In the United States, Europe and China, global warming has also meant more heavy rain. As the planet warms, more water evaporates into the air and then falls as precipitation. Climatologists forecast more intense downpours, falling more frequently, in the coming decades.
For the United States, the amount of rain falling during the most intense downpours has increased by 20 percent nationally during the past 20 years, according to the National Climate Assessment.
Rainfall intensity increased the most in the Northeast and Midwest. By 2070, regions of the United States could experience an extra two days per years with rainfall exceeding the historical heaviest drenchings (see map below).
Climatologists forecast that Europe will experience more frequent intense downpours as well. In northern Europe, disastrously intense rainfall events may strike every six to 10 years, compared to the current 20 years, according to a forecast published in Tellus, a meteorology journal. Scandanavia’s winters may drop extreme amounts of precipitation every two to four years.
Southern China, particularly in the east, now receives more rain than in the past, according to a review published in Nature. Rainfall has also increased in China’s northeast.
Although rain reduces the need for agricultural irrigation, intense downpours can drown crops or pummel seedlings. Coasts face a double threat of inundation from heavier rains along with rising sea levels.
The effects of climate change can’t be clearly seen yet in claims to insurance companies, according to a study in the Bulletin of the American Meteorological Society. The greatest risk from natural disasters may result from people moving into exposed areas, such as floodplains and coasts, putting more homes and lives at risk.
Photo: An aerial shows flooding in New Orleans as a result of Hurricane Katrina. Credit: Jocelyn Augustino, FEMA, Wikimedia Commons