Antarctica's 'Doomsday Glacier' melting faster than scientists initially thought

Scientists have sounded the alarm on the "aggressive" melting of Thwaites Glacier, the planet's widest glacier, saying it could double the rise in global sea level. 

The glacier, estimated to be as large as Florida, or about 1.5 times bigger than the whole of Luzon, was nicknamed Doomsday Glacier because of the potential global catastrophe its melting would trigger. 

According to an article published on Nature Communications on Oct. 12, the glacier is a big driver of unpredictability in terms of global sea levels. 

"Thwaites Glacier is a major contributor to Antarctic mass loss and a key source of uncertainty in future sea-level rise," the abstract read. 

Currently, the melting glacier makes up about 4% of global sea level rise. It contains enough water that if the entire glacier were to collapse, it would raise sea levels by more than two feet.

However, it isn't just the Doomsday Glacier the world has to contend with. Thwaites is positioned so that it blocks the vast Antarctic ice sheet. If the glacier gives way, it can bring up global sea levels to around 10 feet, which may decimate coastal communities, including Manila. 

While scientists still cannot definitively predict the glacier's future, a team of glaciologists from the University of California, Irvine and NASA's Jet Propulsion Laboratory have put together new ice sheet models that can give them a better idea of the activity underneath Thwaites.

The team's report published by the International Cryosphere Climate Initiative described how the tides allow seawater to constantly flush in and out of the glacier's thick ice; a phenomenon they referred to as a "grounding zone," which could sometimes stretch for miles. Relatively warmer than the glacier, the seawater can then go "deep underneath the ice sheets and causing vigorous melting," said UCLA project scientist and the report's lead author Mattia Poinelli, as quoted by CNN. 

From their assessments using the new ice sheet models, the scientists found that even if global warming stayed constant, Thwaites could add up to 1.2 inches of sea level rise by 2100, which is double previous estimates. 

At the rate the melting process of the glacier is going, scientists estimate a 60% chance of Thwaites breaking loose from a large underwater ridge called Mouginot Ridge. This ridge, along with another one, is what is slowing down Thwaites' flowing into the ocean. 

According to Eric Rignot, a professor of Earth system science at UC Irvine, these findings "predict greater risk of and exposure for coastal flooding than anticipated in the coming decades."

Scientists have known "for decades" about the disastrous effects of climate change on the Earth's ice sheets. But with these new developments, they are loudly renewing their call for the world to aggressively cut planet-heating pollution. 

"A mounting realization gained in recent years of what is really happening on the undersides of glaciers like Thwaites is leading to an even greater sense of alarm," said Rignot.