundary management of water resources requires
intergovernmental dialogue, and is important for
regional governance to avoid conflict and allow for
integrated water-resource management. Governmental
authorities need to ensure that utilities, water-resource
managers, and public health authorities are taking into
account climate change in their planning and operations.
Integrated management of water resources might
require national governments to reform existing
institutions to allow for authorities that can implement
decision making together with hydrological rather than
political boundaries. Integrated water resource management
and planning under uncertainty might need local
authorities that share water resources to work closely
together and to participate in regional and catchmentscale
management institutions.
Shelter and human settlements
Only a few countries (such as Netherlands) have
seriously initiated any activities related to adaptation to
climate change. Most countries and subnational
governments might have political, financial, and
operational difficulties establishing effective institutions
to deal with climate change.
The vulnerability of human settlements, especially of
poor people, has not been properly articulated in
adaptation strategies, partly because of the way in which
climate change has been framed, nationally and
internationally, with a bias towards mitigation and with
adaptation analyses limited to rural areas and agricultural
systems. Although efforts put into developing strategies
to assist poor people living in rural areas to adapting to
climate change are crucial and necessary, more effort is
needed to deepen the understanding of equivalent
strategies adopted by poor people in the urban context.
There has been some focus on climate resilience in
urban planning. The UNFCCC local coping strategies
database allows users to search for examples of
successful local coping strategies by type of hazards and
effects, but features almost no information about
documented local strategies within the urban context.100
A need also exists to look at responses not only to
climate-change-related disasters but also to move to
prevention approaches and gradual adaptation to a new
world shaped by climate change, adapting institutions
and promoting innovative organisations. Within human
settlements, planning processes need to adapt to climate
change at all levels (eg, cities, regions, and infrastructures)
to avoid both the short-term inevitable consequences of
climate change during the next 20–30 years due to the
inertia in the climate system and the potential
consequences of non-action or late response. Thus,
information and systems for better planning under
climate change conditions need to be developed, and
land-use planning and building regulations need to be
rethought. Moreover, climate change policies should not
be self-contained but need transversal responses
integrated with other policies (eg, housing, health, and
poverty reduction), and policy responses and efforts
vertically (at the different levels of governance) and
horizontally (within the structure of government, and
with civil society, NGOs, and the private sector).
Adaptation requires local knowledge, skills, and
capacity. Households, community organisations, and
local government need to have the will and capacity to
take action. Simply giving money is not the solution. A
strategy to benefit poor people will not work if local
government refuses to work with them or sees them as
the issue. The vulnerability of both urban and rural poor
people is not simply due to their poverty but, often, to
the failure of local government. Good governance
initiatives are often focused on central rather than local
or municipal governments, and international agencies
fail to understand the limitations and constraints on
local government.
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Private enterprise can potentially unleash significant
investment for adaptation in cities; local government
must encourage local financial services, insurance, and
provision of appropriate supplies to encourage
adaptation, but major infrastructural investment will
remain the duty of the government. The attraction of
local governments into climate change adaptation
investment is complementary to development of goals.
Although much of the policy efforts have been made to
reduce climate change, adaptation in human settlements
has gained momentum in the past few years among
international development organisations. UN HABITAT
has held conferences to discuss global responses to
climate change concerning human settlements. ICLEI
(local governments for sustainability) launched the cities
for climate protection programme involving many cities
worldwide. However, many initiatives lack sufficient
funding for implementation at a large scale and links to
other related international initiatives, such as the
Millennium Development Goals.
Regional initiatives to cope with adaptation to climate
change exist, but few yield results. The European
Commission has organised conferences on the theme
and produced a paper indicating policy options for
adaptation to climate change in Europe in 2007.161 There
are also UN-led initiatives for small-island countries in
the Pacific region and the Caribbean (some of the most
vulnerable regions to climate change), such as the Pacific
Island Adaptation Initiative and the Caribbean
Adaptation to Climate Change and Sea Level Rise, both
started in 2003. In the highly urbanised South America
and rapidly urbanising Asia and Africa, some initiatives
also exist. However, most of these are in the early stages
of execution and might funding for implementation in
the medium and long term.
