Scientists are increasingly able to link rising global temperatures to heat waves, droughts, flash floods and hurricanes.
But figuring out how a warmer world will affect tornadoes is trickier. The United States is uniquely suited to tornadoes, and experiences more than any other country each year – an average of 800. Most of them occur in the middle of the country over the Great Plains, a region known as „Tornado Alley.“ Tornadoes are produced by storms when key ingredients come together: warm, moist air near the ground, cool, dry air above the ground, and changes in wind speed and/or direction, known as wind shear. Harold Brooks, chief scientist at the National Oceanic and Atmospheric Administration’s National Severe Storms Laboratory in Norman, Oklahoma, said it was not entirely clear how climate change was affecting these different conditions. „It doesn’t mean there isn’t a connection, it just means it’s a lot harder to pin down than it might be for some other things,“ he told The Independent. For example, rapidly warming polar regions are reducing average wind shear, which reduces one of the conditions needed for tornadoes to form. „Some things are favorable, some things are not,“ Mr. Brooks said. Still, there are some „relatively reliable“ observations of tornadoes that may be related to climate change, he added. Over the past 50 years, the number of days per year with tornadoes has decreased, but the number of days with multiple or „clusters“ of tornadoes has increased.

Louise Boyle, The Independent