In 1966, US Army scientists drilled down through nearly a mile of ice in northwestern Greenland and pulled up a fifteen-foot-long tube of dirt from the bottom. Then this frozen sediment was lost in a freezer for decades. It was accidentally rediscovered in 2017.
In 2019, University of Vermont scientist Andrew Christ looked at it through his microscope and couldn t believe what he was seeing: twigs and leaves instead of just sand and rock. That suggested that the ice was gone in the recent geologic past and that a vegetated landscape, perhaps a boreal forest, stood where a mile-deep ice sheet as big as Alaska stands today.
Print article At first, Andrew Christ was ecstatic. In soil taken from the bottom of the Greenland ice sheet, he’d discovered the remains of ancient plants. Only one other team of researchers had ever found greenery beneath the mile-high ice mass. But then Christ determined how long it had been since that soil had seen sunlight: Less than a million years. Just a blink of an eye in geologic terms. And it dawned on him. If plants once grew at multiple spots on the surface of Greenland, that meant the ice that now covers the island had entirely melted. And if the whole Greenland ice sheet had melted once in the not-so-distant past, that meant it could go again.
Trench construction in 1960 at Camp Century, an Arctic U.S. military scientific research base in Greenland. (Source: U.S. Army Corps of Engineers, Cold Regions Research and Engineering Laboratory, via Courthouse News)
PARIS (AFP) The ice sheet atop Greenland which holds enough frozen water to swamp coastal cities worldwide has melted to the ground at least once in the last million years despite CO2 levels far lower than today, stunned scientists have reported.
The surprise discovery of plant fossils in soil samples extracted in the 1960s by U.S. army engineers from beneath over a mile of ice is smoking-gun proof that Greenland three times the size of Texas was covered with lichen, moss and perhaps trees in the not-so-distant past.
By SARAH KAPLAN | The Washington Post | Published: March 17, 2021 At first, Andrew Christ was ecstatic. In soil taken from the bottom of the Greenland ice sheet, he d discovered the remains of ancient plants. Only one other team of researchers had ever found greenery beneath the mile-high ice mass. But then Christ determined how long it had been since that soil had seen sunlight: Less than a million years. Just a blink of an eye in geologic terms. And it dawned on him. If plants once grew at multiple spots on the surface of Greenland, that meant the ice that now covers the island had entirely melted. And if the whole Greenland ice sheet had melted once in the not-so-distant past, that meant it could go again.