How is climate change affecting geyser activity? Climate Basics Read more from Chapter Climate Change

Geyser activity is affected by rainfall levels and the frequency of earthquakes. In Yellowstone National Park, which is home to about half of the world’s 1,000 known geysers, rainfall feeds into the Madison River, which supplies geysers in the park with their water reserves. Less rainfall in times of drought translates into less pressure in the geysers’ reservoirs, and leads to fewer eruptions. In a recent study of rainfall and climate in Yellowstone, it was found that the amount of water flowing down the Madison River has decreased by about 15 percent from the years 1998 through 2006.

This decrease in rainfall has been blamed on global warming, which has affected precipitation in the surrounding states of Wyoming, Montana, and Idaho. The study associated lower rainfalls with an increase in the intervals between eruptions of geysers. For example, Old Faithful used to erupt every 75 minutes, and in 2006 it was erupting every 91 minutes.