Cosmogenic Nuclide Memory of Rocks (CoNMoR)

The Greenland Ice Sheet (GIS) is the only remaining ice sheet on the Northern Hemisphere and if it melted completely, global sea level would rise by 7.4 m. In the recent geological past, the GIS has been significantly smaller during warm interglacial periods when global temperatures were higher than present. As such, the melting of the GIS as a response to ongoing and future global warming represent a major societal concern because of the resulting rise in global sea levels. The aim of this project is to develop and test a new method - ConMoR - to constrain how the GIS reacted to warming in past interglacial periods when global temperatures were c. 1°C higher than the pre-industrial, i.e. an analogue to what we might expect over the next 100 years if we meet the emission targets of the Paris Agreement. Based on a number of river samples originating from below the ice sheet in S Greenland we will use the cosmogenic nuclides memory in sand grains to constrain the size of the GIS during previous warm interglacial periods during the last ~2 million years (Myr). If successful, this method can be expanded to cover the entire GIS as well as glaciers and ice sheets worldwide. This will enable us to solve a long-standing question about the long-term sensitivity of the GIS during periods when temperatures were warmer than at present and provide crucial societal information to improve projections of future responses to global warming.