The hulking West Antarctic ice sheet has been worrying scientists for decades. Global warming, as we already know, is causing very massive glaciers to melt a very rapid pace. But if this ice sheet goes, as some climate models have formidably simulated, sea levels could rise by as much as 12 feet. That's enough to flood 28,800 square miles of coastal land in the United States alone.
For many experts, the question isn't if this is going to happen, but when.
Since the 1950s, West Antarctica's glaciers have been called "unstable," "unstoppable," and the region's "weak underbelly" by researchers who recognized their unique vulnerabilities and immense potential for catastrophe.
In particular, the Thwaites and Pine Island glaciers near the Amundsen Sea are of utmost concern because they possess the ability to destabilize the entire ice sheet, setting off a careening chain of events. According to Washington Post, while both glaciers are capable of causing up to two feet of sea level rise, each depositing nearly "45 billion tons of ice into the ocean annually," their structural integrity makes them especially dangerous.
Unlike other glaciers, which are "pinned" down by islands or other landmasses, Thwaites and Pine Island are more or less latched onto an underlying seabed, exposing them to warming ocean currents. Thwaites glacier, explained Science, "has a wide front on the ocean's edge and sits on ground below sea level, where warming waters can slowly melt its base. This deep seawater is held back by a submerged ridge, but once water surmounts this grounding line, the land slopes downward into a basin of uncertain topography and slipperiness."
Two papers, published in 2014 to Geophysical Research Letters and Science, used climate models to map out the thinning of these glaciers over the last two decades, laying out what scientists had been predicting for years.
A newer study, published last year to the Proceedings of the National Academy of Sciences, went even further, modeling the exponential collapse of the entire ice sheet, starting with currently melting along the Amundsen Sea. What the study confirmed, according to Ian Joughin, co-author of the previous year's Science paper, was that "knocking out the Pine Island Glacier and Thwaites takes down the rest of the West Antarctic Ice Sheet."
While the papers came to similar conclusions regarding the hypothetical outcome of such a glacier collapse, they disagreed on exact timelines. Whether we should be looking at centuries or millennia remains unclear.
Thankfully, an upcoming collaboration between the National Science Foundation and the Natural Environment Research Council hopes to answer that question. "Satellite measurements indicate that the rate of ice loss near the Thwaites Glacier has doubled in six years, and now accounts for about 10 percent of global sea level rise," the agencies said in a joint statement announcing their partnership.
Together, both will dedicate up to $25 million to understand the consequences and urgency of these events, with specific emphasis on Thwaites glacier.
"Recent studies indicate that the greatest risk for future rapid sea-level rise now comes from the Thwaites Glacier due to the large changes already underway, the potential contribution to sea-level rise, and the fact that a collapse could occur within decades or centuries—a remarkably rapid change in relatively short geological time."
Fieldwork at Thwaites glacier will begin in 2019 and extend through 2020, the agencies added. Projects will involve researchers from both the United States and the United Kingdom, and will include modeling to predict ice loss in the West Antarctic ice sheet.
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