Quantcast

Study Reveals Dangerous Antarctic Feedback Loop

A new study of the melting patterns of glaciers in Antarctica provides real-world evidence for one of the more troubling model-based climate change predictions, The Washington Post reported Monday.

The study, published April 18 in Science Advances, found that fresh water melting off of glaciers in some regions of Antarctica caused a layer of cold, fresh water to float above warmer, saltier water, both slowing ocean circulation and melting lower parts of the ice sheets.


Alessandro Silvano, the study's lead author and a Ph.D. student with the University of Tasmania's Institute for Marine and Antarctic Studies (IMAS), explained the mechanism in everyday terms.

"This process is similar to what happens when you put oil and water in a container, with the oil floating on top because it's lighter and less dense," Silvano said in an IMAS press release.

But unlike mixing oil and water, this mechanism has global implications as the warmer, denser water leads to more melting.

"We found that in this way increased glacial meltwater can cause a positive feedback, driving further melt of ice shelves and hence an increase in sea level rise," Silvano said.

The process also slows the circulation of ocean currents because it prevents the sinking of dense, cold water called "Dense Shelf Water." The study found that the formation of Dense Shelf Water had stopped off of East Antarctica's Sabrina Coast and in the Amundsen Sea in West Antarctica.

"The cold glacial meltwaters flowing from the Antarctic cause a slowing of the currents which enable the ocean to draw down carbon dioxide and heat from the atmosphere. In combination, the two processes we identified feed off each other to further accelerate climate change," Silvano said.

As The Washington Post pointed out, Silvano's research backs up a study co-authored by early climate change alarm-sounder Dr. James Hansen in 2016, which used computer models to predict that melting ice in Antarctica and Greenland would warm the oceans below the surface and increase the rate of melting, increasing storms and leading to sea level rise of "several meters over a timescale of 50 to 150 years," according to the abstract.

"Our study shows for the first time actual evidence of this mechanism. Our study shows that it is already happening," Silvano told The Washington Post.

Hansen himself also commented, saying "this study provides a nice small-scale example of processes that we talk about in our paper," the Post reported.

"On the large-scale issue, it is too early to say how these feedback processes will play out, based on empirical evidence," Hansen told the Post by email. "If we stay on business-as-usual [greenhouse gas] emissions rates, so that global warming continues to increase, I expect that the freshwater injection rate will increase (mainly via ice faster ice shelf breakup and underwater melt) and sea ice area will increase. This experiment will be playing out over the next years and decades."

This study comes days after reports that the Atlantic Meridional Overturning Circulation (AMOC), which brings warm water from the tropics and moves cool water south, is weaker than at any point in the last thousand years.

"Of those two key areas of deep water formation, the northern Atlantic one has been widely considered more vulnerable to global warming," Stefan Rahmstorf, a scientist at the Potsdam Institute for Climate Impact Research, told The Washington Post. "It is therefore of some concern that we now see increasing signs that the deep water formation around Antarctica is already being affected."

Because the study's authors do not have measurements for Dense Shelf Water formation in the regions studied going back far enough, they cannot be certain that the current changes are due to climate change, though the melting of fresh water from glaciers would still impact the process going forward, The Washington Post reported.

Show Comments ()

EcoWatch Daily Newsletter

A metal fence marked with the U.S. Border Patrol sign prevents people to get close to the barbed/concertina wire covering the U.S./Mexico border fence, in Nogales, Arizona, on Feb. 9. ARIANA DREHSLER / AFP / Getty Images

President Donald Trump issued the first veto of his presidency Friday, overturning Congress' vote to block his national emergency declaration to fund a border wall that environmental advocates say would put 93 endangered species at risk. However, the president's decision came the same day as an in-depth report from UPI revealing how razor wire placed at the border in the last four months already threatens wildlife.

Read More Show Less
Guillermo Murcia / Moment / Getty Images

By Ansley Hill

Vitamin D is an essential nutrient that your body needs for many vital processes, including building and maintaining strong bones.

Read More Show Less
Sponsored
D'Bone Collector Museum head Darrell Blatchley shows plastic found inside the stomach of a Cuvier's beaked whale in the Philippines this weekend. - / AFP / Getty Images

Yet another whale has died after ingesting plastic bags. A young male Cuvier's beaked whale was found washed up in Mabini, Compostela Valley in the Philippines Friday, CNN reported. When scientists from the D' Bone Collector Museum in Davao investigated the dead whale, they found it had died of "dehydration and starvation" after swallowing plastic bags―40 kilograms (approximately 88 pounds) worth of them!

Read More Show Less
Pexels

By Jeff Turrentine

"Be careful what you wish for; you just might get it." This is something that everybody has to learn at some point. Lately, the lesson has hit home for a group of American automakers.

Read More Show Less
Art direction: Georgie Johnson. Illustrations: Freya Morgan

By Joe Sandler Clarke

"Don't expect us to continue buying European products," Malaysia's former plantations minister Mah Siew Keong told reporters in January last year. His comments came just after he had accused the EU of "practising a form of crop apartheid."

A few months later Luhut Pandjaitan, an Indonesian government minister close to President Joko 'Jokowi' Widodo, warned his country would retaliate if it was "cornered" by the EU.

Read More Show Less
Sponsored
Torres and his parents walk along the Rio Grande. Luis Torres / Earthjustice

By Luis Torres

For some people who live along the U.S.-Mexico border, President Trump's attempt to declare a national emergency and extend the border wall is worse than a wasteful, unconstitutional stunt. It's an attack on their way of life that threatens to desecrate their loved ones' graves.

Read More Show Less
Flooding at the Platte River south of Fremont, Nebraska. Gov. Pete Ricketts

Flooding caused by last week's bomb cyclone storm has broken records in 17 places across the state of Nebraska, CNN reported Sunday. Around nine million people in 14 states along the Mississippi and Missouri Rivers were under a flood watch, CNN meteorologist Karen Maginnis said.

Read More Show Less
A car destroyed by Cyclone Idai in Beira, Mozambique. ADRIEN BARBIER / AFP / Getty Images

At least 150 people have died in a cyclone that devastated parts of Mozambique, Zimbabwe and Malawi over the weekend, The Associated Press reported Sunday. Cyclone Idai has affected more than 1.5 million people since it hit Mozambique's port city of Beira late Thursday, then traveled west to Zimbabwe and Malawi. Hundreds are still missing and tens of thousands are without access to roads or telephones.

"I think this is the biggest natural disaster Mozambique has ever faced. Everything is destroyed. Our priority now is to save human lives," Mozambique's Environment Minister Celso Correia said, as AFP reported.

Read More Show Less