New estimates using sheet modelling show that Greenland Ice loss this century may be faster than any other century in the past 12,000 yearsWhen the last ice age ended.
The scientists used reconstructions of ancient climates to drive their models, and then validated them against actual measurements of the ice sheet’s present-day and ancient size.
The study involved climate modellers, ice core scientists, remote sensing experts and paleoclimate researchers. The team used an ice sheet model to simulate changes in the southwestern part of the Greenland Ice Sheet from the start of the Holocene Epoch 12,000 years ago to 2100, 80 years later. Data was taken from ice cores to create maps of temperature and precipitation in the study area and used to power the ice sheet model simulations up to 1850, while other publicly available climate data was used for simulations beyond that.
The scientists tested the accuracy of the model by comparing its simulation results with historical measurements. The modeled results matched well with data linked to actual measurements of the ice sheet made by satellite and aerial surveys in recent decades, as well as field surveys that pinpointed the ice sheet’s ancient boundaries.
“By measuring beryllium-10 in rocks above the moraine, we have constructed a very detailed geological history of how the edge of the southwest Greenland ice sheet has moved through time.” Co-author Nicholas Young saysLDEO Associate Research Professor, PhD. “Moraines are large deposits found on the Earth’s surface that are at the edge of what was once an ice sheet or glacier. Measuring Beryllium-10 tells us how long that rock or moraine has been there, and therefore when the ice sheet was exactly in that location and deposited that rock. Surprisingly, the model reproduced the geological reconstruction very well, which gave us confidence that our ice sheet model is working well and giving us meaningful results. You can model whatever you like, and the model will always give you an answer, but you need a way to tell if the model is working well or not.”
While the project focused on southwest Greenland, studies have found that changes in the rate of ice loss there tend to track closely with changes in the ice sheet as a whole.
