Global Warming Raises Outbreaks of Disease

Paul R. Epstein, M.D., M.P.H. is Associate Director of the Center for Health and the Global Environment at Harvard Medical School and is a medical doctor trained in tropical public health. Paul has worked in medical, teaching and research capacities in Africa, Asia and Latin America and in 1993, coordinated an eight-part series on Health and Climate Change for the British medical journal, Lancet. He has worked with the Intergovernmental Panel on Climate Change (IPCC), the National Academy of Sciences (NAS), the National Oceanic and Atmospheric Administration (NOAA) and the National Aeronautics and Space Administration (NASA) to assess the health impacts of climate change and develop health applications of climate forecasting and remote sensing.

Dr. Epstein also served as a reviewer for the Health chapter of the Millennium Ecosystem Assessment and coordinated Climate Change Futures: Health, Ecological and Economic Dimensions, an international project with Swiss Re and the United Nations Development Programme assessing the new risks and opportunities presented by a changing climate.

He is currently coordinating a Cat Modeling Forum with A.I.G., Lloyd's of London and other insurers and insurance brokers, facilitating integration of dynamic and statistical models for better risk assessment and reduction. Dr. Epstein is also preparing a report that examines the "stabilization wedges" through the lens of health and ecological safety. Paul received recognition for his contributions to the work of the Intergovernmental Panel on Climate Change, awarded the Nobel Peace Prize in 2007. In addition, Dr. Epstein has recently published Healthy Solutions for the Low Carbon Economy: Guidelines for Investors, Insurers and Policy Makers (July '08).

Paul Epstein--

Climate change has direct, indirect and broad-scale consequences for human health and well-being. Heat waves affect health directly and are projected to take an increasing toll in developed and developing nations. Climate affects the range of infectious diseases, while extreme weather events are affecting the timing and intensity of outbreaks. Warming and more weather extremes also encourage pests and pathogens afflicting forests, crops, livestock, wildlife and marine life (especially coral reefs).

Several issues underlie the observed climate- and weather-related changes in disease distribution: 1. Since 1950, nighttime and winter warming have occurred twice as fast as has overall global warming; 2. The pace of warming in temperate, boreal and polar latitudes is occurring faster than warming in the tropics; and 3. Since 1957, the first International Geophysical Year, when many global measurements were initiated, the world ocean has accumulated 22 times the amount of heat as has the atmosphere, accelerating the global hydrological cycle.

Extremes are particularly conducive to upsurges of pest populations, e.g., mosquitoes and rodents. Drought in East Africa, in association with a warming Indian Ocean, led to the explosive outbreak of Chikungunya fever (similar to dengue fever and also carried by Aedes aegypti mosquitoes) in 2004-06, which has since spread to Italy. Sahel drought is related to upsurges of meningococcal meningitis and, in Latin America, heavy rains and flooding have been associated with outbreaks of dengue fever. Sequences of extremes create conditions conducive to “clusters” of mosquito-, rodent- and water-borne disease outbreaks.

Excess carbon dioxide itself (CO₂) has consequences for human health. Ragweed grown under elevated CO₂ levels produces pollen disproportionately to increases in its stem growth, and the pollen proteins become more allergenic. Additionally pollen grains are food for the larvae of anopheline mosquitoes, thus CO₂ fertilization may contribute to increasing malaria.

The longest term threat climate change poses for public health comes from the direct impacts on ecological systems – forests and coastal marine -- that provide us with air, water and nourishment, thus constitute our life-support systems.

On the other hand, clean energy solutions can improve health directly and provide the basis for clean water, agriculture and nutrition, education, health care and small-scale development – that form the basis for health in developing tropical nations. Clean energy solutions can also stimulate businesses and create jobs. Finally, all proposed technologies must also be examined with regard to their health, safety and environmental impacts. Life cycle analyses can help separate those technologies that are “no-regrets” – and can be scaled up today – from those – like nuclear and biofuels -- requiring further study to avoid unintended health and environmental consequences.

With the proper financial incentives and the dismantling of “perverse incentives,” the clean energy and technology transition can improve public health, help stabilize the climate and become the engine for the global economy in this 21^st Century.