Melting East Antarctic Ice Could Cause Unstoppable Sea Level Rise for Thousands of Years

It turns out that we may be in for some drastic sea-level rise. Scientists have found that melting on East Antarctica's shore could trigger a persistent ice discharge into the ocean, resulting in unstoppable sea-level rise for thousands of years to come.

"East Antarctica's Wilkes Basin is like a bottle on a slant," said Matthias Mengel, one of the researchers, in a news release. "Once uncorked, it empties out."

The basin itself is actually the largest region of marine ice on rocky ground in East Antarctica. Currently, a rim of ice at the coast holds the ice behind in place. Yet if that rim of ice melts, the "cork" may disappear. This, in turn, could trigger a long term sea-level rise of 300 to 400 centimeters.

"Until recently, only West Antarctica was considered unstable, but now we know that its ten times bigger counterpart in the East might also be at risk," said Anders Levermann, one of the researchers, in a news release. "If half of that ice loss occurs in the ice-cork region, then the discharge would begin. We have probably overestimated the stability of East Antarctica so far."

Melting in this area would make the ground line retreat, which is where the ice on the continent meets the sea and starts to float. The rocky ground beneath the ice actually forms a huge, inland sloping valley below sea-level. This means that when the grounding line retreats, the rim of the ice facing the ocean becomes higher than before. More ice is then pushed into the sea, breaking off and melting. While complete ice discharge would take thousands of years, it would relentlessly continue until the whole basin is empty.

"This is the underlying issue here," said Mengel in a news release. "By emitting more and more greenhouse gases we might trigger responses now that we may not be able to stop in the future."

The findings are published in the journal Nature Climate Change and Climactic Change.