Downpours, heavy snowfalls, and flooding
A warmer climate will bring an increase in precipitation worldwide, especially during winter and in mid- to high latitudes, according to climate model projections. In addition, more precipitation is expected to fall in downpours and heavy snowstorms leading to increased flooding and damages. The area of the U.S. affected by extreme rainfall has increased significantly since 1910. Heavy rainfalls have also increased in Japan, the former Soviet Union, China, and Australia. As climate change increases the risk of flooding, human changes in land use and land cover can also contribute to the growing risk of flooding.
Hotspot Selection Criteria: Observed events in this category are consistent with the projections for a more intense hydrologic cycle as outlined by the IPCC (2001), including more winter precipitation at mid to high latitudes and a greater portion of precipitation from heavy downpours. They are considered examples of events that would become more frequent and/or more widespread with continued global warming. For the rainfall events we confirmed that the region has been experiencing either an increase in heavy precipitation or an increase in annual precipitation, using journal articles or Annex A of the IPCC Regional Impacts report (IPCC, 1998). For flooding, we did not include events for which other factors (e.g., land clearing or wetland filling) were clearly major contributors, such as the summer 1998 flooding in the Yangtze Valley in China.
Harbingers of Global Warming
Things are proceeding as predicted.