IPCC Fourth Assessment Report: Climate Change 2007

8.8 Key uncertainties and research priorities

More empirical epidemiological research on the observed health effects of climate change have been published since the TAR, and the few national health impact assessments that have been conducted have provided valuable information on population vulnerability. However, the lack of appropriate longitudinal health data makes attribution of adverse health outcomes to observed climate trends difficult. Further, most studies have focused on middle- and high-income countries. Gaps in information persist on trends in climate, health and environment in low-income countries, where data are limited and other health priorities take precedence for research and policy development. Climate-change-related health impact assessments in low- and middle-income countries will be instrumental in guiding adaptation projects and investments.

Advances have been made in the development of climate–health impact models that project the health effects of climate change under a range of climate and socio-economic scenarios. The models are still limited to a few infectious diseases, thermal extremes and air pollution. Considerable uncertainties surround the projections, including uncertainty about how population health is likely to evolve based on changes in the level of commitment to preventing avoidable ill-health, technological developments, economic growth and other factors; the rate and intensity of future climate change; uncertainty about how the climate–health relationship might change over time; and uncertainty about the extent, rate, limiting forces and major drivers of adaptation (McMichael et al., 2004). Uncertainties include not just whether the key health outcomes described in this chapter will improve, but how fast, where, when, at what cost, and whether all population groups will be able to share in these developments. Significant advances will occur by improving social and economic development, governance and resources. It is apparent that these problems will only be solved over time-frames longer than decades.

Considerable uncertainty will remain about projected climate change at geographical and temporal scales of relevance to decision-makers, increasing the importance of risk management approaches to climate risks. However, no matter what the degree of preparedness is, projections suggest that some future extreme events will be catastrophic because of the unexpected intensity of the event and the underlying vulnerability of the affected population. The European heatwave in 2003 and Hurricane Katrina are examples. The consequences of particularly severe extreme events will be greater in low-income countries. A better understanding is needed of the factors that convey vulnerability and, more importantly, the changes that need to be made in health care, emergency services, land use, urban design and settlement patterns to protect populations against heatwaves, floods, and storms.

Key research priorities include addressing the major challenges for research on climate change and health in the following ways.

  • Development of methods to quantify the current impacts of climate and weather on a range of health outcomes, particularly in low- and middle-income countries.
  • Development of health-impacts models for projecting climate-change-related impacts under different climate and socio-economic scenarios.
  • Investigations on the costs of the projected health impacts of climate change; effectiveness of adaptation; and the limiting forces, major drivers and costs of adaptation.

Low-income countries face additional challenges, including limited capacity to identify key issues, collect and analyse data, and design, implement and monitor adaptation options. There is a need to strengthen institutions and mechanisms that can more systematically promote interactions among researchers, policy-makers and other stakeholders to facilitate the appropriate incorporation of research findings into policy decisions in order to protect population health no matter what the climate brings (Haines et al., 2004).