Warming Arctic May Be Causing Jet Stream To Lose Its Way | WAMU 88.5 - American University Radio

NPR : News

Filed Under:

Warming Arctic May Be Causing Jet Stream To Lose Its Way

Mark Twain once said: "If you don't like the weather in New England now, just wait a few minutes."

He was making an unknowing reference to the jet stream, which drives the weather over North America and Europe like a high-altitude conveyor belt. But increasingly, the jet stream is taking a more circuitous route over the northern latitudes, meaning weather systems hang around longer than they used to. And a warming Arctic is probably to blame, says Jennifer Francis, a professor at Rutgers University's Institute of Marine and Coastal Sciences.

Francis — who says it's too early to know if the well-established Arctic warming is caused by man or some natural phenomenon — was speaking during a session on Arctic change at the annual meeting of the American Association for the Advancement of Science in Chicago on Saturday.

The wayward jet stream could account for the persistently severe winter weather this year in the U.S. and Britain, as well as California's long drought.

In all of the talk recently about the "polar vortex," you've already heard some of this. But as Wired U.K. explains:

"The strength of the jet stream is directly proportional to the difference in temperature between the poles and the tropics. When it's strong, the jet stream tends to take a straighter path, but when it's weak it meanders. As the Arctic is experiencing warming at faster rates than the tropics, that difference is getting smaller, so the jet stream is weakening along with it.

"What that means for mid-latitudes, where Britain [and the U.S. are] located, is weather that stays in place for longer. Weather patterns will be more likely to get 'stuck' over a location, yielding long periods of rain and sun rather than Britain's traditional 'changeable' skies."

"The temperature difference between the Arctic and lower latitudes is one of the main sources of fuel for the jet stream; it's what drives the winds. And because the Arctic is warming so fast, that temperature difference is getting smaller, and so the fuel for the jet stream is getting weaker," Francis says. "When it gets into this pattern, those big waves tend to stay in the same place for some time. The pattern we've seen in December and January has been one of these very wavy patterns.

"It doesn't mean that every year the U.K. is going to be in a stormy pattern," she adds. "Next year you could have very dry conditions, and for that to be persistent. You can't say that flooding is going to happen more often. Next year may be dry, but whatever you get is going to last longer."

Mark Serreze, the director of the U.S. National Snow and Ice Data Center, was on the panel along with Francis. He says the idea that changes in the polar north could influence mid-latitude weather, was a new and lively area of research.

"Fundamentally, the strong warming that might drive this is tied in with the loss of sea-ice cover that we're seeing, because the sea-ice cover acts as this lid that separates the ocean from a colder atmosphere," Serreze says.

"If we remove that lid, we pump all this heat up into the atmosphere. That is a good part of the signal of warming that we're now seeing, and that could be driving some of these changes."

Copyright 2014 NPR. To see more, visit http://www.npr.org/.

NPR

Not My Job: Brady Bunch's Florence Henderson Gets Quizzed On Weird Science

For decades, Florence Henderson, who presided over the Brady Bunch, was America's perfect Mom. We'll ask Henderson three questions about the Ig Nobels — awarded for real, if ridiculous, research.
NPR

Tracing A Gin-Soaked Trail In London

Around the world, new gin distilleries are popping up like mushrooms after a rain. NPR traces the boom to its historic roots in London, which once had 250 distilleries within the city limits alone.
NPR

Ranting And Throwing Papers: An Angry Candidate Runs For Congress

State Rep. Mike Bost's rants on the Illinois House floor are the stuff viral dreams are made of. Bost says he has good reason to be upset, and wants voters to share his anger.
NPR

Tech Week: Voice Mail Hang-Ups, Apple Pay And Zuckerberg's Chinese

In this week's roundup, Apple rolls out its mobile payment system but confronts a security test in China, the problem with voice mail messages and Mark Zuckerberg shows off his Mandarin.

Leave a Comment

Help keep the conversation civil. Please refer to our Terms of Use and Code of Conduct before posting your comments.