Getting Hotter and Colder: Explaining the Polar Vortex

Getting Hotter and Colder: Explaining the Polar Vortex

by Elizabeth Clarey


We endured a bitterly cold couple of weeks last month here in Central Europe – a difference from the milder winters I’ve come to expect. In the US, blizzards and record-low temperatures reached across the country this winter to states as far south as Mississippi and Texas. In January, Central Asia experienced unusually cold temperature for most of the month. Climate-change naysayers like to use instances of extreme cold as evidence that global warming is a hoax, but it may be precisely because of global warming that we are experiencing extreme temperature drops. So, what’s going on here?

You’ve probably heard about the polar vortex, which is defined as a band of icy-cold westerly winds that form around the North Pole during the winter months when little or no sun reaches the area. The polar vortex forms about 10 to 30 miles above the ground in a layer of the atmosphere called the stratosphere. The polar vortex interacts with something called the polar jet stream, which is a current off warm air that sits below the vortex, about 5-9 miles above the ground.

A strong, stable polar vortex swirls in place above the North Pole, with the coldest air circulating steadily at the top of the globe and the milder air staying at a lower latitude. An unstable polar vortex, however, can slide off the north pole, split into different lobes, wobble, or reverse direction. If this happens, the polar jet stream morphs into a wave-like shape around the globe, with warmer air pushing north in the peaks and arctic air pushing south in the valleys. These wave-like patterns move slowly from east to west, resulting in weeks of frigid weather.

Some scientists believe that global warming might be causing these unstable polar vortex events. The arctic is warming four times faster than other parts of the planet, with severe disruptions to the usual snow cover and sea ice in the region. This “Arctic amplification” is hypothesized to be a cause of knocking the polar vortex off kilter. Records have shown that the number of extreme cold weather events is decreasing overall. However, when cold snaps happen, they will continue to be very intense.

This is troubling news for many areas in the Northern Hemisphere, especially those that are not accustomed to cold and snow. Temperate places often do not have the infrastructure or resources to address how severe cold might impact transportation, energy usage, and agriculture. One such example of the devastating societal and economic impacts of the polar vortex happened in Texas, in 2021, when temperatures in the state dipped 40 degrees (fahrenheit) below normal. The weak polar vortex that year caused a cold snap that resulted in the largest power crisis in the state’s history, which led to shortages of food, water, and heat. This is because power sources in the state were not properly winterized, causing a grid failure.

Predictably, a polar vortex will stress energy systems, as people and businesses use more heat to stay warm. Cold weather also disrupts transportation systems and makes roads difficult and dangerous to travel – especially when locals don’t have experience driving in such conditions. In addition, the cold weather could severely affect crop yield and production. Freezes caused by a polar vortex can have devastating effects on wildlife. 3.8 million fish were estimated to have died because of the Texas freeze, and sea turtles on the Gulf Coast were “cold stunned” which made them unable to navigate to warmer waters.

The weaknesses of the polar vortex show us that we all must be prepared for both extreme hot and extreme cold as the climate continues to change. Governments must invest in weatherizing energy systems, building housing that can withstand both low temperatures and high heat, (especially for populations that are most vulnerable) and develop effective alert systems to help people prepare for such weather events.