Warning signs that a portion of the Greenland ice sheet is destabilizing

An international group of scientists has determined that the central-west portion of the massive Greenland ice sheet is destabilizing and is getting close to a critical transition or tipping point.

This transition could open the door to a much higher rate of melting in the near future, which may lead to an even more rapid rise in global sea levels.

The primary culprit to the melting of ice sheets is the warming of the planet due to human-induced climate change. As the top of the ice sheet (which is normally the coldest due to its high elevation) melts, it slowly sinks into warmer surrounding air at the lower elevation, which leads to accelerated melting. Lower albedo (reduced reflectivity of the ice sheet) may also be playing a role as well.

From earlier studies, the critical global mean temperature brink is somewhere between 0.8 and 3.2 degrees Celsius above pre-industrial levels. If this temperature threshold is crossed, the entire ice sheet could completely melt out in thousands or even hundreds of years. The result would be a rise of global sea levels by more than 7 meters, which would also lead to a collapse of the Atlantic Meridional Overturning Circulation (AMOC). The AMOC helps keep Europe's climate relatively mild for a region that is has a significant amount of land that is located above 50 degrees north.

Scientists must also account for possible negative feedback mechanisms, such as increased precipitation and resulting snowfall, which may reduce the rate of ice loss.

For more information on this study, see the story from the Potsdam Institute for Climate Impact Research.

Link to the actual study.