At the current rate of greenhouse gas emissions, Greenland will lose more ice this century than what it has lost in the last 12,000 years. A multidisciplinary team of scientists brought together expertise in climate modeling, remote sensing, and paleoclimate research to predict the behavior of the Greenland Ice Sheet through 2100.
The researchers used ice sheet modeling to reconstruct Greenland’s ancient climate. They looked at real-world measurements such as satellite data to validate the accuracy of the model, and then analyzed how the ice sheet has changed over time in the southwestern part of the country dating back to the Holocene period.
Meanwhile, Professor Jesse V. Johnson and postdoctoral researcher Jacob Downs of the University of Montana reconstructed the past climate by studying concentrations of gases trapped in the ice. The experts used a numerical model of ice dynamics, incorporating data from ice sheet retreat and past temperatures. This allowed them to estimate how snowfall has fluctuated alongside temperature changes over the past 12,000 years.
“There is so much incredible science that we were totally ignorant of,” said Professor Johnson. “We learned how the climate of the past can be found by measuring the waxes in leaves trapped in the mud under lakes and how microfossils found in the ocean can tell you the water’s temperature. We really didn’t know much about this area of paleoclimate proxies going into this project, but came away fascinated with what they can tell us about Earth’s climate history.”
The study ultimately revealed that under a high emissions scenario, the Greenland Ice Sheet is set to lose four times its largest amount of ice in 12,000 years. If emissions are significantly reduced, however, the ice retreat will be only slightly larger than what Greenland has experienced in the same time frame.
“Basically, we’ve altered our planet so much that the rates of ice sheet melt this century are on pace to be greater than anything we’ve seen under natural variability of the ice sheet over the past 12,000 years,” said study lead author Professor Jason Briner of the University at Buffalo.
According to Professor Johnson, the study findings cannot be overstated. He said that comparing today’s potential ice loss with that of the last 12,000 years is important for gaining perspective.
“Such comparisons are critical in understanding what we are living through now,” said Professor Johnson. “These changes are much greater than what has been experienced in more than twice the recorded history of homo sapiens. We often wonder what our ancestors would have done when faced with similar circumstances. In this case, the answer is that we don’t know. Our ancestors never experienced anything like this.”
“Our findings are yet another wake-up call, especially for countries like the U.S.,” said Professor Briner. “Americans use more energy per person than any other nation in the world. Our nation has produced more of the CO2 that resides in the atmosphere today than any other country. I think Americans need to go on an energy diet.”
The study is published in the journal Nature.
By Chrissy Sexton, Earth.com Staff Writer