Greenland And West Antarctic Ice Sheet Loss More Than Doubled In Last Five Years

פורסם: 30 באוג׳ 2014, 0:30 על ידי: Sustainability Org   [ עודכן 30 באוג׳ 2014, 0:31 ]
by Joe Romm Posted on August 22, 2014


Map of elevation change in Greenland between January 2011 and January 2014. Red indicates area where the ice sheet lost mass in this period, while blue represents ice gains. Map: Helm et al.

A new study finds that both the Greenland ice sheet and West Antarctic Ice Sheet (WAIS) have seen an astonishing increase in ice loss in just the past five years.

This first-ever extensive mapping of the two great ice sheets using the CryoSat-2 satellite confirms the findings of several recent studies that “suggest that the globe’s ice sheets will contribute far more to sea level rise than current projections show,” as NASA glaciologist Eric Rignot said recently.

Comparing the current CryoSat-2 data with “those from the ICESat satellite from the year 2009, the volume loss in Greenland has doubled since then.” Coauthor and glaciologist Prof. Dr. Angelika Humbert further explained in the news release:

“The loss of the West Antarctic Ice Sheet has in the same time span increased by a factor of 3. Combined the two ice sheets are thinning at a rate of 500 cubic kilometres per year. That is the highest speed observed since altimetry satellite records began about 20 years ago.”

So we are at record rates of ice loss now. What is particularly stunning is that a major international study found in 2012 that Greenalnd’s ice loss was up by a factor of five since the mid-90s, while Antartica’s was up 50 percent in the prior decade.

We are seeing ice sheet loss at rates not imagined even a few years ago. Back in May, two studies provided evidence that the West Antarctic Ice Sheet has begun an irreversible process of collapse, in part because its key glaciers are grounded below sea level and are melting from underneath.

Also in May, a team of researchers reported that the Greenland ice sheet has a similar warming-driven instability. As a lead author of that study explained, “The glaciers of Greenland are likely to retreat faster and farther inland than anticipated — and for much longer.”

It’s increasingly clear that if we don’t reverse carbon pollution emissions trends ASAP, sea level rise will likely be 4 to 5 feet or more by century’s end. Also, the rate of sea level rise in 2100 could be upwards of 1 inch per year.

We don’t have any idea of how to adapt cities, ports, and infrastructure to such a rate of sea level rise. As the New York Times reported in May, we are risking “enough sea-level rise that many of the world’s coastal cities would eventually have to be abandoned.”

The whole notion of “glacial” change as a metaphor for change too slow to see is vanish in a world where glaciers are shrinking so fast that you can actually watch them retreat and then disappear (see “Greenland’s Fastest-Moving Glacier Sets New Speed Record Of 150 Feet A Day”).

A growing number of major glaciers are moving faster than America’s climate policy, which, sadly, still isn’t saying that much….