If human society does not drastically curtail greenhouse gas emissions, the rate of ice loss in Greenland this century will be much higher than anything in the past 12,000 years. These are the results of a new study by scientists, the results are published by the journal Nature.
The study uses ice sheet modeling to understand the past, present and future of the Greenland ice sheet. Scientists have used new, detailed reconstructions of the ancient climate to create a model and have confirmed its conformity with real measurements of the modern and ancient dimensions of the ice sheet.
The current decline of the ice sheet is viewed in a historical context, highlighting how extreme and unusual the predicted losses in the 21st century can be.
“In fact, we have changed our planet so much that the rate of ice sheet melting in this century will be greater than anything we have seen with natural ice sheet variability over the past 12,000 years,” explains Jason Briner, Ph.D. and professor of geology. University at Buffalo College of Arts and Sciences. Briner led collaborative research, coordinating the work of scientists from different disciplines and institutions.
“If the world goes on a massive energy diet according to what the Intergovernmental Panel on Climate Change is calling RCP2.6, our model predicts that the rate of mass loss of the Greenland Ice Sheet this century will be only slightly higher than anything that happened in past, over the past 12,000 years, ”adds Briner. “But more worrisome is that under the high RCP8.5 scenario, the rate of shield mass loss could be about four times the highest observed under natural climate variability over the past 12,000 years.”
He and his colleagues say the results confirm the need for countries around the world to take action now to cut emissions, slow ice sheet shrinking, and mitigate sea-level rise. The research was funded in large part by the US National Science Foundation.
The study involved climate modelers, ice core researchers, remote sensing and paleoclimate researchers from UB, NASA’s Jet Propulsion Laboratory (JPL), University of Washington (UW), Columbia University’s Lamont-Doherty Earth Observatory (LDEO), University of California, Irwin (UCI) and other agencies.
This multidisciplinary team used a modern ice sheet model to simulate changes in the southwestern sector of the Greenland Ice Sheet, starting from the beginning of the Holocene about 12,000 years ago and extending over 80 years to 2100.
Scientists tested the accuracy of the model by comparing simulation results with historical data. The simulated results are in good agreement with data tied to actual measurements of the ice sheet from satellites and aerial photographs in recent decades, as well as field studies that define the ancient boundaries of the ice sheet.
Although the project focused on southwestern Greenland, research shows that changes in the rate of ice melting there tend to be closely related to changes throughout the ice sheet.
The study is making an important contribution by plotting the past, present and future of the Greenland Ice Sheet, Briner said, and the results are sobering.
“We have long-term plots of temperature change, from past to present to future, that show the effect of greenhouse gases on Earth’s temperature. And, now, for the first time, we have a long-term graph of exposure to this temperature – in the form of the melting of the Greenland ice sheet – from the past to the present and the future. It opens our eyes to the situation, ”concludes Briner.