Cold snaps and climate change

Top Line

Periodic bouts of extreme cold do not invalidate or weaken the overwhelming scientific evidence that human activities are warming the Earth to dangerous levels. Evidence even suggests that human-induced global warming may be a driving force behind some winter cold snaps, and that Arctic warming in particular may be increa

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• Strong Arctic warming and the associated loss of sea ice combined with La Nina conditions (cool ocean temperatures in the Tropical Pacific Ocean) were found to be factors in the February 2021 extreme cold snap that caused huge societal disruption in Texas and the southern Great Plains.18
• Computer simulations that complement high-resolution meteorological observations predict that as the Arctic continues to warm, we can expect an increase in the frequency and persistence of cold snaps in northern temperate regions including the United States for some years ahead, albeit with weaker intensity.19

Pitfalls to Avoid

• Avoid amplifying the misconception that cold snaps somehow undermine the clear evidence of human-caused global warming—or that any single weather event is representative of what is happening with the climate. In the United States, long-term observations show that high-temperature records are being broken more often than cold records8 and the same is true globally.
• The severity of a cold snap may not be its most disruptive attribute. Even if temperatures are not record-breaking, a long-duration cold spell may have a greater impact than a short, intense one. And when cold penetrates farther southward than normal, communities unfamiliar and unprepared for abnormal cold can be severely disrupted.
• The jet stream exists all year and resides in the atmosphere (about 5-7 miles high, at altitudes where jets fly). It is responsible for creating and steering most of the weather systems experienced in temperate latitudes, including North America and Eurasia. The polar vortex, by contrast, exists only during winter and resides in the stratosphere (about 30 miles over the North Pole); its relationship to weather is less well defined and understood than the jet stream’s. Because the polar vortex typically stays close to the North Pole (and it is the winds associated with the polar vortex that expand southward across the United States), it is best to avoid saying “the polar vortex is coming to X location.”