Guest essay by Eric Worrall
Although global warming might have been implicated in harsh weather in the Rockies, Forbes author Dr. Marshall Shepard definitely wants to make it very clear he is not trying to link this snow event to climate change, even though there is a growing body of evidence that global warming will make extreme cold and snow more likely.
The Blizzard In The Rockies Doesn’t Disprove Climate Change But People Will Say It Anyhow
Marshall Shepherd Senior Contributor
Sep 29, 2019, 04:52pmI predicted several days ago that some people would be tweeting that this early season snowstorm in parts of the Rocky Mountain region somehow refutes anthropogenic climate change. Rob Bailey, a computer engineer in Ohio, brought the Tweet at this link to my attention. I am sure there are many more just like it.
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So why is the region experiencing such record cold and snow conditions in terms of magnitude of the event? To answer this question, we have to look to the jet stream. According to the NWS Glossary, the jet stream is a region of “relatively strong winds concentrated in a narrow stream in the atmosphere, normally referring to horizontal, high-altitude winds….The position and orientation of jet streams vary from day to day.” The wavy pattern of the jet stream is a very strong determinant of general weather patterns, particularly in terms of temperature and wetness. With this storm, the jet stream plunged southward bringing extremely cold air into the region. An upper-level low approaching from the Pacific region supplied the moisture.
To be clear, this is a weather event. I am not attributing it to climate change at all. However, I do want to conclude with something that is very counterintuitive to many people. There is a growing body of evidence (and a few counter-narratives) in the peer review literature that suggests that because the Arctic region is warming, there is less of a difference in temperature between the polar and tropic regions. That difference, called a gradient, is what determines the strength of the jet stream. If the difference is smaller due to so-called Arctic Amplification (warming in the Arctic), the jet stream would be wavier. The “so what” is that a jet stream with greater wave amplitude means more extreme troughs or “dips” with cold air and more extreme ridges or “humps” with warm air. In other words, the extremes on both sides of the temperature range are amplified.
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The following image seems to have upset Dr. Shepherd, because some cruel contrarians are using this image to mock the urgency of our global warming emergency.
Now don’t any of you go upsetting Dr. Shepherd even further by suggesting what he wrote doesn’t make sense.
