The world’s two gigantic ice sheets are in greater peril from global warming than previously thought, a study published May 20 says.
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Since taking office, President Trump has abandoned efforts to reduce global warming. It could “take a generation or more to repair the damage.”
Huge expanses of ice are melting alarmingly fast, raising new concerns about “catastrophic consequences for humanity,” a study published May 20 says.
The study focuses on two masses of ice currently sitting on land: The Antarctic and Greenland ice sheets. As temperatures rise, that ice is melting, flowing into the ocean and making sea levels rise.
While change in sea level rise is often measured in centimeters or inches, the ice melt potential of these sheets could raise sea levels dozens of feet.
It’s happening even faster than expected, authors warn in the study published in the journal Communications Earth and Environment.
“Recent satellite-based observations of ice sheet mass loss have been a huge wake-up call for the whole scientific and policy community working on sea-level rise and its impacts,” said study co-author Jonathan Bamber, of the University of Bristol in the UK.
What is an ice sheet?
An ice sheet is a mass of glacial land ice extending more than 20,000 square miles. Ice sheets once covered much of the Northern Hemisphere during the ice age. Now, Earth has just two ice sheets: one covers most of Greenland, the largest island in the world, and the other spans across the Antarctic continent, according to the National Snow and Ice Data Center.
Together, the Antarctic and Greenland Ice Sheets contain more than 99% of the land ice and over 68% of the fresh water on Earth.
Sea levels are rising
Ice loss in Greenland and Antarctica is already influencing ocean waters and causing sea levels around the globe to rise, the NSIDC said. If global greenhouse gas emissions continue at their current rate, Earth’s ice sheets are vulnerable to even more massive rapid ice loss that could substantially raise sea levels.
According to the new study, the mass of ice lost from these ice sheets has quadrupled since the 1990s and they are currently losing around 370 billion metric tons of ice per year.
Recovery could take thousands of years
Even if the Earth returns to its preindustrial temperature, it will still take hundreds to perhaps thousands of years for the ice sheets to recover. If too much ice is lost, parts of these ice sheets may not recover until the Earth enters the next ice age, the study suggests.
Study co-author Rob DeConto, from the University of Massachusetts Amherst, said, “In other words, land lost to sea level rise from melting ice sheets will be lost for a very, very long time. That’s why it is so critical to limit warming in the first place.”
How hot is too hot?
The research suggests global leaders should aim for 1 degree C of warming (as compared to the Earth’s temperature over a century ago) to avoid significant losses from the ice sheets and prevent a further acceleration in sea-level rise.
That’s a lofty goal, considering the 1.5 degree C threshold has long been discussed as a difficult but achievable goal. (Hope has been fleeting about that goal as last year crossed that threshold).
“There is a growing body of evidence that 1.5 degrees is too high for the ice sheets in Greenland and Antarctica,” study lead author Chris Stokes, from the Department of Geography at Durham University in the UK, said in a statement. “We’ve known for a long time that some sea-level rise is inevitable over the next few decades to centuries, but recent observations of ice sheet loss are alarming, even under current climate conditions.”