We now know that the ice shelves of the Northern Hemisphere are shrinking, and that glaciers in the Southern Hemisphere are melting faster than previously thought.
But scientists have long suspected that the Southern hemisphere’s glaciers were a bit more stable and more likely to melt.
The new research by researchers from the University of Wisconsin-Madison and the University at Buffalo, who study the evolution of ice sheets, shows that this may not be the case.
“There is a lot of uncertainty surrounding the glaciers’ role in the melting of the Southern ice sheets,” said lead author Michael S. J. Anderson, a glaciologist at the University’s Lamont-Doherty Earth Observatory (LDO).
“Our study shows that the glaciers are in a stable state.”
The study was published in the journal Nature Climate Change.
“Our research shows that in the last decades of the Holocene, there was a bit of a lull in ice sheet growth,” said co-author Andrew M. D. Stott, an associate professor in the LDO’s Department of Earth and Planetary Sciences.
“That lull was followed by a steady increase in ice growth in the past century.
This research suggests that, while the Southern [glaciers] are still expanding, they are less likely to contribute significantly to the overall rate of ice loss.”
The research involved analyzing more than 7,000 satellite-based images of the ice sheets of Greenland and Antarctica to determine how much ice there is in each area.
The images show that the Greenland ice sheet has more than doubled in size in the century since satellites began collecting data there, and the glaciers in Antarctica have also been expanding at a much slower rate.
“It’s a nice finding,” said D.C. Rummel, a professor of earth and planetary sciences at the LDE who was not involved in the research.
“This research makes a strong case that glaciers have been growing at a faster rate than previously realized.”
This was a surprising result, given that the amount of ice in Antarctica was increasing by around a factor of two a century ago, Anderson said.
“But that wasn’t a surprise to us because we’ve known for decades that the Antarctic ice sheet is growing.
But this is the first time that we’ve been able to say that it’s a trend that’s actually slowing down.”
The researchers found that in a relatively stable climate, glaciers can hold about as much ice as the planet can support, but that they tend to lose more ice when the climate warms up.
“In a warmer climate, they’re more likely,” Stott said.
In a warming climate, “they’re more vulnerable to melting.”
Anderson and Stott say that, in their research, the glaciers appear to be shrinking at about half the rate that they were previously thought, which means that the region is losing more ice in the process.
In the southern hemisphere, they found that there was more ice lost per decade than there was growth, meaning that, overall, the rate of loss was about half what was previously thought and the rate was accelerating.
“What this study shows is that the loss is accelerating, not decreasing,” Anderson said, adding that it also makes it clear that “there is a need to continue monitoring the glacier and to look for other signs of the rapid growth in glaciers in both the Southern and Northern hemispheres.”
The scientists are now looking at whether they can figure out what the causes of this trend are.
The researchers also found that the rate at which the glaciers were losing ice was slowing down as the climate warmed.
“We’re seeing that glaciers are shrinking because of climate change,” Anderson explained.
“As they warm, the water in their glaciers is losing the ice in it, and so that ice is getting trapped.
And the problem is that that’s trapping a lot more ice, so the glaciers lose more.
The more ice they lose, the more vulnerable they become to melting.
So that’s one possible explanation for the slower rate of glacier loss in the Northern hemisphere.
“The answer to that question will tell us how we can better protect our coastal communities, which is the most vulnerable region of the world, from the consequences of climate warming,” said Stott. “
“The Southern Ice Shelf has a really significant impact on global warming, and it’s only going to get worse as the warming continues.” “
The answer to that question will tell us how we can better protect our coastal communities, which is the most vulnerable region of the world, from the consequences of climate warming,” said Stott.
“The Southern Ice Shelf has a really significant impact on global warming, and it’s only going to get worse as the warming continues.”
[NASA/NOAA/SARASOTA/University of Wisconsin] This story was produced by Climate Central using data from the National Snow and Ice Data Center (NSIDC), the Global Climate Data Center, and NASA’s Goddard Institute for Space Studies.
The views expressed in this article are the authors own and do not necessarily reflect Al Jazeera’s editorial stance.