Scientists say there's no definitive mechanism linking the polar vortex and climate change. Polar freeze: It's weather, not climate

Tuesday’s polar vortex has set off a new round in one of the world’s most predictable disputes: Does Extreme Weather Event X prove or disprove climate change?

In short: No.


The crazy weather that plunged almost all of the U.S. into a deep freeze represents a millisecond in long-term planetary climate trends — a rounding error in the calculation of mean global temperature.

( PHOTOS: Deep freeze: Winter weather across the U.S.)

But that hasn’t stopped some on the right, such as Matt Drudge and Sen. Ted Cruz (R-Texas), from seizing on the extreme chill as evidence against global warming, much as some climate advocates have pounced on disasters like Hurricane Sandy as ammunition for their side.

Sen. Jim Inhofe (R-Okla.) took to the Senate floor Monday to describe the idea of human-induced climate change as “almost laughable,” citing this week’s cold snap and the recent stranding of a Russian research ship in the Antarctic ice. Inhofe has plowed this ground before: After snow buried D.C. in early 2010, his family built an igloo near the Capitol with a sign reading, “Al Gore’s new home.”

Cruz similarly singled out the former vice president Tuesday, telling reporters: “It’s cold. Al Gore told me this wouldn’t happen.”

( Last week on POLITICO: Winter weather in Washington)

Last week, the Drudge Report placed a photo of a minus-40-degrees thermometer under the banner headline “‘GLOBAL WARMING’ INTENSIFIES.”

Snark aside, individual weather events are local and transient, while trends in the Earth’s climate play out over decades and centuries. “Global warming isn’t expected to abolish winters in the U.S. anytime soon,” The Washington Post’s Wonkblog noted this week, while pointing out that the globe consists of more than just the United States.

And most climate researchers say the great weight of the long-term trends points to the reality that big changes are afoot: For example, the National Oceanic and Atmospheric Administration says that according to global temperature data going back to 1880, all 10 of the warmest years on record have occurred since 1998. In May, NOAA announced that carbon dioxide concentrations in the atmosphere had reached a threshold that hasn’t been prevalent on the planet for millions of years.

( Also on POLITICO: Obama 'obviously aware' of cold)

Of course, climate activists have also been quick to cite individual hurricanes, heat waves, droughts — and, yes, extreme cold — as signs that global warming is occurring, even if they usually offer the caveat that it’s impossible to prove that worldwide trends caused an individual weather event.

After Hurricane Sandy, Gore called the storm “a disturbing sign of things to come,” warning that “dirty energy makes dirty weather.” After Hurricane Irene menaced the East Coast in 2011, activist Bill McKibben wrote in The Daily Beast that “Irene’s got a middle name, and it’s Global Warming,” before segueing to the debate over the Keystone XL pipeline.

( Also on POLITICO: Icy grip on air travel begins to ease)

Some scientists offer a scenario that climate change may have played a role in this week’s icy weather, though the jury remains out on that question. The website Climate Central laid out that case on Monday, writing that “Arctic warming is altering the heat balance between the North Pole and the equator,” which can affect the jet stream in ways that might cause unusual weather patterns like what we’re seeing now: “relatively mild conditions in the Arctic at the same time dangerously cold conditions exist in vast parts of the lower 48.”

Even many climate scientists are not convinced that the weather patterns in the Arctic are triggering extreme weather in other parts of the globe, and they say no definitive mechanism linking the two has been proven yet, Climate Central reported.

Michael Mann, the Penn State climatologist who has often been at the center of the fights over global warming, accused climate skeptics of using “discredited talking points” in hopes of “hijacking the serious conversation we need to have about how we are going to deal with the very real risks of climate change.”

Mann told POLITICO that much of the news media’s weather coverage has put the chill in the proper context — showing that record heat incidents are outpacing record cold temperatures by a 3-to-1 margin, and that this past November was the warmest on record for that month.

Still, he said, it’s all too easy to wield a single piece of evidence to try to prove a point.

“In our discourse in this issue we do unfortunately all too often fall for the fallacy that lies in the signal data point, the cherry-picked statistic, rather than focus on the larger picture,” he said. That larger picture, he said, was that climate change was occurring, and it represents a major threat if not addressed.

Two-thirds of Americans believe that climate change is occurring, according to recent surveys. But less than half believe the evidence definitively shows humans are responsible.