By 2100, Greenland will likely be shedding ice sooner than at any time previously 12,000 years, scientists report October 1 in Nature.
Because the 1990s, Greenland has shed its ice at an growing fee (SN: 8/2/19). Meltwater from the island’s ice sheet now contributes about 0.7 millimeters per 12 months to international sea degree rise (SN: 9/25/19). However how does this speedy loss stack up in opposition to the ice sheet’s current historical past, together with throughout a 3,000-year-long heat interval?
Glacial geologist Jason Briner of the College at Buffalo in New York and colleagues created a grasp timeline of ice sheet modifications spanning almost 12,000 years, from the daybreak of the Holocene Epoch 11,700 years in the past and projected out to 2100.
The researchers mixed local weather and ice physics simulations with observations of the extent of previous ice sheets, marked by moraines. These rocky deposits denote the perimeters of historic, bulldozing glaciers. New fine-tuned local weather simulations that embrace spatial variations in temperature and precipitation throughout the island additionally improved on previous temperature reconstructions.
In the course of the previous heat episode from about 10,000 to 7,000 years in the past, Greenland misplaced ice at a fee of about 6,000 billion metric tons every century, the group estimates. That fee remained unmatched till the previous twenty years: From 2000 to 2018, the typical fee of ice loss was comparable, at about 6,100 billion tons per century.
Over the subsequent century, that tempo will speed up, the group says. How a lot depends upon future greenhouse gasoline emissions: Underneath a lower-emissions state of affairs, ice loss is projected to common round 8,800 billion tons per century by 2100. With increased emissions, the speed of loss may ramp as much as 35,900 billion tons per century.
Decrease emissions may gradual the loss, however “it doesn’t matter what humanity does, the ice will soften this century at a sooner clip than it did throughout that heat interval,” Briner says.