Our research has provided the first clear evidence that the Greenland Ice Sheet is not only melting rapidly at its surface but from the bottom up as well. Huge quantities of meltwater are produced every summer and when it descends to the bed – a kilometre or more below, energy is converted into heat in a process like the hydroelectric power generated by large dams. To study that effect, we recorded basal conditions in boreholes, while using phase-sensitive radio-echo sounding to measure the rate at which ice melts at the bottom of the glacier. The findings, published in the Proceedings of the National Academy of Sciences, show unexpectedly warm basal conditions and melt rates that that are approximately 100 times greater than expected. The research shed light on an over-looked ice-sheet mass-loss mechanism, which is not yet included in projections of global sea level rise.
Young, T. J., Christoffersen, P. et al. Rapid basal melting of the Greenland Ice Sheet from surface meltwater drainage, Proceedings of the National Academy of Sciences, 119 (10), 2022, doi:10.1073/pnas.2116036119