28 Trillion Ton Ice Melt Spells Danger For Sea Level Rise, Climate Change
A total of 28 trillion tons of ice has disappeared from the Earth’s surface since 1994, according to the results of a study that shocked the U.K. researchers who conducted it.
This reportfulfills the worst-case scenariothat was predicted by the Intergovernmental Panel on Climate Change 30 years ago. Scientistsfrom Leeds and Edinburgh universities and University College London predict that by the end of this century, sea level could rise by more than 3 feet.
Researchers studied satellite imageryof the planet’s ice-covered surfaces, including glaciers, mountains and poles, to determine the amount of ice melt triggered by global heatingcaused by rising greenhouse gas emissions.
It’s the first study to examine loss of ice coverage from every region of the planet, says one of the study’s co-authors, professor Andrew Shepherd, director of the Leeds University Centre for Polar Observation and Modeling. His team has previously studied ice loss with a focus on Antarctica and Greenland.
“But when we added everything up together, we saw similar amounts of ice being lost in every corner of the planet, actually,” he says. “And so that multiplied up what we’d been looking up from Antarctica alone, for instance, to a number that was much, much bigger and really quite worrying.”
Shepherd says the total ice melt measures out to about a trillion tons each year — and the Earth’s ice continues to melt. The rate of ice loss has risen by 57% since the 1990s, from 0.8 to 1.2 trillion tons of ice per year, according to the report.
To put that total of 28 trillion tons in perspective, it would cover an area about the size of the U.K.
“If you spread all of that ice on the U.K., for instance, where I live, it would be 100 meters thick, 330 odd feet,” he says. “I mean, that’s a thick layer of ice, and the U.K. is not a small country.”
The study looked at two types of ice on Earth: the ice on the ground and the ice that’s normally floating in the sea. If the ice that is normally above land melts into the sea, it will cause sea level to rise, Shepherd says. Every centimeter of sea level rise that’s about a third of an inch means a million people will be displaced.
Sea level rise often presents a bigger problem for low-lying islands, leading many people to believe they won’t be affected by it, Shepherd says.
“But it’s become increasingly apparent that the bigger threat to our lifestyles and also livelihoods is coastal flooding when we have intense storms which superimpose themself upon the mean sea level,” he says.
Scientists expect sea level to rise by an average of 50 centimeters over the next few decades, which increases the frequency of coastal flooding, Shepherd says. So these coastal flooding events will become much more common than in the past.
“We expect an extra million people to be flooded once per year with every centimeter of sea level rise,” he says.
The ice melting on the surface of the ocean is also concerning because those ice sheets keep Earth cooler, Shepherd says. That ice melt will also speed up the rate of sea level rise.
According to the report, the surface temperature of the planet has risen by 0.85 degrees Celsius since 1880, which has in turn driven up sea and atmospheric temperatures and led to this catastrophic ice loss.
“If you retreat the sea ice, particularly in the Arctic Ocean, but also now in the Southern Ocean, you just bring forward in time the sea level rise that we thought might be 50 or 100 years away,” Shepherd says. “It’s going to happen sooner because the floating ice is melting, too.”
The scientists’ conclusions affirm the IPCC’s worst fears reported in the group’s first assessmentreport 30 years ago, which confirmed that climate change was real and was caused by increasing levels of greenhouse gases from burning fossil fuels.
The report comes in the middle of an unprecedented pandemic and residual economic collapse across the world. Shepherd says the experience of 2020 has taught people that they can adapt their lifestyles, which means similar measures could be taken to slow down climate change.
“We’ve learned through this natural experiment that the world doesn’t end when we change our lifestyles, and we can continue and be prosperous,” he says. “And so it’s been a little bit of a fortunate experiment because people can’t say now that we can’t adapt to climate change.”
Through the current economic downfall, people have also realized that “economies can be rebalanced to deal with emergencies,” Shepherd says.
“We’ve found cash where people believed it didn’t exist, and we could do the same for climate change,” he says. “It’s a simple economic cost. We can’t continue to allow coastal cities to be flooded and people to bear the costs.”
At this point, it’s unrealistic to think we will be able to cool the planet back down, but what we can do is slow down the rate at which the Earth continues to warm, Shepherd says. Hopefully, we can do so at a rate slow enough to allow us to adapt.
“We’re living in a time when ice is melting everywhere on the planet, and now we’ve got 20 or 30 solid years of satellite measurements,” he says. “It’s really impossible for people to deny that that’s happening.”
This article was originally published on WBUR.org.
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