If people continue to emit greenhouse gases at the current rate, global sea levels could rise more than 38 centimeters by 2100, scientists found in a new study.
Greenhouse gases such as carbon dioxide emitted by human activities are major contributors to climate change and the warming of temperatures on planet earth, studies continue to show. As things warm up, the ice sheets in Greenland and Antarctica are melting. A new study by an international team of more than 60 ice, ocean and atmospheric scientists estimates how much these melting ice sheets will contribute to global sea levels.
“One of the biggest uncertainties about future sea-level rise is the contribution of the ice sheet,” said project leader and ice scientist Sophie Nowicki, now at Buffalo University and formerly with NASA’s Goddard Space Flight center in Maryland, said in a statement. “And how much the ice sheets contribute really depends on what the climate will do.”
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The results of this study show that if human greenhouse gas emissions continue at the rate at which they are currently, the melting ice sheets of Greenland and Antarctica will add more than 11 inches to global sea level. This new study is part of the Ice Sheet Model Intercomparison Project (ISMIP6) led by NASA Goddard.
The ISMIP6 team looked at how sea levels will rise between 2015 and 2100, and looked at how sea levels will change in a variety of CO2 emission scenarios
They found that Greenland’s melting ice sheet with high emissions (as we now see) extending over this period will add about 9 cm to the global sea level rise. If the emissions are lower, they estimate this number to be around 3 cm.
The loss of the ice cover in Antarctica is a little more difficult to predict, as the ice shelves on the west side of the continent will continue to erode, but East Antarctica could actually increase in mass due to rising temperatures due to increasing snowfall. Because of this, the team found a larger area of possible ice sheet loss here.
The team found that the loss of the Antarctic ice sheet could raise sea levels up to 30 cm, with West Antarctica causing sea level to rise up to 18 cm by 2100 with the highest projected emissions.
To be clear, however, these global sea level increases are only predictions for the years 2015 to 2100, so they do not take into account the significant ice sheet loss that has already occurred between the pre-industrial era and the present day.
“The Amundsen Sea region in West Antarctica and Wilkes Land in East Antarctica are the two regions that are most sensitive to ocean warming and changing currents and will continue to lose large amounts of ice,” said Helene Seroussi, ice scientist at Jet Propulsion NASA’s Southern California Laboratory, which led the modeling of the Antarctic ice sheet on the ISMIP6 project, said in the same statement.
“With these new results, we can focus our efforts in the right direction and know what needs to be worked on to further improve the projections,” said Seroussi.
These results are consistent with Estimates by the Intergovernmental Panel on Climate Change (IPCC), whose 2019 Special Report on Oceans and the Cryosphere showed that melting ice sheets would contribute about a third of all global sea level rise.
According to the 2019 IPCC report, melting ice sheets in Greenland will add between 8 and 27 cm to global sea level rise between 2000 and 2100. For Antarctica, the report estimates that the melting ice sheets will increase by 1.2 to 3 inches.
The results of this new work will help inform the next IPCC report, the sixth overall, which the same statement says should be published in 2022.
“The strength of ISMIP6 was to bring together most of the ice sheet modeling groups around the world and then connect with other ocean and atmosphere modeler communities to better understand what might happen to the ice sheets,” said Heiko Goelzer, a scientist of Utrecht University in the Netherlands, which are now working at the Norwegian research center NORCE in Norway, said in the same statement.
“It took over six years of workshops and conference calls with scientists from around the world working on ice sheet, atmosphere and ocean modeling to build a community that could ultimately improve our predictions for sea level rise,” Nowicki added who directed the Greenland Ice Sheet ISMIP6 project. “The reason it worked is because the polar community is small and we are all very interested in getting this future sea level problem right. We need to know these numbers.”
This work was published on September 17th in a special edition of The Cryosphere magazine.
Email Chelsea Gohd at [email protected] or follow her on Twitter @chelsea_gohd. Follow us on Twitter @Spacedotcom and on Facebook.