Record cold temperatures are once again expected to hit a swath of the country this weekend—even plunging Florida into its coldest stretch of the last 15 years, potentially bringing snow to areas of the state that haven’t seen it in four decades.
This arctic blast is actually a sign of climate change, and how more extreme weather happens in an increasingly warming world, despite erroneous claims by the president and others.
There’s a difference between weather and climate
Ahead of the winter storm that brought intense snow, ice, and freezing temperatures to about two-thirds of the United States earlier this month, President Trump took to Truth Social to repeat a common piece of climate misinformation.
“Record Cold Wave expected to hit 40 states. Rarely seen anything like it before,” he wrote. “Could the Environmental Insurrectionals please explain — WHATEVER HAPPENED TO GLOBAL WARMING???”
Trump repeated this sentiment in a recent speech. But his comments reveal a deep misunderstanding about climate change.
There is a difference between weather and climate. Weather is short, variable, and has to do with the current conditions in any place at a specific time. Climate, on the other hand, has to do with long-term trends and patterns.
As climate change worsens and the planet warms, it leads to trends of hotter and hotter years. But it also exacerbates weather extremes.
Climate change also specifically destabilizes the polar vortex, which then brings arctic air and freezing temperatures further south than usual.
What is the polar vortex?
Swirling around the Arctic above the North Pole is the polar vortex, a large mass of cold, fast winds.
Typically, the polar vortex is pretty fixed in terms of its shape and reach: it sits as a band above the top of the planet, like a hat made of cold, low-pressure air.
The Arctic is the fastest warming region of the planet, and as it warms, it throws the polar vortex out of whack.
Underneath the polar vortex is the polar jet stream, a river of air that sits closer to the Earth’s surface and affects our winter weather. As climate change disrupts and destabilizes the polar vortex, it causes it to wobble and distort out of shape.
That in turn affects the polar jet stream. Instead of blowing its cold winds straight across the Earth, the jet stream turns wavy, curving up and down and bringing storms and frigid Arctic air further south than usual.
That’s what is expected to bring dangerously cold temperatures to much of the country this weekend.
Overall, our winters are still getting warmer. On average, 210 locations around the U.S. now experience six more extremely warm days than they did in the 1970s.
A warmer atmosphere also holds more precipitation, which can even mean more snow. And generally, climate change fuels all sorts of extremes—from more intense hurricanes to hotter heat waves to, yes, more severe winter storms.