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Antarctic Ice Melt Will Double by 2050, Say Experts

Oct 13, 2015 11:24 AM EDT

Recently, researchers have pointed out that Antarctica's melting hasn't been as intense as many climate change experts had feared. However, new research has revealed that this is all about to change, with new data hinting that the White Continent's surface will double its current melt rate by 2050. 

Specifically, investigators with the Royal Netherlands Meteorological Institute, the Institute for Marine and Atmospheric Research at Utrecht University, the Woods Hole Oceanographic Institution (WHOI) and Clark University combined satellite observations of ice surface melting with the most up-to-date and widely accepted climate simulation models. They ran their numbers accounting for average greenhouse gas emissions by the year 2100, and also with levels expected if ongoing efforts to curb carbon emissions prove a grand (and surprising) success.

Stunningly, even under the least punishing of emissions conditions, the researchers concluded that there is a "strong potential for the doubling of Antarctica-wide ice sheet surface melting by 2050." The results were published in the journal Nature Geoscience.

"Our results illustrate just how rapidly melting in Antarctica can intensify in a warming climate," Luke Trusel, WHOI researcher and lead author said in a statement."This has already occurred in places like the Antarctic Peninsula where we've observed warming and abrupt ice shelf collapses in the last few decades. Our model projections show that similar levels of melt may occur across coastal Antarctica near the end of this century, raising concerns about future ice shelf stability." (Scroll to read on...)

(Photo : Andrew Thurber)

And that's worrying, as past studies have shown that sudden shelf collapses in the White Continent so heavily and suddenly contribute to sea level rise that they can shake the Earth's gravitational field.

This has already occurred in the past, when Antarctica's Southern Peninsula - a region once hailed as 'unaffected by climate change' started to shed ice into the ocean at a nearly constant rate of 60 cubic km - or about 55 trillion liters of water - each year. The melt was so dramatic that it even caused small changes in the gravity field of the Earth, which were detected by the Gravity Recovery and Climate Experiment (GRACE) satellite.

"To date, the glaciers added roughly 300 cubic km of water to the ocean. That's the equivalent of the volume of nearly 350,000 Empire State Buildings combined," investigator Bert Wouters, a Marie Curie Fellow at the University of Bristol, UK, announced last March.

"It appears that sometime around 2009, the ice shelf thinning and the subsurface melting of the glaciers passed a critical threshold which triggered the sudden ice loss," Wouters added. "However, compared to other regions in Antarctica, the Southern Peninsula is rather understudied, exactly because it did not show any changes in the past, ironically." (Scroll to read on...)

(Photo : Pixabay)

These mysterious shelves may wind up being an even more important tipping point in the future. As Trussel and his colleagues point out, while continental sheet melting will at-least double under most emissions scenarios, things get wildly different between 2050 and 2100.

They determined that under the high-emissions climate scenario, ice sheet surface melting will approach or exceed intensities associated with ice shelf collapse in the past. Under the reduced-emissions scenario, however, there is relatively little increase in melting after the doubling by 2050.

"The data presented in this study clearly show that climate policy, and therefore the trajectory of greenhouse gas emissions over the coming century, have an enormous control over the future fate of surface melting of Antarctic ice shelves," said Clark University geologist Karen Frey, "which we must consider when assessing their long-term stability and potential indirect contributions to sea level rise."

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