Substantial contribution to sea-level rise during the last interglacial from the Greenland ice sheet

During the last interglacial period (the Eemian), global sea level was at l east three metres, and probably more than five metres, higher than at prese nt(1,2). Complete melting of either the West Antarctic ice sheet or the Gre enland ice sheet would today raise sea levels by 6-7 metres. But the high s ea levels during the last interglacial period have been proposed to result mainly from disintegration of the West Antarctic ice sheet(3), with model s tudies attributing only 1-2 m of sea-level rise to meltwater from Greenland (4,5). This result was considered consistent with ice core evidence(4), alt hough earlier work had suggested a much reduced Greenland ice sheet during the last interglacial period(6). Here we reconsider the Eemian evolution of the Greenland ice sheet by combining numerical modelling with insights obt ained from recent central Greenland ice-core analyses. Our results suggest that the Greenland ice sheet was considerably smaller and steeper during th e Eemian, and plausibly contributed 4-5.5 m to the sealevel highstand durin g that period. We conclude that the high sea level during the last intergla cial period most probably included a large contribution from Greenland melt water and therefore should not be interpreted as evidence for a significant reduction of the West Antarctic ice sheet.