With ongoing carbon dioxide emissions from the burning of fossil fuels, the atmosphere of Earth heats up, which has dramatic consequences for the ice sheets. In a new study, researchers focused on the Greenland Ice Sheet, which holds so much ice that a complete melting would cause the global sea level to rise by 7 m (23 feet).
The Greenland Ice Sheet (GIS) covers 1.7 million km2 (660,200 square miles) in the Arctic.
Mass loss of the GIS is one of the main contributors to sea level rise. Between 2003 and 2016, it has lost mass at a rate of 255 gigatons (billions of tons) per year, with increasing atmospheric carbon dioxide from anthropogenic emissions expected to lead to further mass loss.
If the GIS melts entirely, global sea level would rise about 7 m, but scientists aren’t sure how quickly the ice sheet could melt.
Air and water temperature, ocean currents, precipitation and other factors all determine how quickly the GIS melts and where it loses ice.
The complexity of how those factors influence each other, along with the long timescales scientists need to consider for melting an ice sheet of this size, make it difficult to predict how the ice sheet will respond to different climate and carbon emissions scenarios.
Previous research identified global warming of between 1 and 3 degrees Celsius as the threshold beyond which the GIS will melt irreversibly.
To more comprehensively model how the ice sheet’s response to climate could evolve over time, Potsdam Institute for Climate Impact Research’s Dr. Dennis Höning and colleagues used a complex model of the whole Earth system, which includes all the key climate feedback processes, paired with a model of ice sheet behavior.
They first used simulations with constant temperatures to find equilibrium states of the ice sheet, or points where ice loss equaled ice gain.
Then they ran a set of 20,000-year-long simulations with carbon emissions ranging from 0 to 4,000 gigatons of carbon.
From among those…
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