Andrew Freedman outdid himself on Climate Central with an excellent overview of the scientific debate on the link between Arctic sea ice loss and a wavy jet stream causing weird and extreme weather. Coincidentally (?) there's an "extreme kink" in it right now that just caused the warmest December temperature ever measured at any site on the Alaskan Arctic Ocean shoreline region.
Freedman wrote the piece following the publication in Nature of a new paper - with Jennifer Francis as co-author - that claims that rapid Arctic warming has an influence on extreme summer weather events. The last couple of years a lot of pioneering research is being done in this area, which in my view is one of the most exciting and important scientific corners currently around. Which explains why more and more experts are keeping an eye on developments.
Study Adds to Arctic Warming, Extreme Weather Debate
A new study for the first time found links between the rapid loss of snow and sea ice cover in the Arctic and a recent spate of exceptional extreme heat events in North America, Europe, and Asia. The study adds to the evidence showing that the free-fall in summer sea ice extent and even sharper decline in spring snow cover in the Northern Hemisphere is reverberating throughout the atmosphere, making extreme events more likely to occur.
The study, published Sunday in the journal Nature Climate Change, is the first to find correlations between rapid Arctic warming and extreme summer weather events, since previous research had focused on the links between Arctic warming and fall and winter weather patterns.
While the study adds to the body of evidence pointing to the outsized role the Arctic is playing in shaping weather patterns, it won't end the debate within the scientific community over whether and how what is happening in the Far North could be having such far-reaching impacts.
There is virtually no controversy among climate scientists and meteorologists that massive changes have occurred in the Arctic environment during the past three decades, and that those changes are largely due to manmade greenhouse gas emissions.
Since the 1980s, Arctic sea ice extent has dropped at a rate of about 8 percent per decade during September, which is when the sea ice cover reaches its annual minimum. A record minimum was set in 2012. For a size comparison, consider that the area of summer sea ice lost since the 1980s would cover about 40 percent of the continental U.S., the study said.
Spring snow cover extent loss during June has dropped even more precipitously than sea ice cover, the study found, at a rate of about 18 percent per decade since 1979.
The reasons why the Arctic is warming so quickly — a phenomenon known as Arctic amplification — has to do with factors that are unique to the Arctic environment, involving feedbacks between sea ice, snow, water vapor and clouds. As the area warms in response to manmade greenhouse gases, melting ice and snow allow exposed land and water to absorb more of the Sun’s heat, which melts more ice and snow, and so on. A relatively small amount of initial warming can be greatly magnified in the Far North.
It is also widely agreed that the world has seen a spate of extreme heat events in recent years, such as the 2011 Texas heat wave and drought and the deadly 2010 heat wave in Russia, and that global warming made some of these events more likely to occur and more severe.
But scientific consensus breaks down when it comes to the issue of whether Arctic warming is altering weather patterns in the northern midlatitudes, stacking the deck in favor of extreme weather events.
On one side of the issue are some meteorologists and climate scientists who in their studies have found correlations between the vanishing Arctic sea ice and snow cover (collectively known as the cryosphere) and weather patterns that can lead to extreme weather events.
On the other side are other climate scientists and meteorologists who, while convinced that manmade climate change is having profound impacts on the planet, don’t yet see clear physical science evidence showing that Arctic warming is changing the already chaotic nature of weather patterns, and leading to extreme weather events.
James Overland, a researcher at the National Oceanic and Atmospheric Administration (NOAA), said the split in the scientific community is an unusual one.
This piece is getting even more interesting, go read it over at Climate Central.