The Antarctic ice shelf is at the mercy of climate change. A satellite analysis on Wednesday showed that previous estimates of losses from the world’s largest ice sheet over the past 25 years were significantly off the mark. This was due to the fact that Antarctica’s coastal glaciers are losing icebergs at a faster rate. This is faster than nature can replenish the crumbling ice.
Researchers at NASA’s Jet Propulsion Laboratory (JPL) near Los Angeles led a study. This study was the first of its kind and was published in the journal Nature. The study raises new concerns about how quickly climate change is weakening Antarctica’s floating ice shelves. It is also accelerating the rise in global sea levels.
The key finding of the study was that the net loss of Antarctic ice from coastal glacier chunks “calving” off into the ocean is nearly as great as the net amount of ice that scientists already knew was being lost. This is due to the thinning caused by the melting of ice shelves from below due to warming seas. This was the most important finding of the study.
The investigation found that thinning and calving have taken away a total of 12 trillion tons of ice. That is, from Antarctica’s ice shelves since 1997. This is double the amount that was previously estimated.
According to JPL scientist Chad Greene, the principal author of the research, the net loss of the continent’s ice sheet through calving alone in the previous quarter-century spans approximately 37,000 sq km (14,300 sq miles). This is an area that is almost the size of Switzerland.
Antarctic ice shelf is at the mercy of climate change
In a release made by NASA on the findings, Greene stated that “Antarctica is collapsing at its borders.” “And when ice shelves decrease and weaken, the continent’s vast glaciers tend to accelerate. This enhances the pace of global sea level rise.” “And when ice shelves dwindle and weaken.”
The repercussions can be quite severe. According to him, 88% of the sea level potential of all the ice in the world is located in Antarctica.
It takes thousands of years for ice shelves, which are permanent floating sheets of frozen freshwater tied to land, to form. Ice shelves operate as buttresses, preventing glaciers from simply sliding off the ground. This is also into the ocean, which would otherwise cause the sea level to rise.
When ice shelves are in a stable state, the natural process of calving and regrowing throughout time helps to maintain a size that is relatively constant.
Warming waters have, however, damaged the shelves from the bottom in recent decades. This phenomenon was previously observed by satellite altimeters monitoring the changing height of the ice. This showed losses of an average of 149 million tons per year from 2002 to 2020, according to NASA.
The team led by Greene synthesized satellite images from visible, thermal-infrared, and radar wavelengths to monitor glacier movement. This is calving more accurately than ever before along over 30,000 miles (50,000 km) of Antarctic coastline. This allowed them to go back to 1997 and cover more ground.
Natural ice shelf replenishment
The calculated losses from calving exceeded the natural ice shelf replenishment by such a large amount. So, experts concluded that it is highly unlikely that Antarctica will be able to return to pre-2000 glacier levels. That is before the end of the century.
The pace of increased glacial calving, which is similar to the rate at which ice is thinned, was most prominent in West Antarctica. This is a region that has been hit harder by rising ocean currents. But even in the region of East Antarctica, which was thought to have ice shelves that were less susceptible to melting for a long time, “we’re seeing more losses than gains,” Greene said.
The collapse and breakup of the enormous Conger-Glenzer ice shelf in March was one of the East Antarctic calving events. That is, that took the globe by surprise. Greene says that this event could be a sign of a bigger weakening to come.
The Way Forward
The study’s lead author, Eric Wolff, a research professor at the University of Cambridge and a member of the Royal Society, highlighted the study’s investigation of how the East Antarctic ice sheet behaved during warm periods in the past as well as forecasts for what may happen in the future.
“The good news is that if we stay to the 2 degrees of global warming that the Paris accord pledges, the sea level rise attributable to the East Antarctic ice sheet should be low,” Wolff stated in a commentary on the JPL paper. This was in response to the finding that the melting of the East Antarctic ice sheet will cause a small increase in the world’s average sea level.
However, if action is not taken to reduce emissions of greenhouse gases, this may result in “several meters” of further sea level rise over the next few centuries, as he said.
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