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Country experiences of assessing health implications of climate change

For over 20 years, WHO has provided technical information on the links between climate change and health.  For over 10 years, the Organization has worked directly with countries to raise awareness of these links, and their implications for health policy, and is now coordinating health vulnerability and adaptation assessments in over 20 countries.  At the end of July, 16 countries covering all regions of the world were brought together for the first time, to share their experience of evaluating health risks in different parts of the world, in a meeting organized by the Pan-American Health Organization/WHO, and hosted by the Government of Costa Rica.

The meeting was centred on draft guidance for health vulnerability and adaptation assessment, produced by PAHO, building on earlier work  by the WHO European Regional Office.  Representatives from each country presented on their experience in carrying out national assessments and in using the draft guidance, and made proposals for improving the final version.

A series of common themes emerged from the discussions.

1) Health leadership is critical.  It is sometimes assumed, even by the health sector itself, that climate change is an environment or development issue, and several countries shared their experience of initial hesitancy for health actors to engage in this area.   However, most also shared positive experiences: in Costa Rica for example, high-level engagement of the Ministry of Health helped to ensure that the assessment considered not only vulnerabilities and adaptations within the formal health sector, but in other “health-determining” sectors, such as water and agriculture.

2) Climate change does not affect health in isolation.  All of the participants come from countries that suffer a range of stresses on health and health systems.  They were therefore clear on the need to ensure that  efforts to address climate change are integrated with programmes underlying health issues, such as building on existing programmes to protect health from extreme weather events, control vector borne diseases, and provide drinking water.  None, however, argued that the existence of other problems was a reason to postpone action on climate change.

3) This is not a one-off intervention, but a long-term process.  Health has a long and successful tradition vertical interventions to deal with specific diseases.  Climate change presents a very different challenge, requiring the assessment of wide-ranging, complex and uncertain risks, and gradually strengthen and adapt health systems (in the widest sense) to manage them better.

Overall, the feedback on the guidance was positive, and a new version incorporating comments and examples from the countries will be published late in 2010 .   Probably the most encouraging result of the meeting, however, was the emergence of a “community of practice”, of health professionals from around the world, who are working to assess and respond to the health risks of climate change.

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Health poorly covered in National Adaptation Programmes of Action for climate change

Impacts on human health and wellbeing are one of the three sets of “adverse effects” that the UN Framework Convention on Climate Change is designed to prevent.  The international public health community has also now recognized climate change as a high priority, most obviously through a 2008 World Health Assembly Resolution,  which particularly notes the need for interventions to protect health in developing countries.

In order for this to occur, health needs to be represented in the planning and funding processes of the climate community (and vice versa).  The secretariat of the UNFCCC therefore asked the WHO Regional Office for Africa, and WHO Headquarters, to review health coverage within the National Adaptation Programmes for Action.  These have been developed by the Least Developed Countries (LDCs), to plan their most urgent and immediate needs for adaptation measures, and to justify international funding support.

The results of the review do not make encouraging reading.  As the summary states:

It was found that 39 of 41 NAPAs reviewed (95%) consider health as being one of the sectors on which climate change is seen as having an impact. However, only 23% (9/39) of these plans were found to be comprehensive in their health-vulnerability assessment.

In total, 73% (30/41) of the NAPAs include health interventions within adaptation needs and proposed actions, but only 27% (8/30) of these interventions are found to be adequate. The total number of selected priority projects is 459 but only 50 (11%) represent projects focused on health. The total estimated cost of the priority projects is USD 1,852,726,528 with just USD 57,777,770 (3%) going to health projects.  It is concluded that with few exceptions, the current consideration of public health interventions in NAPAs is unlikely to support the resilience processes and protect public health from the negative effects of climate change.”

This should not really be a surprise, particularly as the health sector has only recently begun to engage seriously on this issue,  for example through actively participating in national climate change processes.  Instead it is encouraging that the UNFCCC asked for this review, and is interested to hear from the health sector on how to address the problem.  WHO will be working with national partners, and with the UNFCCC , to raise the coverage and quality of health input into future climate change planning, and to support concrete interventions to protect health and wellbeing.