National governments are still reticent to tackle the
adaptation challenges of human settlements. Netherlands
has done a lot to advance adaptation policies. This country
has high vulnerability to climate change because of its
low altitude, but also has a strong capacity to adapt to
natural adversities. Netherlands has assessed the best
adaptation strategies to cope with the consequences of
climate change, mainly by implementing large
infrastructure projects and making adaptations in
land-use planning. However, island states such as
Vanuatu have started adaptation policies with a priority
on evacuation of the population because they lack the
resources to adapt. Countries have issues engaging in
climate change policies when they conflict with their
national development interests.162
Even though coordination with high-level policies is
lacking, many cities and subnational governments have
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started to include adaptation measures in their planning
processes. One example is the climatic future for Durban
project, which tries to raise people’s awareness about
climate change and integrates adaptation measures into
the development planning process. There are also
initiatives in the civil society. In the Philippines, the Red
Cross has assessed how programmes for communitybased
disaster preparedness can cope with vulnerability
due to climate change.163 However, more initiatives are
needed locally, as many local governance structures
(such as local governments) hold responsibility for
adaptation policies (ie, land-use planning, health, and
transportation), but also link those local initiatives to
national and international efforts to gain scope in
coordination.164
Extreme events
Improved climate modelling will help to constrain future
expectations of extreme meteorological events in terms
of frequency, scale, and temporal and spatial distribution.
Developments in global monitoring, especially satellite
technology and improved communications, can help to
provide short-term alerts of windstorms and floods and
early warnings of droughts and heatwaves, allowing
effective emergency management planning and water
resource and supply arrangements. Improved coordinated
responses by international agencies to extreme droughts
and floods will help to reduce the public health effects of
these events and ensure a rapid return to normality. The
2005 UN world conference on disaster reduction and its
output, the Hyogo Framework for Action (HFA) 2005–15,
articulated for the first time a common international
perspective on interventions and priorities. The HFA
outlines a broad-based vision of disaster risk reduction,
encompassing governance, risk assessment and warning,
knowledge and education, risk management and
vulnerability reduction, and disaster preparedness and
response.165 This vision is perfectly applicable to the
future threats presented by climate-change-related
extreme events, and is now being developed to produce
concrete indicators for disaster risk reduction and
disaster resilience nationally and locally.166,167
With the HFA, disaster risk reduction is becoming
mainstreamed internationally and nationally at policy
level. Also, bilateral donors and international financial
institutions such as the World Bank are beginning to take
disaster risk reduction seriously with respect to their
grant-awarding and lending practices. Growing evidence
exists that national governments are updating pertinent
legislation and disaster management structures.
Although the main aim currently is to improve resilience
of at-risk communities, rather than concerns over coping
with and adapting to climate-change-related extreme
events, the concepts and practice of disaster risk reduction
and climate change adaptation substantially overlap, with
potential for fruitful convergence.168–170 The importance of
governance issues and the idea that the effects of many
natural disasters arising from extreme events are a
function of government policies, structures, and decision
making in development and emergency management
spheres, rather than being technical failures or simple
acts of God, are starting to be recognised.130,171
Much of the burden of managing extreme events falls
on affected communities and local organisations. The
ability to cope with extreme events locally is highly
variable, although often weakly linked to high-level
disaster management systems. Although communitybased
disaster risk reduction is widely promoted and
practised, and highly effective in some instances,
systematic analysis of its effectiveness remains limited.134
Frequently, initiatives are blocked or watered down by a
lack of political will, insufficient funds, or the absence of
expertise or guidance.
Population and migration
For population growth, there are three major
institutional challenges. First, acknowledgment by
governments in developing countries and in the donor
community, by intergovernmental and non-governmental
institutions, civil society groups, philanthropic
foundations, the women’s health movement, and
health-care providers that population growth is
important in climate change and that, addressing it
through global reinvestment in voluntary family
planning services, is both crucial and in agreement
with the requests of developing countries themselves.
Second, all family-planning programmes require
political commitment, clear management and
supervision, sound logistics, and competent staff.
Beyond these basic requirements, it is clear that success
in family planning depends on dismantling the barriers
to contraception. This means considering mobile
services, in addition to static clinics, commercial outlets,
and social marketing schemes to suit local requirements.
Equally important is the removal of conservative
(attitudinal) barriers, combined with education of
lawyers, health-care providers, and religious leaders
about the importance of reproductive health.
Third, policy should be evidence based, and services
should take a life-span approach, aiming to meet the
needs of women throughout their reproductive lives,
through good sex education, contraceptive services, and,
where the law permits, safe abortion services that respect
and protect the rights of people seeking to access those
services.
Asserting that population issues are central to adaptive
responses to climate change is not about blaming the
victim. Lower fertility and smaller families will
accelerate the escape from poverty,172–174 and thus reduce
the background rates of climate-change-related mortality.
