USA: East Coast tornadoes may be a sign of things to come, researchers say
By Kendra Pierre-Louis
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Though it’s not possible to quantify to what degree, if any, climate change played a role in the tornadoes in New York and Massachusetts, researchers have some inkling into how climate change will affect tornadoes more broadly.
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Researchers know that there are two ingredients that fuel severe storms that could spawn tornadoes: potential energy in the air and wind currents, or wind shear. The rising levels of greenhouse gases in the air add more energy to the climate system, Dr. Diffenbaugh said. There’s less consensus on how climate change will affect wind shear, though a 2013 study on the thunderstorm conditions that form tornadoes found that the impact was negligible.
Over all, “We do have strong evidence that at the large scale that global warming is likely to increase the atmospheric environments that create the kind of severe thunderstorm that produces tornadoes,” Dr. Diffenbaugh said.
When scientists run climate models assuming global average temperatures of one degree Celsius (two degrees Fahrenheit) higher thanpreindustrial levels — where the Earth currently stands — some show an uptick in tornado frequency, but others do not. That disagreement, however, fades away at two degrees Celsius of warming, the threshold that the Paris climate agreement is intended to avoid. All the models agree that the frequency of tornadoes will increase by that point.
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