Researchers have actually found that Greenland’s ice sheet melted considerably as just recently as 416,000 years back, suggesting its high level of sensitivity to environment modification. This melting led to a significant international sea-level increase, which integrated with today’s high CO2 levels, postures a severe hazard to our future. Credit: Joshua Brown/ UVM
Scientists report much of the Artic island’s ice melted as just recently as 416,000 years back, which has ramifications for sea-level increase.
Newly examined samples from beneath Greenland’s large ice sheet expose the Arctic island was significantly greener as just recently as 416,000 years back. This discovery challenges prior beliefs that Greenland’s enormous glacier, inhabiting approximately 80 percent of the 836,300- square-mile land mass, has actually been continuous for the last 2 and a half million years.
Ice Sheet Sensitivity to Climate Change
“We’re discovering the ice sheet is much more sensitive to climate change than we previously thought,” states Utah State University geoscientist TammyRittenour “This is a foreboding wake-up call.”
Rittenour, with coworkers from the University of Vermont and fourteen other organizations, reports findings in the July 20, 2023, problem of the journal Science Their research study is supported by the National Science Foundation.
In the Utah State University Luminescence Lab, college student Hawke Woznick utilizes screens to prepare sediment samples from Greenland’s Camp Century for OSL dating. USU Geosciences Professor Tammy Rittenour and coworkers reported findings about the samples in the July 20, 2023, problem of the journal Science Credit: USU/Levi Sim
Unstable Future of Greenland’s Ice Sheet
A greener Greenland implies the island’s formidable-appearing ice sheet– almost 2 miles thick in locations– is not as steady as presumed.
“We had always assumed the ice sheet has remained about the same for nearly 2.5 million years,” states Rittenour, teacher in USU’s Department ofGeosciences “But our investigation indicates it melted enough to allow the growth of moss, shrubs, and buzzing insects during an interglacial period called Marine Isotope Stage 11, between 424,000 to 374,000 years ago.”
The melting triggered a minimum of 5 feet of sea-level increase around the world, she states. “Some of our model scenarios suggest sea levels up to 20 feet higher than today.”
Utah State University Geosciences Professor Tammy Rittenour, envisioned in July 2023 at Iceland’s Langj ökull ice cap, research studies the paleoclimatology of severe environments throughout the world. Credit: USU/Tammy Rittenour
The Alarm of Rising CO2 Levels
“It was an unusually long period of warming with moderately elevated levels of carbon dioxide – CO2 – in the atmosphere,” Rittenour states. “What’s alarming about this finding is today’s CO2 levels are 1.5 times higher.”
Even if people suddenly stopped activities that add to greenhouse gas emissions, she states, “we’d still have inflated CO2 levels for hundreds, maybe even thousands, of years to come.”
That’s an anxious awareness, she states, with present rates at which Greenland’s ice sheet is defrosting.
“And that’s not taking Antarctica and other glacial areas into consideration,” Rittenour states. “The deglaciation has implications for the entire globe and is especially sobering for our coastal mega-cities, where so much of the world’s population resides.”
From Cold War Relics to Climate Science
The group’s analysis is an extension of research study began numerous years back, when the researchers discovered samples gathered from an amazing, Cold War- period military job.
“In 1960, the U.S. Army launched a top-secret effort called Project Iceworm in northwestern Greenland to build a network of mobile nuclear launch sites under the ice sheet,” Rittenour states. “As part of that project, they also invited scientists and engineers to conduct experiments in a highly publicized ‘cover’ project, known as Camp Century, to study the feasibility of working and carrying out military missions under ice and in extreme-cold conditions.”
Unlocking The Past From Forgotten Samples
Hampered by harsh blizzards and unsteady ice conditions, Project Iceworm’s spacious underground bunker and tunnels were deserted in1966 But sediment samples gathered at the bottom of a more than 4,000- foot-long ice core drawn out from the website have actually yielded the unexpected details about Greenland’s not-so-distant geologic past.
The frozen soil samples from the base of the Camp Century ice core were forgotten in a freezer for years, up until just recently re-discovered.
“We have very few samples from below the Greenland ice sheet, because most drilling missions stop when they reach the base of the ice,” Rittenour states. “These re-discovered Camp Century sediments represent a unique, unspoiled time capsule of past conditions.”
Advancements in Science Technology
While the frozen soil beinged in a freezer for more than 60 years, science innovation advanced. Rittenour, who is director of the USU Luminescence Laboratory, was welcomed to assist date the sediment.
“Because the samples remained frozen and largely untouched, I was able to use luminescence dating to determine the last time they were exposed to sunlight,” she states. “If researchers had examined the sediments in the past, we couldn’t have run any of the analyses we did for this paper.”
Rittenour states today’s investigative innovations make it possible for scientists to boil down a great record of what’s occurred in Greenland and other parts of the world.
“These once-lost, Cold War relics from a top-secret nuclear military base carved within the ice are continuing to tell their secrets, and forewarn us of the sensitivity of Earth’s climate,” she states. “If we can lose the far northwest portion of the Greenland ice sheet under natural conditions, then we’re treading dangerous waters given current elevated greenhouse gas conditions.”
For more on this research study:
Reference: “Deglaciation of northwestern Greenland during Marine Isotope Stage 11” by Andrew J. Christ, Tammy M. Rittenour, Paul R. Bierman, Benjamin A. Keisling, Paul C. Knutz, Tonny B. Thomsen, Nynke Keulen, Julie C. Fosdick, Sidney R. Hemming, Jean-Louis Tison, Pierre-Henri Blard, Jørgen P. Steffensen, Marc W. Caffee, Lee B. Corbett, Dorthe Dahl-Jensen, David P. Dethier, Alan J. Hidy, Nicolas Perdrial, Dorothy M. Peteet, Eric J. Steig and Elizabeth K. Thomas, 20 July 2023, Science
DOI: 10.1126/ science.ade4248
