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Alicia Wang / Sun Sketch Editor

February 1, 2019

What’s Causing the Cold? The Science Behind the Polar Vortex

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The past two days proved dismal for Cornell students and faculty, who battled freezing temperatures and wind chills of 29 degrees below zero across campus. As a mind-numbing polar vortex descends on Ithaca, many Cornellians may wonder: What could possibly be creating such heinous weather?

Prof. Art DeGaetano, earth and atmospheric sciences, shared what’s really going on with The Sun, citing climate change, the jet stream and warming Arctic regions.

“The short answer is the jet stream,” DeGaetano said. “The jet stream is an area of strong winds high in the atmosphere. It mainly moves west to east, but tends to be quite wavy, undulating north and south. When the jet stream undulates south, it allows cold Arctic air to cover the United States.”

While the jet stream phenomena has existed for millennia, recent changes in climate have affected its wavelike patterns, exacerbating the cold spells that frequent the mid and upper United States.

“Under climate change, Arctic regions have warmed substantially more than areas farther south.  This reduces the contrast in temperature, and as a result, the jet stream tends to be more wavy.  This allows cold Arctic air to affect New York more frequently,” DeGaetano explained.

While students may consider this Arctic weather an anomaly, DeGaetano noted that days when the temperature remains below minus five degrees have been common since 1893 — when observations first started to be recorded in Ithaca.

“Days as cold as this have occurred quite regularly every three or four years. There were three days like this last year and also in 2015,”  DeGaetano said.

Despite cold winters being a regular phenomenon, DeGaetano explained that climate change dramatizes temperature flux across the globe.

According to DeGaetano, as climate change is exacerbated, we can expect more variable conditions ranging from heat waves to cold snaps in the short term. However, as time goes on, “we will see conditions continue to warm and cold spells like this become less likely,” he said.

Yet the science behind this week’s Polar Vortex seems to be poorly understood by politicians, DeGaetano said.

Though some — such as President Donald J. Trump in a recent tweet — have used the Arctic temperatures to share skepticism about “global warming,” DeGaetano argues that climate change, the more scientifically accurate term for global warming, contributes largely to this crazy cold.

DeGaetano further explained that cold weather has nothing to do with what skeptics call the absence of climate change, and political statements in the past few years regarding below-freezing temperatures have only infuriated scientists.

“I am yelling. This flawed line of reasoning confuses weather and climate,” DeGaetano said. “A cold day or even week or month is weather. Climate describes longer term changes and changes over broad areas.” DeGaetano emphasized that the eastern U.S. is a small part of the entire Earth, which is even now seeing warmer than normal temperatures.

Despite politics, do not let the discomfort you feel while walking to class encourage climate change skepticism. Because before you know it, winds in the jet stream will be sending heat up the hill and the harsh reality of climate change will again seem realistic. Until then, stay warm.