Greenland Was Once Ice Free. Scientists Worry It Could Be Again Soon

Greenland Was Once Ice Free. Scientists Worry It Could Be Again Soon

For a period about a million years ago Greenland wasn’t covered in ice. Researchers say the discovery suggests it’s possible the ice sheet could go away again.

Before now, scientists didn’t know whether Greenland’s ice sheet was so stable that it would just weather any climate changes, or if there were ever a period in which Greenland was, if not verdant, at least a bit rocky.

“We shouldn’t count on that ice sheet never melting again.”

A new analysis of rock samples suggests it was largely ice-free, perhaps for as long as 250,000 years.

Scientists were able to determine this because the bare rock during that time was exposed to cosmic rays in the atmosphere, says Marc Caffee, professor of physics and astronomy at Purdue University.

“We now have pretty conclusive evidence that for a time that ice wasn’t there,” Caffee says. “That’s big. That’s new. It’s probably not much different in temperature now than it was then, so we shouldn’t count on that ice sheet never melting again.”

Oceans could rise 20 feet

The Greenland ice sheet is the second largest ice cube on the planet, after the Antarctic ice sheet. If the Greenland ice sheet were to melt—if it is even possible for the ice sheet to melt—then it’s also possible that the planet’s oceans might rapidly rise five or six meters, or more than twenty feet, and wreak havoc on coastal cities worldwide.

 Get The Latest From InnerSelf

greenland melt 12 16Extent of surface melt over Greenland’s ice sheet on July 8 (left) and July 12 (right). Measurements from three satellites showed that on July 8, about 40 percent of the ice sheet had undergone thawing at or near the surface. In just a few days, the melting had dramatically accelerated and an estimated 97 percent of the ice sheet surface had thawed by July 12. In the image, the areas classified as “probable melt” (light pink) correspond to those sites where at least one satellite detected surface melting. The areas classified as “melt” (dark pink) correspond to sites where two or three satellites detected surface melting. The satellites are measuring different physical properties at different scales and are passing over Greenland at different times. As a whole, they provide a picture of an extreme melt event about which scientists are very confident. (Credit: Nicolo E. DiGirolamo, SSAI/NASA GSFC, and Jesse Allen, NASA Earth Observatory)

Caffee’s lab made the discovery by looking at rock samples that were recovered from beneath nearly two miles of ice in 1993. The researchers used a gas-filled magnet attached to a particle accelerator that is sensitive enough to detect the beryllium-10 and aluminum-26 atomic isotopes. These isotopes had been created by the cosmic rays striking the rock and had been hiding beneath the ice for more than a million years.

They report the results in Nature. Joerg Schaefer, a paleoclimatologist at Columbia University and the paper’s lead author, says it’s possible the Greenland ice sheet could go away again.

“Unfortunately, this makes the Greenland ice sheet look highly unstable,” says Schaefer. “With human-induced warming now well underway, loss of the Greenland ice has roughly doubled since the 1990s; during the last four years by some estimates, it shed more than a trillion tons [of ice].”

Coauthors are from Penn State University; the University of California-Berkeley; the University at Buffalo; and the US Army Cold Regions Research and Engineering Laboratory.

Source: Purdue University

Related Books:



follow InnerSelf on


 Get The Latest By Email



The Day Of Reckoning Has Come For The GOP
by Robert Jennings,
The Republican party is no longer a pro-America political party. It is an illegitimate pseudo-political party full of radicals and reactionaries whose stated goal is to disrupt, destabilize, and…
Why Donald Trump Could Be History's Biggest Loser
by Robert Jennings,
Updated July 2, 20020 - This whole coronavirus pandemic is costing a fortune, maybe 2 or 3 or 4 fortunes, all of unknown size. Oh yeah, and, hundreds of thousands, maybe a million, of people will die…
Blue-Eyes vs Brown Eyes: How Racism is Taught
by Marie T. Russell, InnerSelf
In this 1992 Oprah Show episode, award-winning anti-racism activist and educator Jane Elliott taught the audience a tough lesson about racism by demonstrating just how easy it is to learn prejudice.
A Change Is Gonna Come...
by Marie T. Russell, InnerSelf
(May 30, 2020) As I watch the news on the events in Philadephia and other cities in the country, my heart aches for what is transpiring. I know that this is part of the greater change that is taking…
A Song Can Uplift the Heart and Soul
by Marie T. Russell, InnerSelf
I have several ways that I use to clear the darkness from my mind when I find it has crept in. One is gardening, or spending time in nature. The other is silence. Another way is reading. And one that…