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The topic, like the planet, is vast. Overwhelming. Complex. But there’s no more important time to understand what is happening and what can be done about it.
Why are extreme cold weather events happening if the planet is warming?
The connection between climate change and extreme cold weather involves the polar jet stream in the Northern Hemisphere, strong winds that blow around the globe from west to east at an altitude of 5 to 9 miles. The jet stream naturally shifts north and south, and when it shifts south, it brings frigid Arctic air with it.
A separate wind system, called the polar vortex, forms a ring around the North Pole. When the vortex is temporarily disrupted — sometimes stretched or elongated, and other times broken into pieces — the jet stream tends to take one of those southward shifts. And research “suggests these disruptions to the vortex are happening more often in connection with a rapidly warming, melting Arctic, which we know is a clear symptom of climate change,” said Jennifer A. Francis, a senior scientist at the Woodwell Climate Research Center.
In other words, as climate change makes the Arctic warmer, the polar vortex is being more frequently disrupted in ways that allow Arctic air to escape south. And while temperatures are increasing on average, Arctic air is still frigid much of the time. Certainly frigid enough to cause extreme cold snaps in places like, say, Texas that are not accustomed to or prepared for them.
Where the extreme cold occurs depends on the nature of the disruption to the polar vortex. One type of disruption brings Arctic air into Europe and Asia. Another type brings Arctic air into the United States, and “that’s the type of polar vortex disruption that’s increasing the fastest,” said Judah L. Cohen, the director of seasonal forecasting at Atmospheric and Environmental Research, a private organization that works with government agencies.
It is important to note that these atmospheric patterns are extremely complicated, and while studies have shown a clear correlation between the climate-change-fueled warming of the Arctic and these extreme cold events, there is some disagreement among scientists about whether the warming of the Arctic is directly causing the extreme cold events. Research on that question is ongoing.