Warm water quickens melting of Antarctic ice

WASHINGTON — Antarctica’s massive ice shelves are shrinking because they are being eaten away from below by warm water, a new study finds. That suggests that future sea levels could rise faster than many scientists have been predicting.

The western chunk of Antarctica is losing 23 feet of its floating ice sheet each year. Until now, scientists weren’t exactly sure how it was happening and whether or how man-made global warming might be a factor. The answer, according to a study published Wednesday in the journal Nature, is that climate change plays an indirect role — but one that has larger repercussions than if Antarctic ice were merely melting from warmer air.

Hamish Pritchard, a glaciologist at the British Antarctic Survey, said research using an ice-gazing NASA satellite showed that warmer air alone couldn’t explain what was happening to Antarctica. A more detailed examination found a chain of events that explained the shrinking ice shelves.

Twenty ice shelves showed signs that they were melting from warm water below. Changes in wind currents pushed that relatively warmer water closer to and beneath the floating ice shelves. The wind change is likely caused by a combination of factors, including natural weather variation, the ozone hole and man-made greenhouse gases, Pritchard said.

As the floating ice shelves melt and thin, that in turn triggers snow and ice on land glaciers to slide down to the floating shelves and eventually into the sea, causing sea level rise, Pritchard said. Thicker floating ice shelves usually keep much of the land snow and ice from shedding to sea, but that’s not happening now.

That whole process causes larger and faster sea level rise than simply warmer air melting snow on land-locked glaciers, Pritchard said.

“It means the ice sheets are highly sensitive to relatively subtle changes in climate through the effects of the wind,” he said.

What’s happening in Antarctica “may have already triggered a period of unstable glacier retreat,” the study concludes. If the entire Western Antarctic Ice Sheet were to melt — something that would take many decades if not centuries — scientists have estimated it would lift global sea levels by about 16 feet.

NASA chief scientist Waleed Abdalati, an expert in Earth’s ice systems who wasn’t involved in the research, said Pritchard’s study “makes an important advance” and provides key information about how Antarctica will contribute to global sea level rise.

Another outside expert, Ted Scambos of the National Snow and Ice Data Center, said the paper will change the way scientists think about melt in Antarctica. Seeing more warm water encircling the continent, he worries that with “a further push from the wind” newer areas could start shrinking.

Talk to us

> Give us your news tips.

> Send us a letter to the editor.

> More Herald contact information.

More in Local News

A firefighter stands in silence before a panel bearing the names of L. John Regelbrugge and Kris Regelbrugge during the ten-year remembrance of the Oso landslide on Friday, March 22, 2024, at the Oso Landslide Memorial in Oso, Washington. (Ryan Berry / The Herald)
‘Flood of emotions’ as Oso Landslide Memorial opens on 10th anniversary

Friends, family and first responders held a moment of silence at 10:37 a.m. at the new 2-acre memorial off Highway 530.

Julie Petersen poses for a photo with images of her sister Christina Jefferds and Jefferds’ grand daughter Sanoah Violet Huestis next to a memorial for Sanoah at her home on March 20, 2024 in Arlington, Washington. Peterson wears her sister’s favorite color and one of her bangles. (Annie Barker / The Herald)
‘It just all came down’: An oral history of the Oso mudslide

Ten years later, The Daily Herald spoke with dozens of people — first responders, family, survivors — touched by the deadliest slide in U.S. history.

Victims of the Oso mudslide on March 22, 2014. (Courtesy photos)
Remembering the 43 lives lost in the Oso mudslide

The slide wiped out a neighborhood along Highway 530 in 2014. “Even though you feel like you’re alone in your grief, you’re really not.”

Director Lucia Schmit, right, and Deputy Director Dara Salmon inside the Snohomish County Department of Emergency Management on Friday, March 8, 2024, in Everett, Washington. (Ryan Berry / The Herald)
How Oso slide changed local emergency response ‘on virtually every level’

“In a decade, we have just really, really advanced,” through hard-earned lessons applied to the pandemic, floods and opioids.

Ron and Gail Thompson at their home on Monday, March 4, 2024 in Oso, Washington. (Olivia Vanni / The Herald)
In shadow of scarred Oso hillside, mudslide’s wounds still feel fresh

Locals reflected on living with grief and finding meaning in the wake of a catastrophe “nothing like you can ever imagine” in 2014.

Everett mall renderings from Brixton Capital. (Photo provided by the City of Everett)
Topgolf at the Everett Mall? Mayor’s hint still unconfirmed

After Cassie Franklin’s annual address, rumors circled about what “top” entertainment tenant could be landing at Everett Mall.

Everett
Everett man sentenced to 3 years of probation for mutilating animals

In 2022, neighbors reported Blayne Perez, 35, was shooting and torturing wildlife in north Everett.

Dorothy Crossman rides up on her bike to turn in her ballot  on Tuesday, Aug. 1, 2023 in Everett, Washington. (Olivia Vanni / The Herald)
Everett leaders plan to ask voters for property tax increase

City officials will spend weeks hammering out details of a ballot measure, as Everett faces a $12.6 million deficit.

Starbucks employee Zach Gabelein outside of the Mill Creek location where he works on Friday, Feb. 23, 2024 in Mill Creek, Washington. (Olivia Vanni / The Herald)
Mill Creek Starbucks votes 21-1 to form union

“We obviously are kind of on the high of that win,” store bargaining delegate Zach Gabelein said.

Lynnwood police respond to a collision on highway 99 at 176 street SW. (Photo provided by Lynnwood Police)
Police: Teen in stolen car flees cops, causes crash in Lynnwood

The crash blocked traffic for over an hour at 176th Street SW. The boy, 16, was arrested on felony warrants.

The view of Mountain Loop Mine out the window of a second floor classroom at Fairmount Elementary on Wednesday, Jan. 10, 2024 in Everett, Washington. (Olivia Vanni / The Herald)
County: Everett mining yard violated order to halt work next to school

At least 10 reports accused OMA Construction of violating a stop-work order next to Fairmount Elementary. A judge will hear the case.

Imagine Children's Museum's incoming CEO, Elizabeth "Elee" Wood. (Photo provided by Imagine Children's Museum)
Imagine Children’s Museum in Everett to welcome new CEO

Nancy Johnson, who has led Imagine Children’s Museum in Everett for 25 years, will retire in June.

Support local journalism

If you value local news, make a gift now to support the trusted journalism you get in The Daily Herald. Donations processed in this system are not tax deductible.