Population is the denominator of everything we
do. Increases in population size, whether through
migration or fertility, in regions vulnerable to the effects
of climate change (such as coastal areas) means that
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more people are at risk. Ignoring high rates of population
growth in parts of the world is likely to jeopardise
the success of other responses to climate change and
limit our ability to intervene in ways that respect and
protect human rights.
Conclusions and recommendations
This report raises many challenging and urgent
questions for politicians, civil servants, academics,
health professionals, NGOs, pressure groups, and local
communities. Climate change is potentially the biggest
global health threat in the 21st century. Our response
requires a new public health movement that is
multidisciplinary and multisectoral, and that leads to
coordinated thinking and action across governments,
international agencies, NGOs, and academic institutions.
Any adaptation interventions must sit alongside
the need for primary mitigation: reduction in
greenhouse gas emissions. Indeed, recognition by
governments and electorates that climate change has
enormous health implications should assist the
advocacy and political change to tackle mitigation and
adaptation.
Whichever mitigation strategies are chosen by
governments or agreed at the Copenhagen conference,
the move to a low-carbon economy will have global health
benefits and these must also be emphasised. More
research is needed on win-win solutions, which are equally
important in developed and developing countries.
We have proposed a framework for responding to the
health effects through adaptation strategies, which in
turn embeds mitigation strategies to improve human
health worldwide. This framework raises several important
issues for action:
• Climate change mitigation and adaptation are
essential elements to overall development policy. They
are not separate issues that can be divided from the
agenda for poverty alleviation or for closing the gap on
social inequalities and health.
• The most urgent need is to empower poor countries,
and local government and local communities
everywhere, to understand climate implications and
to take action. Health professionals and university
academics have an important catalytic role. Multidisciplinary
groups from higher education institutions
can have a forceful role in engaging with community
leaders, civil society organisations, and students in
these debates. There is a need for new financing for
global links between developed and developing
countries that create a two-way dialogue. Developed
countries can help to strengthen capacity for
high-quality research and information collection in
developing countries, and developing countries can
strengthen the ability of developed countries to
understand sustainability and low-carbon living.
Empowerment is as much about community
mobilisation as high-level political action. The
empowerment process is likely to be pluralistic and
chaotic, but health and academic communities can
do much to support and catalyse these processes.
• An agenda for developing countries must be developed
through global cooperation. Representation on global
task forces to assess the health effect of climate change
is heavily skewed in favour of institutions in developed
countries. In poor countries, health assessments and
high-level climate science and health surveillance
research are a priority. New research and advocacy
groupings in Africa and south Asia are needed, and
the academic community of developed countries must
have a role in lobbying for resources and support.
Food and water insecurity are early effects of climate
change and will be a high priority for poor
communities. Distilling academic findings into
simple language, policy briefs, and user-friendly
media is essential.
• Climate change should be integrated into the entire
discourse of our present and should be taken into
consideration for all governance actions. An advocacy
movement must ensure that the health effects of
climate change are placed high on the agenda of every
research and development funder, philanthropist,
academic journal, scientific conference, professional
meeting, and university or school curriculum.
Academics should lead advocacy within their own
spheres of influence.
• Accountability mechanisms are crucial. We hope that
this report will initiate or stimulate new funding and
networks to monitor what is happening in
government, civil society, academia, local government,
and communities, especially in the most vulnerable
populations. Accountability indicators should be
monitored by the academic community and civil
society organisations. It should be possible to agree
upon health and climate change goals and targets for
the processes of engagement and empowerment.
Global and regional conferences and working groups
to develop these outputs would be valuable in the
same way that previous reports published in
The Lancet have stimulated action on child survival,
nutrition, and maternal health through the countdown
to 2015. A biennial review of progress towards agreed
targets would help to accelerate progress through
celebration of success and identification of areas
where progress is lagging.
• Awareness of health risks can have an important role
in strengthening carbon mitigation debates and
targets. Joint statements from national institutes of
medicine, representative bodies such as royal colleges,
journal editors, organisations such as the Climate
and Health Council,175 and university leaders
worldwide, drawing upon a growing evidence base,
can create a solidarity and authority that politicians
will find hard to resist. The priority is to send clear
messages to the Copenhagen conference in December,
The Lancet Commissions
www.thelancet.com Vol 373 May 16, 2009 1729
2009, emphasising the health consequences of
climate change, even with a 2°C increase in
temperatures (which is now broadly accepted as
inevitable), with estimates of the severity of health
effects at warming up to 4°C. Public and policy maker
recognition of the profound meaning of the existence
of threats from climate change to nature’s life
processes, to the productive and stabilising ecosystems
upon which we depend, and hence to human health
and survival, will have great effect on the seriousness
and urgency with which we approach this
unprecedented challenge.
