Alaska has experienced significant warming over the past three decades and melting sea ice in the Arctic Ocean seems to be the cause, say researchers from the Arctic Climate Research Center (ACRC) in Fairbanks, Alaska.
The authors, publishing in The Open Atmospheric Science Journal, found that annual temperatures in Barrow, the state's northern most settlement, increased by 4.86 degrees Fahrenheit (2.7 degrees Celsius) from 1979 to 2012.
The most dramatic increase occurred in October with temperatures rising by 12.96 degrees Fahrenheit (7.2 degrees Celsius). Average temperatures in November also rose significantly — 11.34 degrees Fahrenheit (6.3 degrees Celsius) over the 34-year period.
The October temperature increase corresponded to the highest yearly amount of sea ice loss in the Beaufort and Chukchi Seas, located north of Alaska. The amount of open water in October increased by 44 percent for the Beaufort Sea and by 46 percent for the Chukchi Sea.
"It definitely surprised me, especially the very strong decrease in the sea ice and the warming of the area," study author Gerd Wendler, professor emeritus of geophysics at ACRC, told VICE News.
On the bigger scale of global climate change it is a relevant study because it provides factual evidence about a big climate change signal occurring in Alaska.
Wendler and his team found that January temperatures actually decreased by an average of 2.88 degrees Fahrenheit (1.6 degrees Celsius) over the 34-year time span. That temperature drop corresponded to an increase in the average January sea ice extent, highlighting the possible link between temperature and the amount of sea ice in the Arctic.
Sea ice helps trap heat in the ocean. But when sea ice melts the ocean's heat is released into the atmosphere, which in turn contributes to more sea ice melt — a vicious feedback loop that scientists call the "Arctic amplification."
Since the 1980s, temperatures in the Arctic have increased twice as fast as the rest of the world, according to the UN Intergovernmental Panel on Climate Change. Annual average Arctic sea ice extent, says the agency, has shrunk by nearly 13 percent per decade and the ocean could become ice-free during the summer by the end of the century.
The warming in northern Alaska is already bringing about an increase in wildfires, Wendler told VICE News.
"I think it is certainly an important study for people who live in the coastal regions affected by this sharp decline in summer sea ice," David Holland, Director of the Center for Global Sea Level Change at NYU's Courant Institute of Mathematical Sciences, told VICE News. "On the bigger scale of global climate change it is a relevant study because it provides factual evidence about a big climate change signal occurring in Alaska."
Holland was not a participant in the ACRC study.
Wendler said that the sea ice loss is likely the reason behind the temperature increase, as opposed to other factors like greater amounts of incoming solar radiation.
"Solar radiation is weak in October so it couldn't have caused the temperature increase," he told VICE News.
Previous research has found a link between human-induced climate change and the decline in sea ice in the Arctic. In 2012 researchers at Germany's Max Planck Institute for Meteorology found that increased greenhouse emissions, and not natural fluctuations, can explain the ice loss in the Arctic.
"In the end, only the increase in greenhouse gas concentration showed a physically plausible link with the observed sea-ice retreat," said Dirk Notz, the study's lead author.
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