The recent cold snap was “highly unusual in the current climate,” and not the product of man-made global warming, a new study found.
But wait, other scientists said the two-weeks of frigid weather and snow in the eastern U.S. was “very much consistent with our expectations of the response of weather dynamics to human-caused climate change.”
The group Climate Central put out a new study countering that claim. Climate Central specializes in an emerging area of research called “attribution” where scientists try to pin specific weather events on man-made warming.
Climate Central’s new study, however, only shows the malleable nature of trying to attribute individual weather events to long-term changes in global climate. The answer to questions of “is this weather the product of global warming” still depends largely on who you ask.
While Climate Central has research suggesting no global warming link, other scientists spent weeks hyping the alleged connection between warming and the recent cold snap.
In a blog post for former Vice President Al Gore’s environmental group, Penn State University climate scientist Michael Mann wrote, “the unusual weather we’re seeing this winter is in no way evidence against climate change,” it’s “an example of precisely the sort of extreme winter weather we expect because of climate change.”
Gore himself promoted Mann’s argument, suggesting the record cold in the eastern U.S. was just global warming.
Mann has often invoked the global warming “consensus” in the past, but his views on extreme winter weather and global warming seem to be outside what the bulk of evidence suggests. While Mann points to individual weather events, long-term weather trend observations — you know, climate — point to the opposite conclusion.
“Such claims make no sense and are inconsistent with observations and the best science,” University of Washington climatologist Cliff Mass previously told The Daily Caller News Foundation. “The frequency of cold waves have decreased during the past fifty years, not increased. That alone shows that such claims are baseless.”
Mann’s argument was largely informed by research by Rutgers University scientist Jennifer Francis, who argues receding Arctic sea ice levels are causing the jet stream to become more wobbly, causing cold spells and nor’easters more persistent along the eastern U.S.
As a nor’easter bore down on the East Coast at the opening of the new year, Francis herself weighed in, and like Mann argued the massive winter storm was consistent with our expectations of global warming. She even said these types of storms could become more common.
“The [ridge/trough] pattern that has prevailed across N. America the past few weeks is entirely consistent with research suggesting a warm Arctic tends to intensify this jet-stream pattern and make it more persistent,” Francis said in an emailed statement.
“We can’t say this particular storm is caused by global warming, but we can say that the persistent ridge/trough pattern, which is one factor in causing nor’easters, is likely to occur more frequently,” she said.
Francis is frequently cited in the media, especially amid the clamor to connect freezing U.S. weather to man-made warming. That fervor was only heightened when President Donald Trump tweeted on the subject — it sent liberal pundits into the stratosphere.
A slew of explainers came out attempting to link cold outbreaks to man-made warming, but as Climate Central’s new study points out, “[c]old waves like this have decreased in intensity and frequency over the last century.”
Indeed, Climate Central’s study seemed to be in line with the bulk of research on the relationship between winter weather and global warming.
“The Climate Central-led study conclusions fit exactly with that consensus opinion: less frequent and severe cold is a consequence of global warming,” Weather.us meteorologist Ryan Maue said in an email.
“Winters will still exhibit extreme cold for decades to come but the historical trend is toward less frequent and extreme cold due to global warming,” Maue said. “This winter has been extremely cold over much of eastern North America and we should still prepare for similar Arctic cold over the upcoming weeks.”
