At the end of the last ice age, the Earth slowly warmed by 4–7 °C globally14 and lost almost two-thirds of its land ice in the process. That raised sea level by 120 metres, at rates often exceeding a metre per century1. It seems that nothing in the present ice-sheet configuration would rule out similar rates in future. How much of the remaining 65 metres’ worth of land ice will humans melt if we warm the planet by a further several degrees?
At the end of the last ice age, the ice sheet extended as far south as 40N (New York and Chicago). By contrast, the southern tip of Greenland is at 60N. Temperatures in the center of the Greenland ice sheet have not gotten above freezing at any time this year.
Besides the fact that the remaining ice is located much further north, most is at much higher elevation and the surface area is much smaller than it was 15,000 years ago. Melt rates producing sea level rise of one metre per century are completely implausible.
Rahmstorf has absolutely no idea what he is talking about.