Health, disease and climate change

Posted: 30 March 2009

Climate change - whether natural or man-induced - will inevitably have an impact on the distribution patterns of diseases, especially those which are transmitted by insects and other fauna whose range is determined by climatic factors such as temperature and seasonal changes.

  • According to the WHO, the health effects of a rapidly changing climate are likely to be overwhelmingly negative, particularly in the poorest communities which have the least ability to cope with climate change impacts and have also contributed least to the problem.

  • Some of the health effects include:

    • Increasing frequencies of heat waves: recent analyses show that human-induced climate change significantly increased the likelihood of the heat waves like the European summer heat wave of 2003.
    • More variable precipitation patterns will compromise the supply of freshwater, increasing risks of water-related diseases.
    • Rising temperatures and variable precipitation are likely to decrease the production of staple foods in many of the poorest regions, increasing risks of malnutrition.
    • Changes in climate are likely to lengthen the transmission seasons of important insect-borne diseases such as malaria, dengue fever and yellow fever, and rodent-borne diseases like typhus and plague, and to alter their geographic range, potentially bringing them to regions which lack either population immunity or a strong public health infrastructure.
    • Malaria, a disease transmitted by the Anopheles mosquito, is restricted to humid regions with average temperatures above 16°C (61°F), covering around 45 per cent of the world. Global warming will inevitably expand the mosquito's range, putting millions more people at risk of the disease.

    ratRats and rodents thrive in degraded environments© Mark Edwards/Still Pictures

  • Malaria, a disease transmitted by the Anopheles mosquito, is restricted to humid regions with average temperatures above 16°C (61°F), covering around 45 per cent of the world at present. Global warming will inevitably expand the mosquito's range, putting millions more people at risk of the disease.

  • An increase in extreme weather events - such as floods and droughts - will have serious repercussions for human health. For example, floods will help to spread water-borne diseases. Conversely, droughts might help diseases like West Nile virus. (see Section on Health and Pollution)

  • A WHO assessment concluded that the effects of the climate change that has occurred since the mid-1970s may have caused over 150,000 deaths in 2000. It also concluded that these impacts are likely to increase in the future.

  • According to a report by the Pew Center on Global Climate Change, global warming could exacerbate health risks for the elderly, the sick and the poor. If climate change results in more heat waves, and worse air pollution, then these groups are most at risk.

Climate change and disease in Colombia
Climate change and disease in Colombia
Click to enlarge image. Source: UNEP/GRID-Arendal

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