The full text of the review ” Overview of health considerations within National Adaptation Programmes of Action for climate change in least developed countries and small island states” by Lucien Manga, Magaran Bagayoko, Tim Meredith and Maria Neira,  can be found on the WHO website.

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New study on malaria and climate change

Last week, Nature published an important new study by Peter Gething and colleagues from Oxford University, examining changes in the global distribution of malaria over the past century1.   The findings suggest that during the past 100 years, the protective effects of socioeconomic development and disease control have been significantly greater than the transmission-enhancing effects of increasing temperatures.  The study therefore builds on and supports previous qualitative reviews, as well as analyses of the effect of climate and other factors on long term trends in malaria transmission over smaller areas2.

The study does not directly exonerate climate from a role in malaria transmission, either in the past or in the future.  Indeed, the results of other studies by the same group suggest that, compared to a situation where climate remained stable, human-induced climate change will tend to increase malaria risks for a large number of people in the least-protected regions3.  It does, however, provide important context, by indicating that future development and disease control programmes, if maintained and expanded from their present scope, could have considerably larger protective effects.

The paper relates the findings to previous modelling studies of the effects of climate change on the present burden and future risks of malaria, and their use in assessments by WHO and other agencies.  The WHO assessment does attribute a small proportion of the current malaria burden to the more favourable climate conditions associated with global warming.  In doing so, however, it takes into account that this existing burden has already been strongly affected by non-climatic factors – so the results are not necessarily in contradiction.

Initial reactions by other scientists also suggest that this will not be the final word on the analysis itself.  In the past, some of the study’s authors have criticized other researchers for relying on simple models of malaria which do not account for the complexities of local disease transmission. Yet here they use models of the global retreat of malaria (mainly reductions in Plasmodium vivax at high latitudes) to draw conclusions about current and future malaria burdens – which are overwhelmingly a function of the very different transmission dynamics of Plasmodium falciparum in Africa.  Scientists may also question why the study looked only at the effects of future temperature increases, since changes in rainfall may be more important4.

The most important question, however, is not whether the research is perfect, but what it means for policy and practice.  The authors main conclusion is that concern over climate change should not divert malaria control programmes from their current efforts to control the disease.  While there is no evidence that this distraction is occurring, it does strengthen the case made by WHO and others, that increased risks from climate change should be addressed through existing control programmes rather than as a stand-alone activity, and need to be supported by additional resources, rather than existing health budgets.

As is often the case in studies relating to climate change, subsequent coverage is likely to both amplify and distort the research findings.  While the authors aim to focus attention back on to the basics of malaria control, it is telling that this study has been heavily covered, while their more applied work in mapping current malaria distributions goes effectively unreported.  Some are also apparently using this work as part of a general opposition to climate science and policy, for example claiming that models based on climate change, and previous IPCC reports, have led to disease control efforts being diverted away from malaria in Africa. For its part, WHO argues that the wide range of health risks posed by climate change call for more, rather than less, investment in the kind of preventive disease control measures highlighted in this study.


1. Gething PW, Smith DL, Patil AP, Tatem AJ, Snow RW, Hay SI. Climate change and the global malaria recession. Nature;465(7296):342-5.

2. Kuhn KG, Campbell-Lendrum DH, Armstrong B, Davies CR. Malaria in Britain: past, present, and future. Proc Natl Acad Sci U S A 2003;100(17):9997-10001.

3. Hay SI, Tatem AJ, Guerra CA, Snow RW. Foresight on population at malaria risk in Africa: 2005, 2015 and 2030. Scenario review paper prepared for the Detection and Identification of Infectious Diseases Project (DIID), Foresight Project, Office of Science and Innovation. London, UK, 2006: 40.

4. Small J, Goetz SJ, Hay SI. Climatic suitability for malaria transmission in Africa, 1911-1995. Proc Natl Acad Sci U S A 2003;100(26):15341-5.

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What does “Climategate” mean for health?

