Simulation of Greenland ice sheet during the mid-Pliocene warm period

One of the key uncertainties in future sea-level projections is attributed to the Greenland ice sheet (GrIS). Studying the response of the GrIS to climate changes during the past warm periods is helpful for understanding future changes in the GrIS. In this study, using three global climate models (Community Atmosphere Model version 3.1 and version 4.0 and Norwegian Earth System Model) and a three-dimensional ice sheet model, we investigate the climate and ice sheet changes over Greenland during the mid-Pliocene warm period (similar to 3 Ma bp). The results show that the regionally averaged summer temperature over Greenland is 9.4-13.4 A degrees C higher during the mid-Pliocene period than during the pre-industrial era and the annual mean precipitation is 65.2-108.3 mm a(-1) greater. In response to this warm-wet climate, the GrIS shows a substantial decrease in size during the mid-Pliocene, with little ice existing along the eastern coast of Greenland. Compared to that simulated in the control run, the global sea level is approximately 7.8-8.1 m higher during the mid-Pliocene due to the decrease in the size of the GrIS. In addition, paleoclimate proxies also indicate that it is unlikely that a large-scale ice sheet exists over Greenland during the mid-Pliocene warm period.