Does the Polar Vortex Contradict Global Warming?
Record-breaking cold temperatures courtesy of the polar vortex have taken over the Midwest, leaving many people wondering what has become of global warming. President Trump echoed these sentiments in a tweet on January 28: “In the beautiful Midwest, windchill temperatures are reaching minus 60 degrees, the coldest ever recorded. In coming days, expected to get even colder. People can’t last outside even for minutes. What the hell is going on with Global Warming? Please come back fast, we need you!”
At face value, the evidence seems contradictory: in a time when global warming is touted as one of the forefront international issues, record-breaking cold seems to undermine climate scientists’ claims that the earth is rapidly warming. Does the polar vortex contradict global warming?
To put it simply, the answer is no. In fact, global warming likely played a role in contributing to the polar vortex phenomenon.
The polar vortex itself is a circular flow of low pressure and cold air that forms around the north pole in the winter, keeping the cold air in the north. At the lower edge of the polar vortex is a jet stream, which is responsible for a lot of the day-to-day weather in the United States. During the winter months, this jet stream can weaken and send frigid arctic air southward.
How does global warming factor into the polar vortex phenomenon? Greenhouse emissions have increased the global temperature by 1.8° F overall, and it is estimated that this number doubles when looking specifically at arctic regions. Temperatures and air pressure levels in the north and south poles are beginning to look more like non-arctic regions of the globe. Higher temperatures and changes in air pressure result in a weaker jet stream, which causes the polar vortex as described above.
The distinction between weather and climate is an important one: the weather you experience on an everyday basis is generally local and not indicative of climate, which is based on global data accrued over a longer period of time. The bottom line? Your daily forecast is not the best place to look for evidence of climate change.