ANTARCTICA: 90% of the freshwater on earth is found in Antarctica, where it is encased in vast ice sheets. However, climate change is threatening the stability of much of this ice.
Two studies published this week in the journal Nature examined how climate change is affecting Antarctica’s ice sheets and illustrated the gloomy probable future of sea level rise.
The first study looks at how the melting of Antarctica’s two ice sheets, which act as protective barriers, is affecting their ice shelves.
Ice sheets cover the land, and ice shelves extend out into the sea.
Lead author Chad Greene, a postdoctoral research associate at NASA’s Jet Propulsion Laboratory, said that ice shelves are enormous, hundreds or even thousands of metres thick slabs of ice, and some of them are as big as France.
“This is because ice shelves are in hydrostatic equilibrium and float on top of the ocean, there is no direct effect on sea level when an iceberg breaks off. But every time an ice shelf calves, it shrinks and loses strength a little bit.”
In a typical calving cycle, ice shelves can replenish the ice that has been lost. However, the calving process has been sped up because of climate change, which weakens the ice shelves from below in warming water and makes it more difficult for the shelves to replenish.
Greene and his colleagues used satellite data to create a series of high-resolution images of Antarctica’s coastline over the past 25 years to understand what this would imply for sea-level rise.
“What we discovered is that the edges of Antarctica’s ice shelves have been eroding,” Greene said. Overall, they found that Antarctica’s ice shelves had shrunk by more than 14,280 square miles (37,000 square kilometres) since 1997 (Greene remarked that this is roughly the size of Switzerland).
Thus, over the past 25 years, the ice shelves of the continent have lost nearly 12 million metric tonnes, roughly double the amount previously predicted.
The stability of the continent’s ice sheets over the long term may suffer as a result of all this crumbling.
Antarctica crumbling faster than ever
According to Greene, the ice shelves have been thinning and deteriorating over the past 25 years, which has caused Antarctica’s enormous glaciers to advance faster and contribute to sea level rise.
The Thwaites and Pine Island glaciers in West Antarctica have experienced the worst effects, and neither one appears to be slowing down anytime soon. The Thwaites glacier, sometimes known as the “doomsday glacier,” is in dire need of help.
Even once thought to be stable ice sheets are now displaying symptoms of stress. The East Antarctic ice sheet, the larger of the two ice sheets on the continent and the largest source of freshwater on Earth, is the subject of second research published this week that examines its possible future.
Due to less exposure to increasing ocean waters, this ice sheet has historically been thought of as more protected than the western ice sheet, which contains the Thwaites and Pine Island glaciers.
However, if the East Antarctic ice sheet is ever in danger, it could have severe consequences for the planet because it contains enough water to cause sea levels to rise by more than 170 feet (52 meters).
Chris Stokes, the study’s lead author and a professor of geography at Durham and his co-authors reviewed prior research on how the East Antarctic ice sheet responded to past warm periods and current levels of change, adding in “a bit of new number-crunching based on computer simulations that predict how much this giant ice sheet might contribute to future sea-level rise,” he said, to get a better sense of what the ice sheet’s future might entail.
There is some good news in this study, according to the scientists, who predict that the ice sheet will likely remain stable in the short term and prevent long-term collapse by limiting warming to 2 degrees Celsius by 2100.
However, the report also warns that the East Antarctic ice sheet is already displaying symptoms of stress brought on by climate change and that there is a limited amount of time left to take action.
The East Antarctic ice sheet could cause sea levels to increase by up to 3 to 10 feet (1 to 2 metres) by 2300 if the world continues to warm beyond the limits of the Paris Agreement, according to the study.
“The main finding from our research is that, if the Paris Climate Agreement can be met, we can probably prevent East Antarctica from significantly contributing to sea level rise, according to Stokes. Therefore, I believe that despite all of the gloomy predictions we hear, our work at least raises the possibility that we may have a little window of opportunity to preserve this ice sheet over the coming decades. The fate of the greatest ice sheet on Earth is largely in our control, as we conclude in the research.”
The message of these two publications is obvious: significant warming mitigation is essential to keeping everyone above water.
Also Read: Historic Climate Change Report – IPCC Warns Of No End To Warming