• The frequently observed state of fragmented health
systems, with little attention paid to long-term
sustainability, must give way to the development of
coherent, population-based, and bottom-up health
planning. Health systems must not act only as a
platform for the delivery of clinical services but also
provide the foundation for an effective public health
response to the many climate-induced threats to
health. This action will require more attention being
paid to the organisational and management
deficiencies of ministries of health, including
subnational health governance and management
structures. Long-term strategies and investments will
be needed to develop the clinical and management
human capacity of health systems. Some countries
will also need to address the currently unregulated
and disorganised private sector to harness existing
resources to better serve the public interest. Many
countries currently lack any coherent long-term and
sustainable development agenda for their health
systems. This needs to change.
• The move to a low-carbon economy will have global
health benefits from both a reduction in the health
effects of climate change and improvement in
human lifestyles, and these must be emphasised.
There must be more research on win-win solutions,
which are equally important in rich and poor
countries. For example building new green cities in
the developed world, which minimise the need for
cars and maximise exercise, will contribute to the
fight against obesity. In poorer countries, developing
water and energy systems, which are operated by
local renewable sources of power, cuts reliance on
imported fossil fuels and empowers local community
groups.
• Building low-carbon and climate-resilient cities in
emerging economies that adapt to continuing
rural–urban migration, driven both by economic
development and climate effects, is important. More
than a third of the world’s population now live in
urban areas in low-income or middle-income
nations. Even Africa has 40% of its population in
urban areas, a number that is larger than that in
North America. Worldwide, the numbers of people
injured or killed by storms and floods, and the
amount of economic damage caused and insurance
claims made, especially in these urban areas, have
increased.
• Three priorities for action in urban areas are to
improve the capacity and accountability of local and
municipal government, to change their relation to
informal settlers, and to ensure that government
policies encourage rather than hinder the contributions
to adaptation made by individuals,
community organisations, and private enterprise.70
Urban developments could use climate-resilient
engineering on sites at low risk of water or food
stress, and provide sustainable low-carbon transport
and other infrastructure. A new approach to urban
planning to ensure healthy food supplies, adequate
exercise, clean air, clean water, devolved health service
structures, and education might provide a model of
what we mean by a climate-adapted public health
response.
High-income countries have caused almost all the
anthropogenic climate change that has occurred to date,
and they must now face extremely challenging political
and economic choices if climate change mitigation is to
be achieved. The UCL Lancet Commission has recognised
Antonio Gramsci’s pessimism of the intellect and
optimism of the will in tackling this issue. The academic
community has a crucial role in facing up to the challenge
of climate change, the health consequences we shall
bequeath to our children and grandchildren (panel 7),
and in helping to inform and support a policy process
that will challenge us all.
What is a practical way to take the challenge forward?
We call for a collation of global expertise on the health
effects of climate change leading up to a major
conference within the next 2 years, which will define
the priorities for management, implementation, and
monitoring. Representation from developing countries
should be emphasised. The conference should bring
representatives of all interested groups together to
share experiences, and to discuss and endorse a set of
key indicators and targets (climate and health
adaptation goals developed by an international expert
working group) for concerted global action. A key
element of this action programme should focus on
ways in which the poor nations can develop their own
capacity to monitor problems, and to improve the
evidence base for policy makers and planners. We
believe a biennial review of progress towards agreed
targets would help to accelerate progress through
celebration of success and identification of areas in
which progress is lagging.
Contributors
Members of the UCL Lancet Commission contributed to the
development of the structure of the report, writing, and commenting on
drafts. All authors have seen and approved the final version of the report.
Conflicts of interest
We declare that we have no conflicts of interest.
The Lancet Commissions
1730 www.thelancet.com Vol 373 May 16, 2009
Ackowledgments
We thank Malcolm Grant (UCL President and Provost),
Sir Michael Marmot (Epidemiology and Public Health), Ed Byrne
(UCL vice-Provost, Health), David Price (UCL vice-Provost,
Research), Michael Worton (UCL vice-Provost, Academic and
International), Stephen Smith (UCL Economics), and Richard Horton
(The Lancet, London, UK) for their continuing support. We thank
Karen Newman, Louise Carver, and Catherine Budgett-Meakin
(Population and Sustainability Network); Richard Taylor and
Joann McGregor (UCL); Charlie Kronick (Greenpeace); Chris West (UK
Climate Impacts Programme); and Diarmid Campbell-Lendrum (WHO),
for their assistance and advice.
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