Nav: Home

Shrinking of Greenland's glaciers began accelerating in 2000, research finds

December 11, 2019

SAN FRANCISCO - Satellite data has given scientists clues about how, when and why Greenland's glaciers are shrinking - and shows a sharp increase in glacial retreat beginning about 2000, according to new research presented this week.

In a presentation at the annual meeting of the American Geophysical Union, scientists released time-lapse satellite images dating back 34 years of about 200 glaciers on the island of Greenland. The images are the first to compare Greenland's glacier retreat - when a glacier shrinks back from the ocean, pulling inland - and the speed at which the glaciers are retreating.

"These glaciers are calving more ice into the ocean than they were in the past," said Michalea King, who presented the research at AGU. King is a graduate student in earth sciences at The Ohio State University. "We're finding this clear correlation where more retreat instigates greater discharge of ice."

To evaluate the glaciers, King analyzed images from the NASA-U.S. Geological Survey's Landsat missions, an ongoing project to monitor the Earth's surface from space. The satellites survey much of the Earth's surface; scientists at AGU also presented on changes to glaciers and ice fields in Alaska and Antarctica.

"One thing we've noticed is that retreat has been a pattern that we've seen across the ice sheets in Greenland," King said. "It's not just limited to one region."

That means the glaciers are not just shrinking in one part of the ice sheet covering Greenland - in the north or south, for example - but that most glaciers across the country have retreated.

The satellite imagery, which, for King's study, dates back to 1985, showed Greenland's glaciers have retreated about 3 miles (5 kilometers) between 1985 and 2018. That data also shows that in 2000, that retreat began accelerating. In 2000, she said, the rate of ice calving - the phenomenon by which chunks of ice break off the glacier and tumble into the ocean - began to increase. In recent years, the data shows that about 50 gigatons more ice per year calves into the ocean than what scientists observed prior to 2000.

That matters for the glacier's size: Prior to 2000, the ice that calved from the glacier was roughly equivalent to the amount of snow that accumulated on the ice sheet - essentially, the mass lost to calving was a wash, because it was replaced by new snowfall.

But after 2000, that equilibrium went out of whack: The glacier is losing ice faster than snow is falling to replace it.

"The ice sheet is out of balance," King said.

And while calving is just one way in which glaciers shrink - meltwater also affects how fast a glacier can flow - it is an important component for a glacier's health, King said.

She said the year 2000 is noteworthy for one reason: In that year, scientists saw glaciers across Greenland begin to retreat more rapidly.

"Their fronts had retreated further inland, which allowed the ice to flow faster, and that brought more ice into the ocean," she said.

King said the triggers for that retreat vary by region, but in southeast Greenland, the retreat was largely caused by warming ocean waters that melted the front of the glaciers.

The satellite images show that, overall, most of the glaciers across Greenland have lost mass, King said.

"There is a very clear relationship between the retreat and increasing ice mass losses from these glaciers during the 1985-through-present record."
-end-
Contact: Michalea King, king.375@osu.edu

Written by: Laura Arenschield, arenschield.2@osu.edu

Ohio State University

Related Ice Sheet Articles:

Greenland ice sheet shows losses in 2019
The Greenland Ice Sheet recorded a new record loss of mass in 2019.
Warming Greenland ice sheet passes point of no return
Nearly 40 years of satellite data from Greenland shows that glaciers on the island have shrunk so much that even if global warming were to stop today, the ice sheet would continue shrinking.
Greenland ice sheet meltwater can flow in winter, too
Liquid meltwater can sometimes flow deep below the Greenland Ice Sheet in winter, not just in the summer, according to CIRES-led work published in the AGU journal Geophysical Research Letters today.
Ice sheet melting: Estimates still uncertain, experts warn
Estimates used by climate scientists to predict the rate at which the world's ice sheets will melt are still uncertain despite advancements in technology, new research shows.
Thousands of meltwater lakes mapped on the east Antarctic ice sheet
The number of meltwater lakes on the surface of the East Antarctic Ice Sheet is more significant than previously thought, according to new research.
Researchers discover ice is sliding toward edges off Greenland Ice Sheet
They found that ice slides over the bedrock much more than previous theories predicted of how ice on the Greenland Ice Sheet moves.
A clearer picture of global ice sheet mass
Fluctuations in the masses of the world's largest ice sheets carry important consequences for future sea level rise, but understanding the complicated interplay of atmospheric conditions, snowfall input and melting processes has never been easy to measure due to the sheer size and remoteness inherent to glacial landscapes.
Researchers discover more than 50 lakes beneath the Greenland Ice Sheet
Researchers have discovered 56 previously uncharted subglacial lakes beneath the Greenland Ice Sheet bringing the total known number of lakes to 60.
Ice-sheet variability during the last ice age from the perspective of marine sediment
By using marine sediment cores from Northwestern Australia, a Japanese team led by National Institute of Polar Research (NIPR) and the University of Tokyo revealed that the global ice sheet during the last ice age had changed in shorter time scale than previously thought.
Novel hypothesis goes underground to predict future of Greenland ice sheet
The Greenland ice sheet melted a little more easily in the past than it does today because of geological changes, and most of Greenland's ice can be saved from melting if warming is controlled, says a team of Penn State researchers.
More Ice Sheet News and Ice Sheet Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: The Power Of Spaces
How do spaces shape the human experience? In what ways do our rooms, homes, and buildings give us meaning and purpose? This hour, TED speakers explore the power of the spaces we make and inhabit. Guests include architect Michael Murphy, musician David Byrne, artist Es Devlin, and architect Siamak Hariri.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at Radiolab.org/donate.     You can read The Transition Integrity Project's report here.