New analysis of almost 30 years’ worth of scientific data on the melting of the Greenland Ice Sheet predicts global sea level rise of at least 10 centimetres by the end of the 21st Century, per global warming trends.
The estimates, which scientists warn are “conservative” given the powerful effects of changes in weather systems and possible ways of accelerating ice loss, are broadly consistent with recent predictions reported by the Intergovernmental Panel on Climate Change.
Professor Edward Hanna of the University of Lincoln, UK, led an international team involving Belgian, Danish, Swiss and American glaciologists and climatologists, including UGA professor and Franklin College associate dean Thomas Mote, in the new study that quantifies the response of the Greenland Ice Sheet to climate change. Their findings are published in the International Journal of Climatology. A media release from the University of Lincoln describes analysis.
The Greenland Ice Sheet is a giant reservoir of ice that contains enough water to ultimately raise global sea-level by seven metres.
The researchers provide an updated analysis of Greenland surface air temperature data for the last three decades through to 2019, focusing mainly on coastal weather stations but also analysing records from relatively long-running sites on the interior plateau of the ice sheet. They found that Greenland coastal regions warmed significantly by about 4.4 degrees Celsius (degC) in winter and 1.7 degC in summer from 1991 to 2019. Their work, combining Greenland temperature data with computer model output of ice-sheet mass balance for 1972 to 2018, shows that each 1degC of summer warming corresponds to some 91 billion tonnes per year of surface mass loss and 116 billion tonnes per year of total mass loss from the ice sheet.
The research team then used some of the latest available global and regional climate modelling tools to estimate that, under sustained strong global warming (a “business as usual” scenario), Greenland is likely to warm 4.0 to 6.6 degC by the year 2100. These recent and projected future Greenland warmings are considerably greater than global temperature changes for equivalent time periods, reflecting a high sensitivity of the polar regions to climate change.
The scientists then used the relation they derived between recent changes in Greenland summer temperature and surface mass balance to calculate a 10 to 12.5 centimetres increase in global sea-level rise by 2100 arising from increased Greenland ice melt and surface mass loss.
The research team very sadly notes the passing of their co-author Professor Konrad Steffen, who tragically died in an accident in Greenland on August 8. Prof. Steffen was a pioneer on Greenland Ice Sheet research, an early expert in the field and valued colleague whose work showed that climate change is melting Greenland’s vast ice sheet with increasing speed. We share our condolences on the loss of this extraordinary scientist.
Image: Margin of the Greenland ice sheet (view from plane). Courtesy of Alfred Wegener Institute for Polar and Marine Research vis Creative Commons.