If global average temperatures reach 1.6 degrees C (2.9 degrees F.) above preindustrial levels, the iconic ice sheet probably will tip toward irreversible loss, a new study finds.
With a rise already of 0.8 degrees C, global average temperatures already are halfway there.
In recent years, global climate talks have focused on trying to hold human-triggered warming to 2 degrees C by the end of the century. The study implies that even that goal would be too warm for winter snows to make up for summer melt for one of the planet's two major land-topping ice sheets.
The rate of ice loss expected for warming of 1.6 degrees is slow, occurring over 50,000 years, the researchers estimate. Higher climate-change temperatures would accelerate the process.
The ice sheet could lose 20 percent of its mass over the next 500 years from temperature increases associated with so-called business-as-usual greenhouse-gas emissions through century's end. In this case, the study indicates, the ice sheet could vanish in 2,000 years.
The loss of Greenland's ice sheet would raise global sea levels by an average of nearly 24 feet.
An earlier study, incorporated into the Intergovernmental Panel on Climate Change's 2007 global warming reports, suggested that the point of no return hovered around 3.1 degrees C. But even as those reports were released, researchers noted that more research, which was published too late to be included in the IPCC volumes, suggested that Greenland's ice sheet was responding to global warming faster than the reports indicated. Read the full report here.
Source: by Pete Spotts, Staff writer, The Christian Science Monitor.
