Sea ice shrank this year to its second-smallest size since 1979, according to a study from the U.S. National Snow and Ice Data Center.
"The recent sea ice decline … appears to be unprecedented," study author Christian Zdanowicz, a glaciologist at Natural Resources Canada, told the CBC.
"We kind of have to conclude that there's a strong chance that there's a human influence embedded in that signal."
According to Bloomberg, experts say greenhouse gases may be responsible for the ice, which shrinks every summer before expanding again, to 4.33 million square kilometers (1.67 million square miles).
Researchers used ice core records, lake sediment, tree ring data, and historical information to reconstruct previous covers, and found that the the ice's thickness and expanse has declined markedly over the last 30 years.
When ice melts, the ocean surface is exposed and absorbs 90 percent of the light, which heats the water and leads to climate patterns.
“You increase the radiation that’s absorbed by the oceans, that’s one of the strongest climate feedback mechanisms,” Christophe Kinnard, study author and geographer at Centro de Estudios Avanzados en Zonas Aridas in La Serena, Chile, told Bloomberg News in a telephone interview. “The more sea ice you lose, the more energy you get in the ocean, which warms the atmosphere.”
The study appeared Nov. 23 in the journal Nature.
