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The study, published in the journal Nature, is the first to very thoroughly reconstruct Greenland’s ice loss during the Holocene, the geological epoch that paved the way for humanity to flourish 12,000 years ago.
According to the study, which is based on data from core drilling in models and several kilometers thick ice, 36 billion tons of ice will melt over the next ten years if global warming continues as it does now. It is enough to raise the sea level by 10 centimeters.
Until the late 1990s, the Greenland ice sheet was largely in equilibrium, growing both from snow in winter and from melting and glaciers like calves.
The upset balance
But escalating climate change has upset this balance and net losses are flowing into the North Atlantic.
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The Greenland ice sheet contains enough frozen water that the sea level would rise seven meters if it all melted. But if the tipping point is passed and the melting can no longer be stopped, it will probably still be several thousand years before all the ice melts.
Such a turning point can occur even with a temperature rise of 2 degrees above the pre-industrialization level, the researchers say.
Disaster for coastal communities
But even in the short term, a rise in sea level of a few tens of centimeters will be catastrophic for many coastal communities around the world.
Areas with a total of 300 million people, most of them in poor areas of the world, will already be heavily exposed by 2050 to regular flooding as a result of storm surge, previous research shows.
Last year, Greenland lost 500 million tonnes of ice and meltwater, contributing to 40 percent of the sea level rise in 2019, mostly in a single year since satellite registration began in 1978.
Scientists sound the alarm
The new normal
If the world does not drastically reduce CO2 emissions from burning fossil fuels, such sea level rise will be the new normal, says geology professor Jason Briner of the University of Buffalo in New York, who is the lead author of the new study.
– No matter how high future CO2 emissions are, the Greenland ice sheet will lose more ice in this century than in any other century, even in the warmest period in the past 12,000 years, Briner says.
– But the study also gives me hope that humanity has the opportunity to determine the future of the thaw and the rise in sea level, he emphasizes.
The first continuous record of the Greenland Ice Sheet took five years to complete, based on close collaboration between ice-drilling scientists, modeling scientists, remote sensing experts and paleoclimatologists.
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The 12,000-year timeline makes it easier to distinguish natural fluctuations in the balance of the ice sheet from the effects of man-made climate change.
Can be limited
If it manages to limit global warming to less than 2 degrees, the main goal of the Paris Agreement in 2015, it should limit Greenland’s contribution to sea level rise this century to around 2 centimeters, according to the study.
But anyway, in any scenario, the sea level will continue to rise in the 22nd century and beyond.
– There is no doubt that we will see a remarkable rise in sea level in this century. But without a course correction now, the increase in the next century could change the lives of most people in the world, he says.
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Also Antarctica
Until 2000, the main cause of sea level rise was melting glaciers and the expansion of water into the ocean as it warmed.
But in the past two decades, the inner ice of Greenland and Antarctica has become by far the most important source of sea level rise.
When all sources other than the Greenland ice sheet are taken into account, the UN’s IPCC climate panel has calculated that sea level rise will be just under a meter by the end of this century.
