Greenland Ice Sheet: Three Futures

The Greenland Ice Sheet holds enough water to raise the world’s sea level by over 7 meters (23 feet). Rising atmosphere and ocean temperatures have led to an ice loss equivalent to over a centimeter increase in global mean sea-level between 1991 and 2015. Large outlet glaciers, rivers of ice moving to the sea, drain the ice from the interior of Greenland and cause the outer margins of the ice sheet to recede. Improvements in measuring the ice thickness in ice sheets is enabling better simulation of the flow in outlet glaciers, which is key to predicting the retreat of ice sheets into the future.

Recently, a simulation of the effects of outlet glacier flow on ice sheet thickness coupled with improved data and comprehensive climate modeling for differing future climate scenarios has been used to estimate Greenland’s contribution to sea-level over the next millennium. Greenland could contribute 5–34 cm (2-13 inches) to sea-level by 2100 and 11–162 cm (4-64 inches) by 2200, with outlet glaciers contributing 19–40 % of the total mass loss. The analysis shows that uncertainties in projecting mass loss are dominated by uncertainties in climate scenarios and surface processes, followed by ice dynamics. Uncertainties in ocean conditions play a minor role, particularly in the long term. Greenland will very likely become ice-free within a millennium without significant reductions in greenhouse gas emissions.

This movie shows the evolution of several regions of the Greenland Ice Sheet between 2008 and 2300 based on three different climate scenarios. Each scenario reflects a potential future climate outcome based on current and future greenhouse gas emissions. The scenario labelled "LOW" here is based on the Representative Concentration Pathway (RCP) 2.6 climate scenario while the one labelled "MEDIUM" is based on RPC 4.6. The visualization labelled "HIGH" is based on RPC 8.5 and reflects the current trajectory of emissions in the 21st century. The regions shown in a violet color are exposed areas of the Greenland bed that were covered by the ice sheet in 2008.

The data sets used for these animations are the control (“CTRL”) simulations and were produced with the open-source Parallel Ice Sheet Model . All data sets for this study are publicly available at the NSF Arctic Data Center