Letter. High rates of sea-level rise during the last interglacial period

The last interglacial period, Marine Isotope Stage (MIS) 5e, was characterized by global mean surface temperatures that were at least 2 °C warmer than present. Mean sea level stood 4–6 m higher than modern sea level, with an important contribution from a reduction of the Greenland ice sheet1. Although some fossil reef data indicate sea-level fluctuations of up to 10 m around the mean, so far it has not been possible to constrain the duration and rates of change of these shorter-term variations. Here, we use a combination of a continuous high-resolution sea-level record, based on the stable oxygen isotopes of planktonic foraminifera from the central Red Sea, and age constraints from coral data to estimate rates of sea-level change during MIS-5e. We find average rates of sea-level rise of 1.6 m per century. As global mean temperatures during MIS-5e were comparable to projections for future climate change under the influence of anthropogenic greenhouse-gas emissions, these observed rates of sea-level change inform the ongoing debate about high versus low rates of sea-level rise in the coming century.<br/

Identifying the causes of sea-level change

Global mean sea-level change has increased from a few centimetres per century over recent millennia to a few tens of centimetres per century in recent decades. This tenfold increase in the rate of rise can be attributed to climate change through the melting of land ice and the thermal expansion of ocean water. As the present warming trend is expected to continue, global mean sea level will continue to rise. Here we review recent insights into past sea-level changes on decadal to millennial timescales and how they may help constrain future changes. We find that most studies constrain global mean sea-level rise to less than one metre over the twenty-first century, but departures from this global mean could reach several decimetres in many areas. We conclude that improving estimates of the spatial variability in future sea-level change is an important research target in coming year