Share

Loss of West Antarctic Glaciers 'Unstoppable,' Could Raise Seas by 4 Feet

By Terrell Johnson
Published: May 13, 2014

A section of the West Antarctica ice sheet is melting so quickly that nothing can stop the glaciers in the area from melting completely into the surrounding ocean, a group of scientists from NASA and the University of California-Irvine reported in a study released today.

From observing the Amundsen Sea sector of West Antarctica for the past four decades, the scientists have concluded that the glaciers there "have passed the point of no return," said Eric Rignot, a glaciologist at U.C. Irvine and NASA's Jet Propulsion Laboratory, and lead author of the study, published in the scientific journal Geophysical Research Letters.

The study, announced in a NASA press conference Monday, noted that the glaciers and ice shelves along the Amundsen Sea (shown in the video below) already release roughly the same amount released by the entire Greenland ice sheet into the ocean every year, and contain enough ice to raise the world's sea level by about 4 feet.

 

The glaciers are melting much faster than scientists had previously estimated, Rignot said, a development that means forecasts for sea level rise worldwide – like those released by the Intergovernmental Panel on Climate Change earlier this year – will have to be revised upward in a significant way.

"This sector will be a major contributor to sea level rise in the decades and centuries to come," Rignot said in a NASA press release, adding that "a conservative estimate is it could take several centuries for all of the ice to flow into the sea."

To reach their conclusions, the scientists looked at three lines of evidence: the rate at which the glaciers are flowing into the ocean today, how much of each glacier currently floats on top of seawater, and the terrain of the land underneath each – how it is sloped and how much lies below sea level, which indicate how quickly a glacier moving over it can be expected to push into the ocean.

The study looked closely at what are known as "grounding lines," the point where the ice of a glacier loses contact with the land and enters the sea. Here's how NASA describes the interaction:

"Just as a grounded boat can float again on shallow water if it is made lighter, a glacier can float over an area where it used to be grounded if it becomes lighter, which it does by melting or by the thinning effects of the glacier stretching out," the release notes.

(MORE: Antarctica Was Once As Warm As California, Florida: Study)

"The Antarctic glaciers studied by Rignot's group have thinned so much they are now floating above places where they used to sit solidly on land, which means their grounding lines are retreating inland."

The process of glacial melting reinforces and amplifies itself, the study notes. "As glaciers flow faster, they stretch out and thin, which reduces their weight and lifts them farther off the bedrock. As the grounding line retreats and more of the glacier becomes waterborne, there's less resistance underneath, so the flow accelerates," the NASA release points out.

So why is this happening, and what does it mean for the West Antarctica ice sheet and the world's coastal cities? Earth's warming climate – specifically, the heat that is being stored in the oceans as the world gets warmer – is partly to blame, the scientists say.

"The collapse of this sector of West Antarctica appears to be unstoppable," he said. "The fact that the retreat is happening simultaneously over a large sector suggests it was triggered by a common cause, such as an increase in the amount of ocean heat beneath the floating sections of the glaciers. At this point, the end of this sector appears to be inevitable."

Read more at NASA, or read the full scientific study at Geophysical Research Letters.

 

West Antarctica Glacier Melt 'Unstoppable'

West Antarctica Glacier Melt 'Unstoppable'

An aerial view of Antarctica's Thwaites Glacier. NASA scientists said Monday that the rapidly melting glaciers in the Amundsen Sea sector of West Antarctica 'have passed the point of no return.' (NASA)

  • West Antarctica Glacier Melt 'Unstoppable'
  • West Antarctica Glacier Melt 'Unstoppable'
  • West Antarctica Glacier Melt 'Unstoppable'
  • West Antarctica Glacier Melt 'Unstoppable'

Featured Blogs

U.S. Wildfires 2015: Are The Worst Yet To Come?

By Dr. Jeff Masters
September 2, 2015

Thus far, 2015 has been one of the worst U.S. wildland fire seasons since modern records began, largely due to massive fires in Alaska. As fall approaches, the risk of major fire continues across the western states, with the role of climate change under increased scrutiny. Meanwhile, the Northern Hemisphere tropics are beginning to settle down for a spell after a hyperactive August.

UPDATE: Crazy Summer in Hawaii: Record Rainfall, Record Heat, and Snow!

By Christopher C. Burt
August 26, 2015

Although much media attention weather-wise (at least recently) for Hawaii has been about tropical storms an even more interesting story has been the record wet August in Honolulu and Lihue and the hottest summer and hottest single month (August) on record for many Hawaiian cities. Despite a record warm July, accumulating snow managed to dust the summit of Mauna Kea on the Big Island. Here are some details about the above events.

Not a tropical cyclone?

By Stu Ostro
August 15, 2015

PWS Service Interruption Update

By Shaun Tanner
June 16, 2015

The development team here at Weather Underground has been hard at work producing a new homepage! Please take a look at the sneak peek and tell us what you think!

2013-14 - An Interesting Winter From A to Z

By Tom Niziol
May 15, 2014

It was a very interesting winter across a good part of the nation from the Rockies through the Plains to the Northeast. Let's break down the most significant winter storms on a month by month basis.

What the 5th IPCC Assessment Doesn't Include

By Angela Fritz
September 27, 2013

Melting permafrost has the potential to release an additional 1.5 trillion tons of carbon into the atmosphere, and could increase our global average temperature by 1.5°F in addition to our day-to-day human emissions. However, this effect is not included in the IPCC report issued Friday morning, which means the estimates of how Earth's climate will change are likely on the conservative side.