“Was this caused by climate change?”
Meteorologist Dan Satterfield, with WBOC TV in Salisbury, Maryland, opens this month’s “This is Not Cool” video with the question he often is asked after extreme flooding, rains, fires, and drought such as occurred this summer.
“Kevin Trenberth, at [the National Center for Atmospheric Research] is right,” says Satterfield. “Climate has a handle on all of our weather now.”
According to Trenberth, “The environment in which all events occur these days is different, so in fact every storm is different, every event is actually different. It has to be. The air, being warmer, means it can also hold more moisture. There’s more moisture in the air, especially coming off of the oceans.”
“Intense rainfall events are increasing in many parts of the world, including most of the United States,” says Texas State Climatologist John Nielsen-Gammon of Texas A&M.
“It’s affecting our heavy precipitation events,” adds Katharine Hayhoe of Texas Tech.
The video offers examples of heavy rains and record snowfalls reported in recent years across Louisiana, the U.S. East Coast, and in the British Isles.
On a warmer planet, Hayhoe explains, evaporation happens faster. “So when that storm comes along, as it always does, there’s more water vapor sitting up there for that storm to pick up and dump on us.” Hayhoe points out that warmer ocean temperatures mean that when hurricanes occur, they can draw on more fuel in the form of warm air and moisture.
MIT hurricane expert Kerry Emanuel notes, “There is evidence that indeed, the frequency of the high-end events is going up.”
With more localized storms, such as tornadoes, thunderstorms, and hailstorms, the record is not yet long enough to make definitive statements. “We don’t have standard measurements of tornado strength going back,” Nielsen-Gammon says.
Meteorologist Scott Mandia makes a comparison to a basketball game with the court floor raised by a foot. The same players can more easily dunk the ball. “Now, storms that technically are not major hurricanes are causing major hurricane damage,” Mandia says.
Noting the degree of damage from this summer’s torrential Louisiana rains, Bill “the Science Guy” Nye points out that the storm was not a powerful hurricane, but in effect just “a day at the office in Louisiana.”