How will global warming harm human health and well-being?

October 29, 2020

The major public health organizations of the world have said that climate change is a critical public health problem. According to the U.S. National Institute of Environmental Health Sciences, climate change makes many existing diseases and conditions worse, and it helps pests and pathogens spread into new regions. The most vulnerable people—children, the elderly, the poor, and those with health conditions—are at increased risk for climate-related health effects.

Edward Butcher, 64, looks out into the street as he sits near the window to stay cool in his non-air conditioned apartment on a sweltering Wednesday, Aug. 2, 2006 in the Ridgewood section of the Queens borough of New York. AP Photo/Jason DeCrow.

Examples of public health risks

  • Extreme heat and poor air quality increase complications from underlying heart and respiratory conditions like asthma, renal failure, and pre-term birth, and as temperatures rise, there will be more heat-related illness and deaths in both urban and rural areas. 
  • Americans will be exposed to more frequent and/or intense extreme weather and climate events that not only threaten their lives and health, but also significantly disrupt health and social services. 
    • The risk of very large fires has increased and will increase further across California and other parts of the West, directly threatening people’s lives and causing severe air pollution across large areas.
    • The frequency and intensity of heavy downpours has increased and is likely to increase further, raising the risk of flash flooding.
  • Ticks and mosquitos that transmit illnesses like Lyme disease and West Nile virus are likely to increase and spread to new areas in the United States. 
  • More frequent heavy rain events will likely increase Americans’ exposure to water-borne illnesses, including those linked to sewage contamination of drinking water. Recreational waters are likely to experience more outbreaks of aquatic pathogens, including Vibrio bacteria and harmful algal blooms.
  • Human-caused climate change also threatens food safety in multiple ways including lowering the nutritional quality of staples like wheat and rice, causing greater accumulation of mercury and other toxins in seafood, and increasing the chance for food-borne pathogens to enter to food supply.

More U.S. impacts. More global impacts.


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Ebi, K.L., J.M. Balbus, G. Luber, A. Bole, A. Crimmins, G. Glass, S. Saha, M.M. Shimamoto, J. Trtanj, and J.L. White-Newsome, 2018: Human Health. In Impacts, Risks, and Adaptation in the United States: Fourth National Climate Assessment, Volume II [Reidmiller, D.R., C.W. Avery, D.R. Easterling, K.E. Kunkel, K.L.M. Lewis, T.K. Maycock, and B.C. Stewart (eds.)]. U.S. Global Change Research Program, Washington, DC, USA, pp. 539–571. doi: 10.7930/NCA4.2018.CH14

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