Sea Ice in Arctic Melting at “Unprecedented” Rate

Arctic sea ice is melting at a pace and magnitude unlike anything the Earth has experienced in the past 1,450 years, a study published online Wednesday in the British journal Nature said.

Christian Zdanowicz, a glaciologist at Natural Resources Canada, who co-led the study said both the duration and magnitude of the current decline in sea ice “seem to be unprecedented…We kind of have to conclude that there’s a strong chance that there’s a human influence embedded in that signal.”

Using ice core records, lake sediment, tree ring data, and historical information, researchers reconstructed the amount of sea ice across the Arctic in the past and discovered that the ice’s thickness and expanse has declined markedly over the last 30 years.

According to Kinnard, multiple factors are to blame for the dramatic loss of sea ice.

“Everything is trending up — surface temperature, the atmosphere is warming, and it seems also that the ocean is warming and there is more warm and saline water that makes it into the Arctic,” Kinnard said adding, “and so the sea ice is eroded from below and melting from the top.”

Previously, sea ice loss was driven by changes in ocean currents and not necessarily by periods of warmer temperatures.

According to Bloomberg, arctic sea ice directly impacts the global climate, since 80 percent of the sunlight that strikes it is reflected back to space.

When the ice melts in the summer, it exposes the ocean surface, which absorbs about 90 percent of the light. Rising ocean water temperature has a direct influence on climate patterns.

“You increase the radiation that’s absorbed by the oceans, that’s one of the strongest climate feedback mechanisms,” Kinnard said. “The more sea ice you lose, the more energy you get in the ocean, which warms the atmosphere.”

via Vancouver Sun