Climate Change and Rainfall
This information supplements the "Climate Change and Rainfall" section of the Rain Garden Manual for Vermont and the Lake Champlain basin. It will help you prepare for the rain storms of the future and size your rain garden accordingly.
Rainfall extremes intensify as the climate warms. Oceans encompass almost 70% of the Earth’s surface, and as global temperatures increase, more water will evaporate into the atmosphere from oceans, lakes, and soils. Every increase of 1°F temperature enables the atmosphere to hold 4% more water vapor. This increase in water vapor held by the air is predicted to result in more frequent and heavier downpours, which can amplify the risk and severity of flooding. Data compiled by the National Atmospheric and Atmospheric Administration (NOAA) show:
- Temperatures in Vermont have increased more than 2°F since the beginning of the 20th century.
- Average annual precipitation is projected to increase in Vermont over the 21st century, particularly during winter and spring. Corresponding increases in temperature will increase the proportion of precipitation falling as rain rather than snow.
- Extreme precipitation events are projected to increase, potentially increasing the frequency and intensity of floods.
Source: NOAA State Climate Summaries (data through July 2020)
- Learn about climate change in Vermont on this webpage by the Vermont Department of Health
- Check out these articles by Leonard Perry, UVM Extension on impacts from climate change including coping with increased precipitation and with colder temperatures
- Use the Vermont Climate Change Mapping Tool in visualizing some of the projected precipitation changes in Vermont. Go to Climate Data --> Precipitation. Explore historical (1980-2014) changes in precipitation, projected days of heavy precipitation, and projected annual precipitation by county in Vermont.
- Two other interactive tools are the Vermont Climate Data Grapher and the Climate Explorer