I was interviewed by several media this week about the extreme cold that plunged in the United States. The events, particularly in Texas, were tragic and deserved coverage. As a meteorologist who is often called upon by the media, I couldn’t help but notice three things that continue to crop up in these dialogues. I suspect they may also reveal themselves in a wider public discourse.
the First refers to the polar vortex itself. It is very common to get comments like “The polar vortex caused this cold outbreak?” or “The Polar Vortex arrived in the United States this week.” The Polar Vortex is not a storm that comes to us like a boogeyman or a tornado. An “oldie but goodie” blog post by Brian McNoldy, a meteorologist at the University of Miami, is a solid reference on this point. McNoldy wrote: “The polar vortex (also sometimes referred to as the circumpolar vortex) is a large, persistent upper atmosphere cyclonic circulation that forms and exists above the winter pole. Many people might be surprised to learn that other planets have them too. McNoldy continues, “This is not a winter storm, nor a storm of any kind. It is just a natural part of the earth’s circulation 10 to 30 miles in the atmosphere. “
If the polar vortex is disturbed or weakened, arctic air can spread to the lower 48 states in any of the U-shaped (hollow) features below. NOAA scientist Michelle L’Heureux explained it brilliantly in the New York Times using the polar vortex analogy as a chain fence holding a group of animals. If there is a breach in the fence, a few animals might escape, but if the whole fence collapses, they all pile up.
Which brings me to second thing that I continued to hear this week. Did climate change cause this epidemic? I co-wrote a National Academy of Science Report 2016 on attributing extreme weather conditions to climate change. In this report, we concluded that contemporary extreme events likely have climate change ‘DNA’ in them. A previous Forbes room discussed the conclusions and nuances of this report. However, one of the panel’s most important recommendations was that the media and policymakers should stop questioning whether this event was caused by climate change. To me, it’s like asking if the 358th home run hit by a Major League Baseball player using steroids was caused by the performance enhancing drug. This player could probably hit a home run naturally without steroids. However, it is likely that a detectable influence of steroids can be seen in his overall home run statistics (number and length). In the report, we recommended questions such as:
- Are events of this severity more or less likely due to climate change?
- To what extent has the event been more or less intense because of climate change?
The report also found that the strongest claims on attributing climate change can be made regarding extreme temperature events, intense rainfall and drought. Regarding the polar vortex, some studies suggest that climate change could cause more disturbance or “weakened fences” in the future. According to an outstanding introduction to this topic on the University of California-Davis website, “While the polar vortex is well documented, its behavior has become more extreme due to 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” so that its lobes penetrate more towards the south. For more on this topic, see the explanation recently written by Seth Borenstein from Associated press.
It is important to take a step back and remember that it is February and winter in the northern hemisphere. Cold snaps occur. However, experts fear that these violations will occur more frequently. Borenstein quotes research published in a leading meteorological journal which finds that such events occur every year rather than every two years or so.
the last thing that I notice is something very counterintuitive for a lot of people. You may have extreme cold in one part of the world and hot anomalies (difference from normal) elsewhere. The map below shows the 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 the extreme polar regions as well as parts of Asia. As a climatologist and communicator, it’s a constant struggle to get people out of their narrow perspective that what is happening in their little corner of the world is indeed local and not global.