Quote:Zwally says the problem is that East Antarctica is so enormous even tiny discrepancies can completely change the answer.
“In West Antarctica, you’re looking at bigger changes over a small area,” Zwally says. “And in East Antarctica, you’re looking at smaller changes over a much bigger area.”
Zwally, himself a veteran glaciologist, says the differences stem from how teams treat the density of the ice sheet, which is thousands of feet thick, as well as how the teams analyze the slow movement of bedrock under the ice. According to Zwally, on-the-ground studies have shown that Antarctica has seen unusually heavy snowfall over the last 10,000 years. That weight burdens the ice sheet and gradually makes the ground beneath it sink. These changes have to be accounted for, he says.
“It’s a debate over the methodology, and their methodology is primitive,” Zwally says. “It’s what we were doing 15 years ago, but we’ve advanced beyond that state. We no longer have to guess at that density.”
Zwally still stands by his 2015 study, but in an interview last week, he said nature has recently changed the equation. His team is crunching numbers from the past two years, looking at ice melting and snowfall rates in Antarctica. And they found something startling.
The melt rates in West Antarctica just increased significantly. His calculations now show that the continent is in overall balance. The findings haven’t been peer reviewed yet, but he plans to present them at a science conference later this year.
“In our paper we said that might happen in two to three decades,” Zwally says. “Well, this is an unpublished result, but now we’re very close to the zero line.”
http://blogs.discovermagazine.com/d-brief/2017/05/16/is-antarctica-gaining-or-lo...It was thought that the tipping point for Antarctica was a couple of decades away. Could be here now.
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Is Antarctica about to add to sea level rise? (Read 746 times)
