Antarctica's ice sheet is melting 3 times faster than before

Ian Joughin  IMBIE

For the total period from 1992 through the present, the ice sheet has lost almost 3 trillion tons of ice, equating to just under 8 millimeters of sea level rise.

"What we have seen as the climate has warmed is that more warm water is reaching the Antarctic ice sheet and that's what is melting the sea ice", he said.

Another study in Nature on Wednesday found that East Antarctic ice sheet didn't retreat significantly 2 million to 5 million years ago when heat-trapping carbon dioxide levels were similar to what they are now.

But 40 per cent of that increase came from the last five years of the study period, from 2012 to 2017, when the ice-loss rate accelerated by 165 per cent.

West Antarctica lost 159 billion tons of ice a year from 2012 through 2017, compared with just 65 billion tons from 2002 through 2007.

The new findings are the result of the most complete satellite survey of Antarctic ice sheet change to date, involving 84 scientists from 44 global organizations (including NASA and the European Space Agency).

However, he said that there is growing evidence that projections of Antarctica's influence on sea-level rise may have been underestimated. Satellite altimeters measure the height of the ice sheets, to see how much they are thinning or thickening over time.

"The increasing mass loss that they're finding is really worrying, particularly looking at the West Antarctic, the area that's changing most rapidly and it's the area that we're most anxious about, because it's below sea level, " said Christine Dow, a glaciologist at the University of Waterloo in Canada who was not involved in the research.

What's happening in East Antarctica is extremely important because it has by far the most ice to give, being capable of raising sea levels by well over 100 feet.

NOAARapidly rising sea levels that inundate the coastlines where billions of people live is one of the more worrisome concerns associated with climate change.

However, if emission were low, the ice shelves would remain intact, Antarctica would make a small contribution to sea level rise, and the continent would remain a "natural reserve, dedicated to peace and science" as agreed by Antarctic nations in the late 20th century. And they found that it's melting faster than they thought.

Most of the ice loss charted stems from rapid melting in West Antarctica, and especially its Pine Island and Thwaites Glaciers.

Antarctica holds enough ice to increase sea levels 58 meters, the researchers said.

Antarctica is not the only contributor to sea-level rise.

"I think we should be anxious".

"The fate of Antarctica, the fate of Greenland, is the fate of Miami", she said. "We will not necessarily see exclusively rapid retreat, " said Christianson, noting that as glaciers like Pine Island retreat backwards down a submarine, downhill slope, they will sometimes encounter bumps that slow down their movement.

Andrew Shepherd of the University of Leeds, who leads the Ice sheet Mass Balance Inter-comparison Exercise (Imbie), said it had always been suspecting changes in Earth's climate would affect the polar ice sheets. "When we look into the ocean we find that it's too warm and the ice sheet can't withstand the temperatures that are surrounding it in the sea", he says.

Whether Antarctic mass loss keeps worsening depends on choices made today, argues DeConto, who co-authored a separate paper in this week's Nature outlining two different visions for Antarctica's future in the year 2070.

Even more grim, a half-century of high emissions by this point would have locked in more than 10 metres (33 ft) of future sea level rise in coming millennia - and could potentially lead to more than 50 metres of sea level rise over the next 10,000 years. "Put simply if we can not collectively tackle climate change, then it's unlikely we will maintain Antarctica as a place for peace, nature and science".

Related:

Comments

Latest news

Trump declares North Korea 'no longer a nuclear threat'
He told reporters that if the USA concludes they no longer are, the freeze "will no longer be in effect". Pompeo said Trump would resume the military drills if North Korea stops negotiating in good faith.

Tactics Kim Jong-Un may use in US-North Korea summit
Past nuclear deals have crumbled over North Korea's reluctance to open its doors to outsiders. It's Kim's pursuit of nuclear weapons that gives his meeting with Trump such high stakes.

John Boyega has a message for online trolls harassing his co-stars
This nearly feels like a direction similar to what Ridley Scott did with Prometheus and Alien: Covenant (for better or worse). The Star Wars fandom has been making waves in the news lately, and not due to their Han Solo-related takes.

Tyson Fury beats Sefer Seferi in comeback fight
Just boxing again was an achievement for Fury, whose life span out of control after ending Klitschko's nine-and-half year reign. But Fury rediscovered his passion for boxing and claimed to have lost eight stones (112 pounds) ahead of facing Seferi.

Five Labour frontbenchers quit over Brexit vote
It also seeks to hand the negotiations over to parliament after February 15 2019 if a deal has not been agreed by that time. That has potentially seismic consequences for the protracted and increasingly messy split from Brussels.

Other news