New study shows Greenland ice loss will raise global sea levels by almost a foot

study, published on Monday in the journal Nature Climate Change, found that the total loss of ice on the Greenland ice sheet would cause sea levels to rise by at least 10 inches, regardless of climate warming scenarios. This is typically the same amount that the global seas have already risen over the past century due to Greenland, Antarctica and thermal expansion (when ocean water expands as it warms) combined.

Researchers at the Geological Survey of Denmark and Greenland observed changes in the volume of the ice sheet in and around Greenland and saw that meltwater runoff was a major factor. Using a “well-established theory,” scientists were able to determine that about 3.3% of the Greenland ice sheet, equivalent to 110 trillion tons of ice, will inevitably melt as the ice sheet reacts to changes that have already taken place.

According to lead author Jason Box, a scientist at the Geological Survey of Denmark and Greenland, sea level rise due to melting ice will occur “regardless of any foreseeable future climate change this century.” “Technically, this water is already under the bridge.”

Although the authors did not specify a time scale, they predict that sea level change could occur between now and the end of the century.

The study focused solely on estimating a minimum or “very conservative lower bound” for sea level rise from the melting in Greenland, “and it’s almost certain that if the climate continues to warm, sea levels will only rise,” Box said. .

Massive ice sheets can melt quickly when the air temperature is warm, but warmer ocean water also erodes the sheet at the edges.

Conclusions come on the heels Sea Level Rise Report 2022 released last year by the National Oceanic and Atmospheric Administration, which found that the US coastline could expect sea levels to rise by 10 to 12 inches in the next 30 years. According to the report, this will cause the tides to occur more than 10 times more often, and storm surges to spread further inland.

There is so much ice in Greenland that if all of it melted, sea levels could rise by about 25 feet around the world. The researchers note that a 20-foot rise in sea levels does not mean it will rise evenly across the globe, leaving some places devastated and sea levels falling elsewhere.

As places like Greenland lose ice, they also lose the gravitational pull of ice on water, meaning sea levels in Greenland are falling and rising elsewhere, said William Colgan, senior scientist Geological Survey of Denmark and Greenland. The speed of this change is a challenge, Colgan told CNN’s Bill Weir during a summer 2021 research trip.

“It will be very difficult to adapt to such rapid changes,” Kolgan said, standing on the Jakobshavn glacier in Greenland, where the fjord is full of ice that has broken away from the glacier.

Before human-induced climate change began, temperatures around 32 degrees Fahrenheit were unheard of in Greenland. But since the 1980s, the region has warmed by about 1.5 degrees per decade — four times faster than the global rate — raising the possibility that temperatures will break the melt threshold.

Several days of unusually warm weather in northern Greenland recently caused a rapid melt with temperatures around 60 degrees – 10 degrees warmer than normal for this time of year, scientists told CNN.

According to the US National Snow and Ice Data Center, the amount of ice that melted in Greenland between July 15 and July 17 alone – 6 billion tons of water per day – would be enough to fill 7.2 million Olympic-size swimming pools. .

Global scientists said the trends under which climate change is accelerating are very clear, and that unless emissions are immediately contained, many of the more extreme melting events will continue to occur more intensely and more frequently.

CNN’s René Marsh and Angela Fritz contributed to this report.

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