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Climate Change


Climate is the average weather in a region over time. Climate change refers to major, long-term changes in temperature, rainfall, snow, or wind patterns. Natural factors or human activities may cause climate change. Today climate change is happening at an increasingly fast rate.

Human activities may contribute to global warming, a factor in climate change. Global warming is caused by releasing high levels of heat-trapping pollutants, called greenhouse gases, into the atmosphere.

Greenhouse gases

Carbon dioxide emissions make up about 80 percent of all greenhouse gas emissions in the United States. Other greenhouse gases include methane, nitrous oxide, volatile organic compounds, ozone, and chlorofluorocarbons. Burning fossil fuels such as oil, coal, propane, diesel fuel, natural gas, and gasoline produces greenhouse gases. Electricity generation, industrial processes, agriculture, and forestry may also release greenhouse gases.

Climate effects on health

Climate change can cause changes in rainfall; reduced snow and ice cover; extreme weather events such as floods, wildfires, blizzards, and hurricanes; sea level rise; and increased temperatures, which in turn may cause heat waves and drought. These changes can affect our health. They can lead to:

  • More heat-related illness and deaths. 
  • More pollen, mold, and air pollution, which can cause an increase in allergies, asthma, and breathing problems. 
  • Increased ozone and smog, also aggravating respiratory conditions.
  • More mosquitoes and other insects that carry diseases.
  • More floods and rising sea levels, which can cause an increase in contaminated food and water.
  • More extreme weather events, which can cause death, injuries, stress, and mental health problems.

Some regions around the world are at particular risk for climate effects on health, including:

  • Regions with high rates of climate-sensitive diseases like malaria
  • Coastal areas at risk of flooding
  • Areas with little capacity to adapt due to social and economic factors

Slowing and adapting to climate change

Choices you make in day-to-day life can help slow climate change. Here are a few ways you can help:

  • Be energy efficient
  • Drive and fly less
  • Eat less meat and dairy, eat local foods
  • Use renewable power, such as wind and solar 
  • Recycle
  • Plant trees

Some changes due to climate change cannot be avoided. Adaptation helps communities deal with those consequences. Communities may adapt by planting more drought-resistant crops or protecting coastal areas from rising sea level with infrastructure.

National Library of Medicine Resources and Databases
  • Climate Change
  • Curated links to current consumer health information on the effect of climate change on human health. These English and Spanish web resources include background information, clinical trials, and journal articles.

Additional Resources
  • Climate and Human Health (National Institute of Environmental Health Sciences)

    A 2010 report addressing the health impacts of climate change, including major research areas to be explored, such as respiratory allergies and airway diseases, cancer, cardiovascular disease, food and waterborne illnesses, and neurological and weather-related diseases, from a federal institute that investigates the interplay between environmental exposures, human biology, genetics, and common diseases to help prevent disease and improve human health.

  • How Climate Change Impacts Health (American Public Health Association)

    Information on how climate change impacts human health, and advocacy efforts to advance health equity.

  • Climate Change and Health (World Health Organization)

    A factsheet on how climate change's impacts, which include extreme heat, natural disasters, and variable rainfall patterns, adversely affect health, as well as information on populations at risk for these effects, and the response from the World Health Organization.

  • Climate Effects on Health (Centers for Disease Control and Prevention)

    Information on how climate change impacts human health from the Third National Climate Assessment's Health Chapter, including factsheets on how changes in weather, including extreme heat, extreme rainfall and drought, and air pollution, contribute to illness and injury.

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