Last updated January 28, 2020

Total Precipitation Increase

While heavy precipitation events in most parts of the United States have increased in both intensity and frequency, there are important regional and seasonal differences in total precipitation change. Climate change is linked to increased total precipitation and flood risk in the US Midwest.

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Climate science at a glance

  • The 12 months spanning July 2018 through June 2019 were the wettest year-long period in the United States in records dating back to 1895.

  • Climate change has increased the likelihood of wet years across the US.[1][2]

  • In the Midwest, significant increases in flooding are well-documented, and the change is likely due to increases in total precipitation linked to climate change.

US total precipitation trends and climate change

  • In the Northeast, increases in total precipitation are expected during the winter and spring but with little change in the summer.[3]
  • In the Southern Great Plains, total precipitation decreased over the past 30 years.[3] An increase in extreme precipitation, however, has led to an increase in record-breaking flooding over this same period of time.[3]

US studies attribute changes in total precipitation to climate change

  • (Knutson and Zeng 2018): Climate change has increased the amount of annual precipitation in the Midwest.
  • (Diffenbaugh et al. 2017): Climate change has increased the likelihood of wet years over the US.
  • (Knutson et al. 2014): Extreme seasonal and annual mean precipitation during 2013 in the north-central and eastern US were due in part to human-caused climate change.

Global total precipitation trends and climate change

  • Climate models robustly predict an increase in global-mean precipitation in response to CO2 doubling. They agree that the magnitude of this increase will be less than the increase of water vapor concentrations.[4]

Global studies attribute changes in total precipitation to climate change

  • (Wan et al. 2014): Increases in high latitude precipitation has showed an increase in various datasets, and this is due in part to human caused climate change.
  • (Sarojini et al. 2012): Human-caused climate change has likely increased total precipitation across the globe, with the largest effect in high-latitude regions.
  • (Zhang et al. 2007): Models detect the effect of anthropogenic climate change on average precipitation across latitudinal bands.