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3 Things People Get Wrong About The Polar Vortex And Climate Change

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I was interviewed by several media outlets this week about the extreme cold that plunged into the United States. The events, particularly in Texas, were tragic and deserved the coverage. As a weather - climate expert often called upon by the media, I could not help but notice three things that continue to surface in these dialogues. I suspect they may reveal themselves within broader public discourse as well.

The first one relates to the Polar Vortex itself. It is very common to get comments like “The Polar Vortex caused this cold outbreak?” or “The Polar Vortex came into the United States this week.” The Polar Vortex is not a storm that comes to get us like the boogeyman or a tornado. An “oldie but goodie” blog post by Brian McNoldy, a weather expert at the University of Miami, is a solid reference on this point. McNoldy wrote, “The polar vortex (also sometimes called the circumpolar vortex) is a large, persistent, upper-atmospheric, cyclonic circulation that forms and exists over the winter pole.” Many people might be surprised to learn that other planets have them too. McNoldy continues, “It is not a winter storm, or a storm of any kind. It's just a natural part of Earth's circulation 10 to 30 miles up in the atmosphere.”

If the Polar Vortex is disrupted or weakened, then Arctic air can spill into the lower 48 states in one of the U-shaped features (trough) below. NOAA scientist Michelle L’Heureux explained it brilliantly in the New York Times by using the analogy of the Polar Vortex as a chain-linked fence holding in a group of animals. If there is a breach in the fence, a few animals might escape, but if the entire fence collapses, they all come piling out.

Which leads me to the second thing that I kept hearing this week. Did climate change cause this outbreak? I co-authored a 2016 National Academy of Science report on extreme weather attribution to climate change. In that report, we concluded that contemporary extreme events likely have climate change “DNA” in them. A previous Forbes piece touched on the findings and nuances of that report. However, one of the most important recommendations from the expert panel was that media and decision-makers must stop asking if that event was caused by climate change. To me, it is like asking if the 358th home run hit by a Major League Baseball player using steroids was caused by the performance-enhancing drug. That player could likely hit a home run naturally without steroids. However, it is likely that a detectable influence of the steroids can be seen in his overall home run statistics (number and length). In the report, we recommended questions like:

  • Are events of this severity of becoming more or less likely because of climate change?
  • To what extent was the event more or less intense because of climate change?

The report also found that strongest statements about climate change attribution can be made about extreme temperature events, intense rainfall, and drought. As for the Polar Vortex, there are studies which suggest that climate change might lead to more disruptions or “fence weakening” in the future. According to an outstanding primer on this topic on the University of California-Davis website, “While the polar vortex is well documented, its behavior has become more extreme as a result of climate change, according to (Paul) Ullrich.” As the Arctic region warms disproportionately compared to the tropics, there is also evidence that the Jet Stream becomes “wavier” such that its lobes penetrate more southward. For more on this topic, consult the explainer recently written by Seth Borenstein of the Associated Press.

It is important to step back and remember that it is February and winter in the Northern Hemisphere. Cold snaps happen. However, experts are concerned that these breaches are happening more frequently. Borenstein’s cites research published in a leading meteorology journal that finds that such events are happening yearly rather than every other year or so.

The final thing that I notice is something very counterintuitive to many people. You can have extreme cold in one part of the world and warm anomalies (difference from normal) elsewhere. The map below shows temperature anomalies as of February 21, 2021. The colder air in the middle of the United States is evident. However, warm anomalies are noticeable in extreme polar regions as well as parts of Asia. As a climate scientist and communicator, it is a constant struggle to shake people out their narrow perspective that what happens in their little corner of the world is indeed local not global.

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