New Calculations for Polar Ice

A new report from the University of Washington, in Seattle, published in the journal Science on polar ice sheets in Greenland and Antarctica, works to reconcile differences between sometimes-conflicting research studies. Scientists compiled 20 years of data to determine how much ice is being lost and sea levels have increased as the global climate warms.

Past studies have shown a range of ice losses, from zero to catastrophic. When the data was synthesized and analyzed holistically, it became clear that the ice sheets are losing three times as much ice each year as they did in the 1990s—in the middle of previous estimates.

Ice sheets are one of several main drivers of rising sea levels. Other factors, which account for 80 percent of the increase, include the melting of glaciers on land and the expansion of the sea itself as the atmosphere heats up. The melting of polar sea ice has no direct effect on sea levels because the ice is already in the water.

Glaciologist and co-author Ian Joughin told The Christian Science Monitor, “The melting needs monitoring to further understand the ice sheet processes leading to the change.”