Sep 26, 2017

The Importance of Ice Thickness in Assessing the Impact of Climate Change in the Arctic

by
Gloria Dickie
,
Pacific Standard
Calved icebergs from the nearby Twin Glaciers are seen floating on the water in Qaqortoq, Greenland. Photo: Joe Raedle, Getty Images
Calved icebergs from the nearby Twin Glaciers are seen floating on the water in Qaqortoq, Greenland. Photo: Joe Raedle, Getty Images

After 16 months of consecutive record and near-record lows in late 2016 and early 2017, sea ice extent in the Arctic held fast over the summer thanks to more moderate weather and cooler temperatures. As of September 13, sea ice covered some 4.64 million square kilometers (1.79 million square miles) at its minimum, roughly 1.25 million square kilometers (482,000 square miles) more than record-setting year 2012.

Still, while 2017’s summer melt season didn’t break the record, it falls far below the 1981 to 2010 median extent by over 1.58 million square kilometers (610,000 square miles). Moreover, surface cover isn’t everything when it comes to the state of the Arctic — what experts say matters most is the total volume of ice — a combination of thickness and extent, and 2017 saw summer volumes among the lowest ever recorded.

Some scientists are now saying colloquially that the Arctic Ocean has in recent decades entered the “Thin Ice Age.” Since 1980, the average ice thickness come July has decreased by an estimated 120 centimeters (47 inches).

Notably this July, the average sea ice thickness in the Arctic was equivalent to the lowest on record.

So in spite of a slight rebound in summer extent, the average Arctic sea ice volume was still 47 percent below the 1979 to 2016 mean. That is not only likely bad news for the future of Arctic ice and polar ecosystems, but also for a stable global climate, which is highly influenced, and possibly unbalanced by events up North.