Antarctic Ice Sheet is Collapsing: Melting Speed to Increase in the Future

It looks like the West Antarctic Ice Sheet is collapsing, and there's very little we can do about it. The ice sheet, which holds enough water to raise global seas by several feet, is now estimated to disappear entirely in just a matter of centuries.

The ice sheet has been threatening to collapse for years now. With warmer temperatures on the rise, the ice has slowly been melting. Now, scientists have taken a closer look at the ice sheet in order to get a better sense of when its disappearance will occur.

"There's been a lot of speculation about the stability of marine ice sheets, and many scientists suspected that this kind of behavior is under way," said Ian Joughin, one of the researchers, in a news release. "This study provides a more quantitative idea of the rates at which the collapse could take place."

In this case, the researchers used detailed topography maps and computer modeling. Although earlier warnings of collapse had been based on a simplified model of ice sitting on an inward-sloping basin, the scientists made more accurate predictions by taking the complex topography around Antarctica into account. Using airborne radar, the researchers imaged through the thick Antarctic ice and combined the data with satellite measurements of ice surface speeds.

"Previously when we saw thinning we didn't necessarily know whether the glacier could slow down later, spontaneously or through some feedback," said Joughin in a news release. "In our model simulations it looks like all the feedbacks tend to point toward it actually accelerating over time; there's no real stabilizing mechanism we can see."

The researchers examined several different melt rates for the ice sheet. The fastest, though, predicted that the ice sheet would begin to rapidly collapse in 200 years. The slowest melt rat kept most of the ice for more than a millennium before the collapse began.

"All of our simulations show it will retreat at less than a millimeter of sea level rise per year for a couple of hundred years, and then, boom, it just starts to really go," said Joughin in a news release.

The findings reveal how the ice sheet is headed to an almost inevitable collapse. If this collapse occurs, we could see a massive rise in sea levels in the future; that's why it's so important to monitor the rate of global warming and take preventative actions.

The findings are published in the journal Science.