By Bill Dawson
Texas Climate News
The suggestion that a fierce snowstorm or extreme cold undercuts the almost universal scientific consensus that fossil-fuel pollution is heating up the atmosphere has long been a favorite ploy of some seeking to cast doubt on that conclusion.
No one is more prominently linked to the notion than Jim Inhofe, the Republican senator from Oklahoma who has called manmade climate change “the greatest hoax ever.” In 2010, Inhofe approvingly posted photos on Facebook of an igloo that members of his family built on Capitol Hill with a sign saying “Al Gore’s New Home.” Last year, the senator himself tossed a snowball on the Senate floor.
Whether he’s changed his mind about winter weather’s persuasive power to rebut global warming remains to be seen, but Inhofe didn’t stage any such stunts or make any related pronouncements in the wake of the mammoth blizzard that paralyzed major population centers on the East Coast late last month – at least none that showed up in Google News or that he or his staff liked enough to include in his Facebook or Twitter feeds.
Inhofe did publish an op-ed column last Monday, when Washington was immobilized by snow, arguing that December’s international agreement to slash greenhouse-gas emissions won’t be effective, but it included no effort to debunk climate science.
Climate scientists themselves were busy commenting, however, on the possible links between aspects of global warming, especially warmer-than-usual waters in the Atlantic, and the storm’s severity.
Here’s a reading guide to some of they things they were saying, and journalists were reporting about their research, as Washingtonians, New Yorkers and others were digging out of the snow last week from a weather system that federal experts said was the sixth most severe winter storm to strike the Northeast since 1900.
A blizzard/warming primer
Katharine Hayhoe, a climate scientist at Texas Tech University who’s internationally known for her climate-education efforts aimed at the general public, posted a brief essay on her Facebook page that led off with this question: “There’s a crazy blizzard out there today – does that mean global warming’s not real?!”
Generally warming temperatures don’t mean an end to winter but do mean more evaporation of water from lakes, oceans and rivers, which means more water vapor that can become snow when a winter storm arrives, she wrote.
So, is this blizzard happening because of climate change? No, of course not: it’s winter, and blizzards happen. Does this blizzard mean that global warming isn’t real? No, of course not: although the planet is warming (and 2015 was the warmest year on record to date), there are still plenty of days when it’s cold enough to snow. Did climate change affect this blizzard? Very likely, YES. If ocean and air temperatures had not been so much warmer than average the past month or so, there wouldn’t have been as much water vapor in the atmosphere for this storm to pick up and dump on us.
The ocean-temperature connection
An article by Jake Bleiberg in Vice News explained the meteorological origins of the storm before discussing the ocean-temperature connection.
According to data from National Center for Environmental Information, the ocean waters along the East Coast are several degrees Fahrenheit warmer than their historic average. While this is partially caused by this year’s strong El Niño, Michael Mann, a professor of climate science at Pennsylvania State University, said that rising global temperatures likely also play a role.
Further, Mann suggested that as global temperatures rise so will the likelihood of extreme storms.
“We expect the Atlantic to continue to warm as we continue to increase greenhouse gas concentrations through fossil fuel burning and other activities,” Mann said. “Peer-reviewed scientific studies suggest we are likely to see more of these sorts of coastal storms in the future because of human-caused climate change.”
A slower Gulf Stream current
In a highly detailed article for Mashable, Andrew Freedman examined various factors possibly involved in the recent blizzard and the increasing frequency of heavy snowstorms in the Northeast in general, including the warming of ocean surface temperatures in the Atlantic off the U.S. coastline.
A more novel idea of what’s behind the increase in blockbuster East Coast snowstorms is the slowing down of the Gulf Stream current, which is formally known as the Atlantic Meridional Overturning Circulation (AMOC). Studies show that the Gulf Stream may be slowing down due in part to glacier melt runoff from Greenland.
According to Stefan Rahmstorf, scientist with Germany’s Potsdam Institute for Climate Impact Research who has studied the Gulf Stream slowdown, the weakening of this current has favored the development of unusually mild waters off the East Coast.
Writing for the climate science blog RealClimate, Rahmstorf said the slowdown of the Gulf Stream could set the East Coast up for more years with extreme winter storms, since it favors the continuation of warmer than average waters just off the coast.
Faster ocean warming in the northwest Atlantic
Writing in the Washington Post, Chris Mooney also explored the Gulf Stream issue and its relevance for the northeastern U.S.:
Indeed, there is growing scientific evidence that seas are warming off the U.S. eastern seaboard (especially the Gulf of Maine), and doing so in a way that would seem.
Take, for instance, a study just out in the Journal of Geophysical Research: Oceans, by eleven researchers with the National Oceanic and Atmospheric Administration. They used a high resolution climate model to examine what will happen in the North Atlantic region as global warming proceeds, and found that for a doubling of atmospheric carbon dioxide above pre-industrial levels, the upper ocean waters in the northwest Atlantic continental shelf region would warm “nearly three times faster than the global average.”
The role of rising seas
John Upton, reporting for Climate Central, discussed a recently published study on another factor that may have played a role in magnifying the impact of the storm that struck the Northeast.
“Floodwaters that washed icy brine into streets and homes along the eastern seaboard during [the Jan. 22] blizzard reached heights in some places not experienced since Hurricane Sandy,” Upton wrote, introducing his account of “new research … pointing to an outsized role that ocean warming has been playing in raising sea levels — a problem normally associated with melting land ice.”
The team of scientists … concluded that thermal expansion caused seas to rise globally during the 12 years studied by about two-thirds of an inch, with ice melt and other factors contributing to an overall rise of twice that amount.
Currents, winds, ocean cycles and other factors meant the effects were felt differently in different parts of the world. The East Coast and parts of Asia experienced rapid sea level rise during the study period, while the West Coast saw sea levels drop slightly — albeit temporarily.
The Post’s Mooney had a related article on different research, published today. The newspaper headline: “Why the U.S. East Coast could be a major ‘hotspot’ for rising seas.”
New research published Monday adds to a body of evidence suggesting that a warming climate may have particularly marked effects for some citizens of the country most responsible for global warming in the first place — namely, U.S. East Coasters.
Writing in Nature Geoscience, John Krasting and three colleagues from the Geophysical Fluid Dynamics Laboratory of the National Oceanic and Atmospheric Administration find that “Atlantic coastal areas may be particularly vulnerable to near-future sea-level rise from present-day high greenhouse-gas emission rates.” The research adds to recent studies that have found strong warming of ocean waters in the U.S. Gulf of Maine, a phenomenon that is not only upending fisheries but could be worsening the risk of extreme weather in storms like Winter Storm Jonas [one name given to the blizzard that gripped the Northeast last week].
Katharine Hayhoe is a member of TCN’s volunteer Advisory Board. Members have no authority over editorial decisions.
Bill Dawson is the founding editor of Texas Climate News.