The unauthorized release of climate researchers emails, and both accepted and alleged errors in the IPCC reports, have led to widespread negative reporting of climate science, just as the public health community has begun to engage with the issue. So, are we wasting our time in looking at climate change?

At the most basic level, the answer is clearly no. The conclusion that climate change is happening, and is due mainly to human activities, is based on well-established physics, supported by a large body of observations, and endorsed by almost all experts publishing on the issue. This is equivalent to the expert consensus that HIV causes AIDS, or that smoking is an important risk factor for lung cancer. Extraordinary evidence would now be needed to overturn any of these positions.

Nonetheless, the new criticisms may well affect public opinion – which in several countries is now very much at odds with the expert assessment.  While many commentators attribute this to the actions of the scientists concerned, the nature of modern communication of scientific issues is also likely to be at least as important.  This includes the media practice of providing balance only by giving equal coverage to extreme opposing positions, the actions of large commercial and ideological lobbies that seek to amplify evidence and viewpoints that support their own vested interests and attack those that do not, and a strong tendency for people to ignore information that suggests that they should make unwelcome behavioural changes.

While the media debate continues, the real question for the public health community is not “is climate science perfect?”, but “are we proposing the most responsible actions, in the light of the best available evidence?”

The balance of evidence indicates that climate change will mainly have negative effects, but the uncertainty is large in both directions, ranging from the potential for some positive effects in some populations, to diverse, widespread and severe impacts on health and health equity.  Fortunately, there is much more certainty about the best responses.  Actions such as controlling vector-borne diseases and providing clean water and sanitation, would both save lives now, and increase resilience to gradual climate change.

The same approach applies to cutting greenhouse gas emissions to reduce climate change.  Many of the necessary actions bring cost savings, while many others would bring enough public health benefit (for example through reduced air pollution) to repay the cost of investment. Policies such as cleaner and more equitable energy provision and more sustainable transport systems, are therefore good both for public health and for the environment.

Although we are confident in the measures that we are promoting, we need to remain absolutely open to any serious new findings that have a direct bearing on policy. The recent furore does not seem to have brought forward any such evidence. We continue to work with countries that have a  range of health stresses and are now at increasing risk of being flooded by rising sea-levels and more severe weather, or suffering prolonged drought, or are struggling to provide clean energy to increasing populations. Unfortunately, nothing in the recent coverage suggests that we will be able to give up this work anytime soon.

A longer version of this article, with supporting references, was published as “Science, media and public perception: implications for climate and health policies” in the Bulletin of the World Health Organization.

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Taking the heat out of the population and climate debate

Climate change and population, taken individually, are among the most contentious issues in public policy; bringing the two issues together is a recipe for controversy.  The issues are linked, however, so we do need to find a constructive approach to talk about the connections.

For all of its complexities, the basic challenge of climate-change policy is the apparent conflict between maximizing short-term individual or national gains (increasing per capita GDP through use of cheap fossil fuel energy) and the long-term protection of shared benefits (minimizing global damages from climate change).  The other dimension is fairness, as those populations that have contributed least to past emissions of greenhouse gases are most vulnerable to health and other impacts of climate change. Developing countries are therefore reluctant to limit their greenhouse gas emissions to help solve a problem that has, so far, been created elsewhere. For their part, richer countries hesitate to implement policies that they consider may harm their economic growth and competitiveness.

In some ways this is analogous to discussion of population policy. Again, there is a potential tension between the immediate rights of individuals (to control their own fertility) and a longer-term, population-level concern (that rapid population growth could potentially overstretch resources, hamper development and lay conditions for conflict).

These two issues are also closely linked. Although the major driver of greenhouse gas emissions remains the consumption patterns of richer populations, human population is also a fundamental long-term driver. However, discussing these links has often generated more heat than light.  Even stating the fairly obvious fact that having more children will tend to increase an individual’s “legacy” of greenhouse gas emissions has sparked outraged reactions against perceived threats to individual freedom or faith.  These tensions also play out at national level, as some have suggested that curbing population growth in developing counties would help to reduce climate change. In response, developing countries point out that per capita emissions of children born in poor countries are much lower than that in richer countries, and claim that they are being stigmatized for “profligate reproductive behaviour” as a negotiating position over greenhouse gas commitments.

