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The Impacts of Global Warming on the United States

Global warming is a term that refers to changes in climate due to human industrial processes. These processes include emissions from industry, farming and vehicles, which release gases such as carbon dioxide, methane and fluorinated chemicals that trap solar radiation and heat up the planet. In the United States, the Environmental Protection Agency (EPA), and the U.S. Global Change Research Program (USGCRP) are institutions that perform and collate research into this weather phenomenon. According to both of these organizations, global warming already has had a variety of effects on the country.

  1. Temperature Rises

    • The USGCRP states that the average temperature in the United States rose by over 2 degrees Fahrenheit since the 1960s. This is in line with the global trend for a rise in temperature. This data indicates that Alaskan winters will be warmer than before, and the rest of the country will be warmer in summer than before. The USGCRP also projects a further temperature increase of up to 11 degrees Fahrenheit by the end of the 21st century, if gas emissions are not controlled.

      Snow and ice coverage in the country is also reduced, according to the EPA. For example, glaciers in Alaska melt quicker than before, and lake ice all over the country now is not as extensive as it was in the first half of the previous century.

    Increase in Rain

    • According to the EPA, higher temperatures increase the rate of evaporation of water from the ground, which then turns into rainfall. The USGCRP interpretation of the data agrees with this concept, and the organization states that 5 percent more rain fell in 2009 than at the beginning of the 1960s. However, this is an average across the country, with rain increasing and decreasing in different areas. For example, California and Nevada have more rain in the winter but less in the summer, and the Southeast and Northwest have less rain than before. The Midwest experiences more heavy rainfall than before. The USGCRP also projects that heavy downpours will occur more often than they did before global warming.

    Extreme Weather Events

    • Hurricanes from the Atlantic Ocean are more intense than before global warming, according to the USGCRP, due to the warmer ocean temperatures. Pacific-origin hurricanes occur less often but are also more intense. The incidence and strength of tornadoes do not appear to have been affected by global warming.

      The country has experienced more localized droughts than previously, and higher temperatures, according to the EPA and the USGCRP, can make droughts more intense. Heat waves are more frequent than before and also more intense. Both organizations predict that the frequency of heat waves will increase.

      The sea level has risen up to 8 inches in areas such as the Gulf of Mexico and part of the Atlantic coast since the 1960s, and in some areas, the sea level has fallen.

    Ecosystem Changes

    • The variation in weather that the EPA and the USGCRP attribute to global warming has significant effects on the ecosystem and people of the United States. For example, the intensity of Hurricane Katrina, which may have been increased by global warming, destroyed a city and severely damaged 320 million trees, according to the USGCRP.

      Crops are attuned to temperature and weather conditions. According to the EPA, the average growing season in the lower 48 states is two weeks longer than it was a century ago. This may be beneficial for farmers in these states, but changes in weather can also restrict the types of crops suitable for the areas.

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