Environment

Prophet of the polar vortex

Jennifer Francis was one of the first climate scientists to connect a warmer Arctic with severe winter weather further south

March 21, 2022
A lineman is working at the top of an electric wire pole while a colleague stands below in the snow.
Linemen work to restore electricity in Texas after 2021’s winter storm Uri. [Credit: Jonathan Cutrer | CC BY NC 2.0]

Jennifer Francis’ long relationship with the extremes and vagaries of Arctic weather began in a sailboat. In 1985, during an extended break from college, she and her husband-to-be completed a five-year sailing adventure that took them to places like Cape Horn, around the bottom of New Zealand and, eventually, above the Arctic Circle.

“At the time, we were told that we’ve gone farther north than any other American sailboat,” Francis says. The couple’s biggest challenge — more than lacking modern amenities like GPS or cellphones — was that the further north they went, the less reliable weather forecasts became.

“Weather really controls your life when you’re living on a sailboat,” Francis explains. And accurate information about weather in the Arctic was sorely lacking.

 Francis resolved to fill that gap. Today, as a senior scientist at the Woodwell Climate Research Center in Falmouth, Massachusetts, she’s one of the world’s most prominent experts on the polar vortex. This phenomenon is at least vaguely familiar to any American who witnessed last year’s Winter Storm Uri, which killed hundreds of people in Texas and caused more than 4 million homes to lose electricity during a brutal storm.

Francis describes the polar vortex as a “spinning top” of cold air that normally hangs over the Arctic, but sometimes breaks into multiple mini-tops of freezing air that descend over North America, Europe and Asia.

Almost exactly a year ago in February 2021, the polar vortex broke apart for nearly the whole winter and the U.S. saw firsthand the weather chaos that can follow. At that time, one offshoot descended over North America as far as Texas. Temperatures there plunged 40 degrees Fahrenheit below normal and news reports asked the increasingly common question: Was this climate change?

Francis appeared again and again in news stories about the deep freeze, in large part because she was one of the first scientists to link more frequent polar vortex disruptions to climate change. About 10 years ago, she began studying how rapid warming in the Arctic might have a ripple effect on lower latitudes. While Francis says it’s too soon to know if climate change played a direct role in last February’s freeze, she suspects global warming will increasingly disrupt the polar vortex and send bursts of intense cold southward.

“Other things can disrupt the polar vortex too, but it’s a very hot area of research,” she says, adding that the Texas storm is “consistent with the kinds of things we expect to see happen more often.”

Francis didn’t set out to become a climate scientist, although growing up in a small sailing town on the coast of Massachusetts did give her an early love of weather-watching. In school she wanted to study dentistry, but changed her mind after her round-the-world sailing journey. When Francis returned to dry land, she switched majors and joined the meteorology department at San José State University, which had a treasure trove of data from the Arctic. It wasn’t until Francis moved on to graduate school at the University of Washington, however, that she connected this research with climate change.

Like her circumnavigation of the globe, Francis’ research pushes boundaries. By now, she’s researched climate change in the Arctic for nearly 30 years, but her breakout moment came in 2012. That year, Francis and Stephen Vavrus, an atmospheric scientist at the University of Wisconsin, published a paper proposing a connection between the warming Arctic and severe winter storms further south.

The Arctic is heating up twice as fast as the rest of the planet. This shrinking temperature difference between the Arctic and the lower latitudes, Francis and Vavrus suggested, was causing the jet stream, a band of west-to-east winds in the Northern Hemisphere, to slow and become “wavy”— a meandering river rather than a fast, straight channel. Usually the jet stream keeps the polar vortex in the Arctic, but these waves in its circulation allow frigid northern air to dip southward into warmer latitudes.

Upon publication, their research landed on the New York Times front page. It was a “hairpin turn” in her career, Francis says. “From that moment on, I became a science communicator.”

In 2014, a severe polar vortex event across the Eastern U.S. drew more attention to their work, as well as criticism from other researchers. Several eminent climate scientists wrote in Science that while Francis and Vavrus’ paper put forward “an interesting idea,” it lacked supporting evidence.

Francis and Vavrus are the first to say their 2012 paper represented preliminary findings. They did put the idea forth before having strong evidence, Vavrus explains, and hoped the idea would spark further research. They never expected their work to get so much media coverage at such an early stage.

“I was never happy with that order,” he says. “Probably, Jennifer wasn’t either.”

One of the authors of the cautionary Science letter, John Walsh, a chief scientist at the University of Alaska’s International Arctic Research Center, says they weren’t ruling out a connection between Arctic warming and extreme weather at the mid-latitudes. Rather, they wanted to point out other potential factors.

Before, Walsh says, the “party line in climate science” was that the tropics were responsible for everything that happened in the mid-latitudes. “That did start to shift when Jennifer and Steve Vavrus began publishing papers suggesting that the Arctic might be having a role,” he says. “I think Jennifer deserves a lot of credit for putting the idea forward.”

Judah Cohen, director of seasonal forecasting at the company Atmospheric and Environmental Research, agrees. He recently led a study reviewing current research on Arctic warming and mid-latitude weather. (Francis and Vavrus were among the co-authors.) He found that there are still two camps: one saying the Arctic significantly influences extreme winter weather, and the other camp saying it doesn’t — at least not much.

Cohen concluded that one reason this divide persists is that the computer models many researchers use to depict interactions between different parts of the climate don’t agree with the latest temperature measurements from the Arctic. He also says these models should incorporate more research on how the stratosphere — the second layer of the atmosphere that’s about seven miles aboveground and home to the polar vortex — interacts with the lower troposphere, where our day-to-day weather occurs.

That’s one of the topics Francis is studying these days as she thinks up new ways to measure and categorize different types of polar vortex disruptions.

Along the way, she’s communicating this complex science to the public. Since her now-famous 2012 paper, Francis has been quoted in scores of news stories, and has testified at three Congressional hearings on climate change. Despite lingering controversy over her own research, Francis is heartened by growing acceptance of climate science overall, from both the general public and politicians.

She thinks winter storms like the one in Texas are building public acceptance. “Climate change is affecting people directly through these various types of extreme weather events,” she says.

The rapidly warming Arctic affects everyone indirectly too, through melting glaciers and sea level rise as well as additional carbon dioxide and methane escaping into the atmosphere from thawing permafrost. But extreme weather — the kind that freezes a whole state’s electric grid — is much more personal.

“By connecting to people’s lives,” Francis says, “We’ve gained some traction in helping make climate change a more tangible concept.”

About the Author

Delger Erdenesanaa

Delger is an environment reporter based in Texas. She writes about climate change and related issues in science, politics and economics. Before becoming a journalist she worked in environmental policy and studied Earth science.

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