Current:Home > Contact-usAre Antarctica’s Ice Sheets Near a Climate Tipping Point?-LoTradeCoin
Are Antarctica’s Ice Sheets Near a Climate Tipping Point?
View Date:2024-12-23 16:47:17
Stay informed about the latest climate, energy and environmental justice news by email. Sign up for the ICN newsletter.
The world needs to eliminate nearly all carbon dioxide emissions from coal burning by 2050 to avoid pushing Antarctica’s ice sheets past a tipping point that could cause a major surge in sea level rise, new research shows.
If CO2 emissions from fossil fuels continue at their present pace, many Pacific islands and millions of people along low-lying shores like the U.S. Gulf Coast and the Bay of Bengal could be swamped by 1.3 meters (more than 4 feet) of sea level rise before the end of this century, an international team of scientists found in a new study published today in the journal Environmental Research Letters.
The researchers said their work supports evidence that global warming of more than 1.9 degrees Celsius could push parts of the West Antarctic Ice Sheet past a melting threshold that would rapidly increase the pace of sea level rise.
“What we are increasingly seeing is that we have been on the conservative side in estimating sea level rise,” said study co-author Carl-Friedrich Schleussner, a climate physicist at Climate Analytics, a climate science and policy institute. “Parts of the West Antarctic Ice Sheet appear to already be in substantial decline. If that continues, it’s not a matter of how much, but how fast sea level will rise.”
Keeping within a strict carbon budget, including steep and rapid reductions of CO2 from fossil fuels, might limit this century’s sea level rise to just half a meter, or 1.6 feet—still a hazard for many low-lying communities, but not as catastrophic elsewhere.
The new estimate of the worst-case scenario is more alarming than the consensus view of the Intergovernmental Panel on Climate Change (IPCC) in its 2014 assessment, but closer to the increases anticipated by more recent research, Schleussner said. That’s largely because the new study incorporates recent science showing the risk of more severe melting of Antarctic ice under future warming, even if the Paris climate agreement is somewhat successful in keeping warming moderately under control.
The study also uses a newer, more sophisticated approach to assessing the various pathways the world could take as governments struggle to keep global warming to less than 2 degrees Celsius above pre-industrial times. Which pathways policy makers follow would influence how much and how fast the planet warms.
What 2 Degrees Could Mean for the Ice Sheets
Key to the new projections is a March 2016 study in the journal Nature suggesting that even the large ice sheets of Antarctica could be susceptible to large-scale collapse at a warming threshold of about 2 degrees Celsius.
At that point, giant ice cliffs at the ocean’s edge could start to crumble from above and below. From the surface, meltwater will pour down into deep cracks and pry the ice apart; from below, tongues of warmer ocean water will free the floating shelves from rocky anchors, speeding the flow of the ice sheets into the sea.
Data from University of Massachusetts-Amherst climate scientist Rob DeConto, lead author of the 2016 Nature study, shows that the Antarctic ice sheets and glaciers get more sensitive to higher levels of warming, Schleussner said. “Antarctica is the main driver of the risk of really high sea level rise, so we really need to understand what’s happening there.”
The West Antarctic Ice Sheet and the Thwaites Glacier appear especially vulnerable to the 1.9 degree Celsius tipping point, said Ted Scambos, a polar ice expert with the National Snow and Ice Data Center. The Thwaites Glacier has accelerated. Other glaciers in the area are getting thinner, and their floating extensions, the ice shelves, are thawing from beneath and losing hold of their fixed anchor points.
“It looks like it (Thwaites Glacier) could express this kind of rapid retreat in the coming few centuries. The physics are certainly plausible,” said Scambos, who was not involved in the new study. Other scientists have found deep gouges on the Antarctic sea floor caused by icebergs during ancient times of temperature change, signs that are consistent with the theory of rapid ice shelf disintegration, he said.
If summer temperatures in that region warm by about 2 degrees Celsius, it would lead to a drastic increase in the amount of water in the snowpack on the surface of the Thwaites Glacier. The water eventually pools in reservoirs that can then take a toll on the ice.
“Those lakes are like sledgehammers. They crack the glacier open,” Scambos said. He said an international effort is planned to explore the Thwaites ice field system from its where it begins all the way out to where it meets the Amundsen Sea.
A Case for Quickly Cutting Emissions
The melting ice cliffs at the edge of the ocean become yet another self-reinforcing climate feedback, said co-author Matthias Mengel, an ice sheet modeler with the Potsdam Institute for Climate Impacts Research.
“What is directly behind the ice cliff is an even higher ice cliff, and it will also break off. If an ice front is too high, it can’t carry its own weight. To us, this new approach was really kind of a bomb. It changed our idea completely about how Antarctica could change in the future,” he said. “This means a big change in the numbers of the amount of sea level rise we could get from Antarctica. It’s a new twist for ice loss, but we also have to wait for results to come in. This is new science, and it’s evolving.”
Right now, the thick coastal ice shelves are still frozen in place to rocks on the sea floor, holding back the land-based ice sheets, but if the ice shelves start to disappear, the scientists expect the ice flow from the interior will accelerate, he said.
The recent research on rapid glacier and ice shelf melting is a game-changer, Schleussner said. The new sea level rise estimates add to the case for quickly cutting carbon emissions to near zero to avoid extreme sea level rise and the harm it would cause to millions of people.
“But if you look at planned coal capacity, especially in the developing countries of South Asia, we are not getting anywhere close to where we need to be to meet the targets of the Paris agreement,” he said. “The value of the study is linking up ambition on climate action, showing how specific actions will affect things like sea level rise.”
veryGood! (763)
Related
- Candidates line up for special elections to replace Virginia senators recently elected to US House
- Passenger says airline lost her dog after it escaped and ran off on the tarmac
- Meta says Chinese, Russian influence operations are among the biggest it's taken down
- Backpage founder faces 2nd trial over what prosecutors say was a scheme to sell ads for sex
- Infowars auction could determine whether Alex Jones is kicked off its platforms
- Dollar General shooting victims identified after racially-motivated attack in Jacksonville
- Joe the Plumber, who questioned Obama's tax plans during 2008 campaign, dead at 49
- 3 U.S. Marines killed in Osprey aircraft crash in Australia
- Barbora Krejcikova calls out 'unprofessional' remarks about her appearance
- As Idalia churns toward Florida, residents urged to wrap up storm preparations
Ranking
- John Krasinski named People's Sexiest Man Alive for 2024
- What are the hurricane categories and what do they mean? Here's a breakdown of the scale and wind speeds
- Killer identified in Massachusetts Lady of the Dunes cold case
- Pregnant Jessie James Decker Gets Candid About Breastfeeding With Implants
- Bill on school bathroom use by transgender students clears Ohio Legislature, heads to governor
- Joe the Plumber, who questioned Obama's tax plans during 2008 campaign, dead at 49
- Son stolen at birth hugs his mother for first time in 42 years after traveling from U.S. to Chile
- Six St. Louis inmates face charges stemming from abduction of jail guard
Recommendation
-
Bev Priestman fired as Canada women’s soccer coach after review of Olympic drone scandal
-
Philadelphia school district offering to pay parents $3,000 a year to take kids to school
-
France’s education minister bans long robes in classrooms. They’re worn mainly by Muslims
-
UNC faculty member killed in campus shooting and a suspect is in custody, police say
-
Mississippi governor intent on income tax cut even if states receive less federal money
-
Peter Navarro says Trump asserted privilege over testimony during Jan. 6 committee investigation
-
Indiana police arrest 2nd man in July shooting at massive block party that killed 1, injured 17
-
Hollywood writers strike impact reaches all the way to Nashville's storied music scene