Consequences of an accelerated melting of Greenland ice sheet on African monsoon: impact on Sahel region and heath vulnerability


June 21, 2018



Room B336, Building Mercator

A major uncertainty concerning the 21st century climate is the ice-sheet response to global warming. Paleodata indicates rapid ice-sheet destabilizations during the last deglaciation (as for instance Heinrich Event and melt water pulses). Moreover, the recent melting of Larsen B and C, ice shelf break, made the ice sheet more vulnerable. Ice sheet destabilization could therefore amplify the sea level rise and its evolution by the end of this century. These features had already been pinpointed in recent publications (Mulitza, Paleoceanography, 2008; Alvares-Solas , PNAS, 2011). We show here that an accelerated melting of Greenland ice sheet (GrIS) can indeed led to a more rapid sea level rise and associated costal damage, but also changes the African monsoon intensity and location during the 21st century. To account for these potential instabilities, we explore the impact of different scenarios of abrupt GrIS during the 21st century superimposed to RCP8,5. We will present the results of these freshwater housing experiments corresponding to a superimposed sea level rise varying from 0,5 to 3m. We demonstrate that such a melting led to major consequences on the West African monsoon: duration, delay and a decreasing of the precipitation. Moreover, we investigated the agricultural and health impact of these abrupt climate changes on the very sensitive Sahel region (Defrance, PNAS, 2017). First, we quantify the agricultural area losses due to monsoon changes. Consequently, we pinpoint a large potential for migration of millions of people in the coming decades. Thus, the ice-sheet destabilization provokes not only costal damages, but also large population migration in monsoon area. Secondly, the large changes of the hydrological cycle in tropical area may also provide favorable conditions for the spread of pathogens vectors. Using IPCC scenarios several studies have already shown the impact of climate changes as Malaria on extended areas.  Here we explore the potential risk due to the major atmospheric tropical reorganization due to ice sheet destabilization.