Friday, 10 June 2016

Jason Box on the Greenland ice melt

Jason Box on Greenland Melt 2016

Not Greenland. This is the Beaufort Sea

Fourth heat wave in southwest #Greenland this year means we're 1.5 months of melt ahead of 2015 when we counted in cm.

Below, new research underlines Dr. Box’s observations and concerns.

University of Sheffield:
Following record-high temperatures and melting records that affected northwest Greenland in summer 2015, a new study has provided the first evidence linking melting in Greenland to the anticipated effects of a phenomenon known as Arctic amplification.
Arctic amplification is the faster warming of the Arctic compared to the rest of the Northern Hemisphere as sea ice disappears.
It is fuelled by a feedback loop: rising global temperatures are melting Arctic sea ice, leaving dark open water that absorbs more solar radiation which in turn warms the Arctic even more.
Arctic amplification is well documented, but its effects on the atmosphere are more widely debated.
One hypothesis suggests that the shrinking temperature difference between the Arctic and the mid-latitudes will lead to a slowing of the jet stream, which circles the northern latitudes and normally keeps frigid polar air sharply separated from warmer air further south.
Slower winds could create wilder swings of the jet stream, allowing warm, moist air to penetrate further north.
The new study, published in Nature Communications and conduct by researchers from the University of Sheffield and Columbia University’s Lamont-Doherty Earth Observatory, among several other institutes, shows that those anticipated effects occurred over northern Greenland during the summer of 2015, including a northern swing of the jet stream that reached latitudes never before recorded in Greenland at that time of year.
Edward Hanna, Professor in Climate Change in the Department of Geography, University of Sheffield, said: “Our results show the effects of a strongly warming Arctic and disturbed atmospheric jet stream on causing a record melt of the far northern reaches of the Greenland Ice Sheet last summer.

The study is closely linked to ongoing work conducted at the University of Sheffield which analyses the connection between Arctic climate change and extreme weather events across the densely-populated northern hemisphere mid-latitudes.”
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