New evidence shows Greenland’s ice sheet once melted completely, revealing a tundra below.
New research provides the first direct evidence that the center, not just the edges, of Greenland’s ice sheet melted in the recent geological past and the now-ice-covered island was then home to a green, tundra landscape.
Implications for Global Sea Levels These findings confirm that Greenland’s ice melted and the island greened during a prior warm period likely within the last million years, suggesting that the giant ice sheet is more fragile than scientists had realized.
So he and his colleagues requested a sample from the bottom of the GISP2 core held at the National Science Foundation Ice Core Facility in Lakewood, Colorado.
“It lets us know that Greenland’s ice melted and there was soil,” said Mastro, “because poppies don’t grow on top of miles of ice.”
According to recent data, Greenland’s ice sheet once entirely melted, exposing a tundra underneath. This implies heightened susceptibility to the effects of climate change and notable prospective elevations in sea level.
The latest findings offer the first concrete proof that Greenland’s ice sheet melted in its entirety, not just around its edges, and that a verdant tundra once covered the ice-covered island.
Amazing Findings in Geology.
The researchers reexamined a few inches of sediment from the bottom of a two-mile-deep ice core that was taken in 1993 at Greenland’s very center for their study, which was published in the Proceedings of the National Academy of Sciences on August 5. They were astounded to find soil that included fungi, willow wood, insect parts, and a perfectly preserved poppy seed.
As far as the implications of the fossils’ relationship to the melting of the Greenland ice sheet due to human-caused climate change go, “these fossils are beautiful,” but “yes, we go from bad to worse,” says Paul Bierman, a scientist at the University of Vermont who co-led the recent study with UVM graduate student Halley Mastro and nine other researchers.
repercussions for sea levels worldwide.
These discoveries demonstrate that Greenland’s ice melted and the island turned green during a previous warm period that occurred most likely within the last million years, indicating that the massive ice sheet may be more vulnerable than previously thought.
The majority of the island had to melt if the ice covering its center did. “And probably for many thousands of years,” Bierman remarked, providing enough time for the formation of soil and the establishment of an ecosystem.
An expert in climate science at Penn State, Richard Alley, commented, “This new study confirms and extends that a lot of sea-level rise occurred at a time when causes of warming were not especially extreme, providing a warning of what damages we might cause if we continue to warm the climate.”. “.
The sea level is currently increasing by more than one inch every ten years. And it’s getting quicker and quicker, Bierman remarked. When today’s kids become grandparents at the end of the century, it’s probably going to be several feet higher. Furthermore, he stated that if greenhouse gas emissions from burning fossil fuels are not drastically decreased, Greenland’s ice would melt almost entirely over the course of the next several centuries to millennia, raising sea levels by about 23 feet.
“Consider Miami, Mumbai, Boston, New York, or any other coastal city in the world, and add twenty feet or more to the sea level,” Bierman said. The thing submerges. Avoid purchasing a beach house. “.
Reappraising the Ice Age of Greenland.
In 2016, Columbia University’s Joerg Schaefer and colleagues conducted tests on rock from the bottom of the same 1993 ice core (known as GISP2) and published a then-controversial study claiming that the Greenland ice sheet could be as old as 11.1 million years, that there were extended periods without ice during the Pleistocene (the geological period that began 20.7 million years ago), and that 90% of the rest of Greenland would melt if the ice at the GISP2 site melted. The long-held myth that Greenland is an unforgiving ice fortress that has been frozen solid for millions of years has mostly been debunked by this.
2019 saw the reexamination of a second ice core, this one taken at Camp Century close to the Greenland coast in the 1960s, by Paul Bierman of UVM and a global team. When they found twigs, seeds, and insect parts at the bottom of that core, they were astounded to learn that the ice there had melted only 416,000 years ago. Put another way, the ice fortress’s walls had collapsed far sooner than had been previously thought to be feasible.
Signs of Former Arctic Ecosystems.
Professor Bierman of UVM’s Rubenstein School of Environment and Natural Resources and fellow at the Gund Institute for Environment said, “Once we made the discovery at Camp Century, we thought, ‘Hey, what’s at the bottom of GISP2?'”. Despite a great deal of research on the ice and rock in that core, he claimed that “no one’s looked at the 3 inches of till to see if it’s soil and if it contains plant or insect remains.”. In order to obtain a sample from the bottom of the GISP2 core, which is kept at the National Science Foundation Ice Core Facility in Lakewood, Colorado, he and his colleagues made this request.
This latest research published in PNAS, backed by the U. s. The National Science Foundation confirms the validity of the “fragile Greenland” theory from 2016. Furthermore, it intensifies the cause for alarm by demonstrating that the island experienced sufficient warmth for an extended period of time, allowing a whole tundra ecosystem—possibly including dwarfed trees—to emerge where ice currently sits two miles below the surface.
Bierman stated, “We now have concrete proof that not only was the ice gone, but that plants and insects were thriving there as well.”. And you can’t argue with that. Calculations and models are not necessary. “.
Revealing the History.
As a post-doctoral associate in Bierman’s lab at UVM and a recent PhD graduate, geoscientist Andrew Christ made the initial discovery that intact biological material—rather than just gravel and rock—was present at the bottom of the ice core. Halley Mastro then took up the case and dug into the details.
“It was incredible,” she remarked. What had appeared to be little more than specks floating on the surface of the melted core sample under the microscope turned out to be a window into a tundra landscape. Mastro was able to identify spores from spikemoss, the bud scale of a young willow, and the compound eye of an insect by working with Dorothy Peteet, a macrofossil expert at the Lamont-Doherty Earth Observatory and co-author of the new study. “And then we found Arctic poppy, just one seed of that,” Mastro said. That little flower is quite adept at withstanding the cold. “.
However, not that excellent. Since poppies don’t grow on top of miles of ice, Mastro explained, “it lets us know that Greenland’s ice melted and there was soil.”. “.
