Northeastern University

We were cold: Climate change and the polar vortex

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Photo via Thinkstock.

Photo via Thinkstock.

Search the words “polar vortex disproves climate change” and you’ll get a whole lot of articles saying the exact opposite: “The polar vortex in no way disproves climate change,” (Washington Post); “No, the Polar Vortex Does Not Disprove Global Warming,” (Slate); “Polar Vortex and Climate Change: Why cold weather doesn’t disprove global warming,” (International Business Times).

So what I’m about to tell you should not come as a shock: The polar vortex does not disprove climate change. Indeed, no single cold snap, no matter how freaking freezing it may be out there, says all that much about global warming…or even global “weirding,” as some like to call it.

In 2011, Northeastern associate professor Auroop Ganguly and his lab published a paper in the journal Geophysical Research Letters, which was one of the first to show that extreme cold weather events–like the one we just survived–will continue late into the 21st even under the worst global warming conditions. As a research highlight in the journal Nature pointed out, their work suggested that such cold spells could even be more intense and more prolonged in the future.

“Natural processes, for example the North Atlantic Oscillation and La Niña, may continue to play a strong role in cold weather events,” said graduate student Evan Kodra, who led the 2011 study. “They can temporarily mask the longer term warming that is expected to accompany rising greenhouse gases.”

Kodra and the other members of Ganguly’s team haven’t looked specifically at the polar vortex–which is a naturally occurring wind pattern constantly in action around the poles–but it’s another example of one of these natural processes that he’s talking about.

As post-doctoral researcher Rachindra Mawalagedara explained it to me, the polar vortex usually takes on a roughly circular pattern in the upper atmosphere above the poles. But various things can cause the shape of the vortex to become distorted, sending southward-reaching tentacles of frigid arctic air into the normally more temperate regions.

“Some literature suggests that atmospheric warming is amplified near the poles, which leads to polar ice melt,” said Kodra. Since water absorbs more heat than ice does, this could be responsible for a temporary distortion of the vortex. “But it would be preliminary at best to make a claim that this one event we’re experiencing is actually caused by global warming,” he continued.

Mawalagedara explained that it’s the long term patterns–not individual incidents or even short term patterns–that matter when it comes to evaluating climate change. “With our current state of understanding, it’s hard to attribute a single event to climate change,” she said.

So, the last few days of unbearably cold weather were not proof of climate change nor were they proof of its nonexistence. We were cold and science suggests we’ll continue to be cold well into the future.


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