Lancet and University College London Institute for
Global Health Commission
Managing the health effects of
climate change
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 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 nshe 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.
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 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.
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 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 on public health of billions of people.
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.
Global warming also threatens global biodiversity. Ecosystems are already being hugely degraded by habitat loss, pollution, and hunting. The millennium ecosystem assessment. suggested that three known species are becoming extinct every hour, whereas the 2008 living planet report. 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, 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.
