According to a new report led by the U.S. Geological Survey, the U.S. “faces the possibility of much more rapid climate change by the end of the century than previous studies have suggested.” The report, commissioned by the U.S. Climate Change Science Program, found that global sea levels could rise higher than a 2007 U.N. Intergovernment Panel on Climate Change (IPCC) study had concluded:
In one of the report’s most worrisome findings, the agency estimates that in light of recent ice sheet melting, global sea levels could rise as much as 4 feet by 2100. The intergovernment panel had projected a rise of no more than 1.5 feet by that time, but satellite data over the last two years show the world’s major ice sheets are melting much more rapidly than previously thought. The Antarctic and Greenland ice sheets are losing an average of 48 cubic miles of ice a year, equivalent to twice the amount of ice in the Alps.
The lead scientist for the report’s chapter on ice sheets said the models used by the IPCC “did not factor in some of the dynamics that scientists now understand about ice sheet melting” such as “a process of ‘lubrication,’ in which warmer ocean water gets underneath coastal ice sheets and accelerates melting.”
The Wonk Room’s Brad Johnson has more on ice sheet melting.