Rapid melting of North America’s Laurentide ice sheet 9,000 and 7,600 years ago caused sea level to rise by up to 1.3 cm per year, according to research published online this week in Nature Geoscience. The summer air temperature rise that led to these melt pulses is similar to that recently reported for Greenland, suggesting that predictions of future sea level rise may be too low.
Anders Carlson and colleagues used marine and terrestrial records to reconstruct the demise of the Laurentide ice sheet during the Holocene era, which started about 10,000 years ago. Their simulations of the most rapid melting episodes show that the driving factors for the thinning of the ice sheet were increased solar radiation and increasing summer temperatures. Although the radiation at present is much lower, similar temperature increases have been recorded in Greenland during the past decades.
In an accompanying News and Views, Mark Siddall writes ‘Carlson and colleagues…show that the decay of the Laurentide ice sheet in the early Holocene was extremely fast during the periods they consider…. Their work suggests that, in principle, future melt rates on the order of one metre per century are certainly not out of the question.’