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The window for meaningful climate action is closing.
Link to tweet
Climate change is also making heat waves longer
There’s another way that climate change worsens heat waves: by changing the jet stream. Those air currents in the atmosphere help move weather systems around and are driven by temperature differences, which are shrinking. So when heat waves arrive, they stay in place longer.
“We’re warming up the Arctic faster than the rest of the northern hemisphere,” said Dr. Mann. “So that’s decreasing that temperature contrast from the subtropics to the pole, and it’s that temperature contrast that drives the jet stream in the first place.”
At the same time, under certain circumstances the jet stream can get “stuck” between an atmospheric wall in the subtropics, and at the Arctic, trapping weather systems in place.
“That’s when you get these record breaking weather events," said Dr. Mann, “either the unprecedented heat wave and drought, to wildfires and floods.”
This accounts for last summer’s European heat wave, as well as the recent European heat wave, he says, and is behind the current North American heat wave.
Nationwide, the time period in which heat waves might be expected to occur is 45 days longer than it was in the 1960s, according to the U.S. Global Change Research Program.
There’s another way that climate change worsens heat waves: by changing the jet stream. Those air currents in the atmosphere help move weather systems around and are driven by temperature differences, which are shrinking. So when heat waves arrive, they stay in place longer.
“We’re warming up the Arctic faster than the rest of the northern hemisphere,” said Dr. Mann. “So that’s decreasing that temperature contrast from the subtropics to the pole, and it’s that temperature contrast that drives the jet stream in the first place.”
At the same time, under certain circumstances the jet stream can get “stuck” between an atmospheric wall in the subtropics, and at the Arctic, trapping weather systems in place.
“That’s when you get these record breaking weather events," said Dr. Mann, “either the unprecedented heat wave and drought, to wildfires and floods.”
This accounts for last summer’s European heat wave, as well as the recent European heat wave, he says, and is behind the current North American heat wave.
Nationwide, the time period in which heat waves might be expected to occur is 45 days longer than it was in the 1960s, according to the U.S. Global Change Research Program.
1 replies
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