Temperatures Possible This Century Could Melt Parts of East Antarctic Ice Sheet, Raise Sea Levels 10+ Feet
A section of the East Antarctic Ice Sheet that contains three to four meters (approximately 10 to 13 feet) of potential sea level rise could melt if temperatures rise to just two degrees above pre-industrial levels, a study published in Nature Wednesday found.
Researchers at Imperial College London, the University of Queensland, and other institutions in New Zealand, Japan and Spain looked at marine sediments to assess the behavior of the Wilkes Subglacial Basin during warmer periods of the Pleistocene and found evidence of melting when temperatures in Antarctica were at least two degrees Celsius above pre-industrial levels for periods of 2,500 years or more.
"With current global temperatures already one degree higher than during pre-industrial times, future ice loss seems inevitable if we fail to reduce carbon emissions," Imperial College researcher Dr. David Wilson said in a University of Queensland press release published by ScienceDaily.
The East Antarctic Ice Sheet has been considered less susceptible to melting than the West Antarctic Ice Sheet because its basin is largely above sea level, but the Wilkes Subglacial Basin is below sea level and therefore more vulnerable, University of Queensland researcher Dr. Kevin Welsh said in press release.
"The evidence we have suggests that with the predicted two degrees Celsius warming in Antarctica—if sustained over a couple of millennia—the sheet would start melting in these locations," Welsh said.
Wilson told The Washington Post that the earth could see temperatures this century that would be warm enough to start the melting process eventually, but the study did not indicate how fast or slow that process would be.
"What we definitely can say is that during the [geological] stages where temperatures were warm for a couple of degrees for a couple of millennia, this is where we see a distinct signature in our records," Wilson told The Washington Post. "We can't necessarily say things didn't happen quick, but we can't resolve that in our data."
During one of the periods studied, around 125,000 years ago, sea levels were 20 to 30 feet higher than they are now, The Washington Post reported.
University of California at Irvine glaciologist Isabella Velicogna, who was not involved in the study, told The Washington Post that it "contributes to the mounting pile of evidence that East Antarctica is not as stable as we thought."
The Paris agreement seeks to limit warming to "well below" two degrees above pre-industrial levels, but current efforts are not sufficient to meet this goal, according to an International Energy Agency report released in March.
Another study released this week offers a back-up plan: underwater walls of rock and sand to stop glaciers from sliding and collapsing and to protect them from the warmer ocean water that accelerates melting.
The study, published in the Cryosphere Thursday, used modeling to assess the impact of various geoengineering projects on halting the collapse of West Antarctica's Thwaites Glacier, projected to be the greatest individual source of potential sea level rise.
"We are imagining very simple structures, simply piles of gravel or sand on the ocean floor," study author and Princeton University Department of Geosciences researcher Michael Wolovick told The Guardian.
Wolovick said the designs were "within the order of magnitude of plausible human achievements."
They calculated that the smallest design, constructing a series of columns or mounds using about the same amount of material required to build Dubai's Palm Islands, would have a 30 percent chance of preventing the West Antarctic Ice Sheet's collapse.
Building a full wall, a more ambitious endeavor, would have a 70 percent chance of blocking 50 percent of warmer water from reaching the ice.
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