Climate Change 2001:
Working Group II: Impacts, Adaptation and Vulnerability
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9.15. Conclusion

The prospect of global climate change affecting patterns of human health poses a central challenge to scientists and policymakers. For scientists, the causation of most of the health outcomes considered in this chapter—from respiratory and cardiovascular disease to various types of infectious diseases—is complex: Various social, technological, demographic, behavioral, and environmental factors influence the risk of occurrence of these diseases. For that reason, it will remain difficult in the near future to identify any early impacts of the current climate trends on health. This complex causation of human disease also means that predictive modeling of future climatic impacts should take realistic account of the coexistent and modulating effects of nonclimate factors.

Over the past 5 years, we have acquired better understanding of direct temperature effects on health (heat and cold), temperature effects on air pollutant production, the seasonality of certain infectious diseases, and the public health consequences (and situational modifiers) of extreme weather events. Predictive modeling of how scenarios of future climate change would affect the patterns and impacts of vector-borne diseases has evolved, as has modeling of impacts on regional agricultural yields and the geography of world hunger.

Policymakers should appreciate that although our scientific capacity to foresee and model these various health outcomes of climate change continues to evolve, it is not possible to make precise and localized projections for many health outcomes—especially those that result indirectly from a sequence of impacts. In the meantime, a precautionary approach requires that policy development proceed on the basis of the available—though often limited and qualitative—evidence of how climate change will affect patterns of human population health. Furthermore, high priority should be assigned to improving the public health infrastructure and developing and implementing effective adaptation measures.



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