Scientists have found that the huge rise in sea levels due to the melting of the Greenland ice sheet is now inevitable, even if the burning of fossil fuels that is driving the climate crisis were to stop overnight.
The research shows that global warming so far will cause an absolute minimum sea level rise of 27 cm (10.6 inches) from Greenland alone as 110 tn tonnes of ice melt. With continued carbon emissions, the melting of other ice caps, and the thermal expansion of the ocean, a sea level rise of several meters seems likely.
Billions of people live in coastal regions, making flooding from sea level rise one of the biggest long-term impacts of the climate crisis. If Greenland’s record melting year in 2012 becomes a regular occurrence later this century, as is possible, then the ice sheet will produce a “staggering” 78 cm sea level rise, the researchers said. scientists
Previous studies have used computer models of ice sheet behavior to estimate future losses, but the physical processes are complex and this leads to significant uncertainties in the results.
Instead, the study published in the journal Nature Climate Change used satellite measurements of Greenland ice loss and the shape of the ice sheet from 2000 to 2019. This data allowed scientists to calculate how much point global warming has pushed the ice sheet from an equilibrium where snowfall matches ice loss. This made it possible to calculate how much more ice must be lost to regain stability.
“It’s a very conservative minimum,” said Professor Jason Box of the National Geological Survey of Denmark and Greenland (Geus), who led the research. “Realistically, we’ll see that number more than double over the course of this century.”
The 27 cm estimate is a minimum because so far it only takes into account global warming and because it does not include some ways in which glacier ice is lost at the margins of the ice sheet.
The advantage of this study is that it provides a robust estimate of inevitable sea level rise, but the method used does not give a time scale over which the ice will be lost. However, based on scientists’ general understanding of how sheets like Greenland lose ice to the ocean, the researchers said most of the increase would occur relatively soon. In 2021, other scientists warned that a significant portion of the Greenland ice sheet was on the brink of a tipping point.
“The 27cm minimum is the shortfall in sea level rise that we have accumulated so far and it will be paid for, regardless of what we do in the future,” said Dr William Colgan, also from Geus. “Whether it’s 100 or 150 years from now, it will come. And the sea level rise that we’re committed to is growing right now, because of the climate trajectory that we’re on.”
Colgan said, “Yes [2012] becomes a normal year, then the committed loss increases to 78 cm, which is amazing, and the fact that we are already flashing in this range [of ice loss] it’s shocking But the difference between 78cm and 27cm stands out [difference] which can be done through the implementation of the Paris Agreement. There is still a lot of room to minimize the damage.”
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Glaciers in the Himalayas and the Alps are already on track to lose a third and a half of their ice respectively, while some scientists also believe the West Antarctic ice sheet has passed the tipping point that significant losses are inevitable. Warming oceans also expand, raising sea levels.
“There is growing support in the scientific literature for levels of rise of several meters in the next 100 to 200 years,” Colgan said. If climate action were taken quickly, a collapse of the colossal East Antarctic ice sheet, which would lead to a sea level rise of 52 meters if it all melted, could be avoided.
Professor Gail Whiteman, from the University of Exeter, who was not part of the study team, said: “The results of this new study are hard to ignore for all business and policy leaders concerned about future of humanity. It’s bad news for the nearly 600 million people who live in coastal areas around the world. As sea levels rise, they will become increasingly vulnerable and threaten approximately one billion dollars of world wealth”. He said political leaders must quickly increase funding for adaptation and climate damage.