Can these issues be discussed constructively? The best approach is probably to choose the least controversial entry point – identifying where human rights, health, environmental and equity objectives converge, rather than conflict. This can be framed around the fact that, in developing countries, approximately 200 million women express an unmet need for family planning services. Meeting this need is supported by the following arguments.

First, control over reproduction is an individual right, supported through international declarations, and embodied in the Millennium Development Goals. Second, it provides major public health benefits; increasing birth spacing from less than 18 to more than 36 months correlates with a two-thirds drop in childhood mortality. Third, avoiding local overpopulation increases resilience to near-term environmental and other stresses (a need identified by most of the poorest countries themselves). Fourth, over the long-term, it relieves climate change and other pressures on the global environment.

When developing this case, the order of the arguments is critically important. Individual rights come first, with the population health, local and global environmental benefits as welcome and important co-benefits. In contrast, using the need to reduce climate change as a justification for curbing the fertility of individual women at best provokes controversy and, at worst, provides a mandate to suppress individual freedoms.

Although the case for family planning services should be self-evident, it needs to be carefully constructed, and sensitively handled.

(A longer version of this article, with supporting references, was published in the Bulletin of the World Health Organization:

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Climate change mitigation should bring large, direct health benefits

In May, the front cover of The Lancet stated that “Climate change is the biggest global health threat of the 21st Century“.

The current front cover makes more encouraging reading.  “This series makes clear that health co-benefits can accrue as a direct result of many mitigation activities for greenhouse-gas emissions.  If societies change their energy systems, change their methods of transport, and modify intensive food production practices and consumer choices, then many positive health consequences will result“.

This special issue includes a series of studies by a group of leading public health researchers, on the likely health implications of policies in a range of sectors, that would be necessary to reach ambitious greenhouse gas mitigation targets.  They conclude that more sustainable and lower-carbon choices in all of these sectors would bring substantial benefits to public health.  In India, for example, a proposed programme to introduce 150 million low-emission cooking stoves would reduce both the warming effect of black carbon, and indoor air pollution.  It would therefore be expected to gain approximately 12 500 years of healthy life per million population by the year 2020 – roughly equivalent to eliminating half of the total cancer burden in the country.  In the United Kingdom, for example, introduction of selected policies aimed at reducing transport emissions by 60% by the year 2030, would be expected to bring major health gains: 10–20% reductions in heart disease and stroke, 12–13% in breast cancer; 8% in dementia, and 5% in depression.

These health gains are more local and immediate than the long-term and globally distributed benefits of reduced damage to the global climate, and should therefore be of direct interest to policy makers and the general public.  The study also shows that putting an economic value on the health benefits, even in the sector that gives the lowest health returns (electricity generation), would be large enough to cover the cost of mitigation in some large rapidly developing countries.  This supports the conclusion of the last IPCC report, that  the costs of many mitigation interventions would be partly or wholly compensated for by health benefits.  This strongly indicates that these health benefits should be included in any cost-benefit analysis of new technologies or policies relating to energy use.

This is, of course, far from the end of the story.  Although the analysis is the best possible given current data, the authors document a series of research questions that should improve future estimates.  More fundamentally, while the work describes the very large pay-offs from greener practices, it does not directly address what policy measures could bring about these changes.  Promoting new technologies, or getting people to change their behaviour is never going to be easy.  Barriers include the large vested interest in current ways of doing things, and the fact that the potentially large health benefits are largely “off the balance sheet” for the relevant sectoral decisions.

These new studies show, however, that doing things differently would be very good for health, as well as for the environment.

An Executive Summary, the full papers, and accompanying editorials, are available for download from The Lancet.

Disclaimer: The views expressed in these posts are those of the staff members working most closely on the relevant issues, but are not necessarily formal positions of WHO.

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