(CNSNews.com) – In the sea-level-change chapter of the September 2013 United Nations’ International Panel on Climate Change (IPCC) assessment report, two scientists say that if the “ice-cork region” of East Antarctica disappears, all the ice in the Wilkes Basin could drain into the sea – in 10,000 years.
The report, accessible through purchase on readcube.com, used some observations of the ice but relied mostly on climate simulation models, or PISM, to predict what would happen if the “ice cork” between the Wilkes Basin and the open sea in East Antarctica melted.
“The stability of the Wilkes marine ice sheet has not been the subject of any comprehensive assessment of future sea level,” the chapter states. “Using recently improved topographic data in combination with ice-dynamic simulations, we show here that the removal of a specific coast ice volume equivalent to less than 80mm of global sea-level rise at the margin of the Wilkes Basin destabilizes the regional ice flow and leads to a self-sustained discharge of the entire basin and a global sea-level rise of 3-4 meters.”
But if the timeframe for that sea-level rise is difficult to ascertain from the report, an interview with the scientists posted on May 4 on the Climate News Network website reveals that it would take 5,000 to 10,000 years for the entire basin to drain into the sea. That estimate is also based on simulation models.
“For all the ice in the Wilkes Basin to be lost in this way would take 5,000-10,000 years, the simulations showed,” the article states. “But once it had started, the discharge of ice would slowly but relentlessly continue until the whole basin was empty, even if the climate ceased to warm.”
“This is the underlying issue here,” co-author and scientist Matthias Mengel told the Climate News Network. “By emitting more and more greenhouse gases we might trigger responses now that we may not be able to stop in the future.”
“While the sparse existing observations do not indicate warmer water inflow towards the Wilkes ice sheet margin at present, there is no reason why changes similar to those in West Antarctica could not also occur here,” Mengel said.
He further said “some” simulations showed that warm ocean conditions needed to unplug the ice-cork could happen in the next 200 years, but “it would take around 2,000 years to raise global sea levels by one meter”– or about 3 feet.
“We have detected a new and previously overlooked source of sea level rise, therefore these numbers have to be added to the present sea level rise projections of the IPCC,” Mengel said.
“The full sea-level rise would ultimately be up to 80 times bigger than the initial melting of the ice cork,” Anders Levermann, lead author of the chapter, told the Climate News Network. “Until recently, only West Antarctica was considered unstable, but now we know that it’s 10-times-bigger counterpart in the East might also be at risk.”