The Greenland ice sheet during LGM – a model based on field observations

Research output: Contribution to conferenceConference abstract for conferenceResearch

In the light of recent years¿ intense discussion on the role of Greenland Ice Sheet in global warming its reaction to past climatic change can contribute valuable information. We have updated the evidence for LGM (c. 23-20 kaBP) icesheet coverage. previous reviews An important part of the main The issue is complicated by the circumstance that during LGM (Last glacial maximum) the ice sheet margins around the whole perimeter stood on the shelf and “classical” evidence, such as large moraine belts, extensive sandurs and major drainage diversions do not apply. The first estimates were therefore based on observations on land, such as weathering limits on coastal mountains, major moraine belts, and altitudes of marine limits. Extrapolation from this gave estimates of LGM ice cover on the shelf ranging from inner to outer shelf, often under the assumption that it had to be either or, and not in between. Also, it was often assumed that if it could be demonstrated that the margin reached the shelf edge in one area, this should apply to the whole perimeter. Modelling, mainly on the basis of palaeoclimatic data, have presented a similar disparity between maximum and minimum estimates, assessing the Greenland ice sheet¿s contribution to Holocene sea level rise to between 0.3 and 2.6 m. Recent years have given spectacular new insight into shelf-ice distribution and behaviour - especially by detailed seismic surveys on the shelf and cosmogenic isotope surface exposure dating on coastal mountains. We combine this new evidence with the older observations. This model is conservative because it is, as far as possible, based on tangible evidence minimising the amount of speculation. The LGM ice sheet in this model covered c. 2.7 mio km2, 65% more than the present. Two thirds of this excess relative to the present was on the shelf beyond the coast, and only one third on land and in fjord basins. The evidence also indicates that the glacial regimes varied between regions.
Original languageEnglish
Publication date2011
Number of pages1
Publication statusPublished - 2011
EventQuaternary Glacial and Climate Extremes, - Longyearbyen, Norway
Duration: 1 Jun 20114 Jun 2011

Conference

ConferenceQuaternary Glacial and Climate Extremes,
CountryNorway
CityLongyearbyen
Period01/06/201104/06/2011

ID: 34261090