The Cryosphere, 27 July 2023
A new process currently missing from climate models could increase sea level contributions from the Greenland Ice Sheet by up to 14% under our current high emissions pathway. Climate change increases the frequency of “anticyclones” (high-pressure systems) getting stuck over the Greenland Ice Sheet — leading to extreme melt events especially in summer, with near-24-hour strong sunlight given cloud-free conditions. Greenland has been subject to multiple extreme melt events in the past decade. For example, in 2012 a stationary area of high pressure over Greenland in July caused 98.6% of the ice sheet’s surface area to experience melt conditions, including the 3000-meter-high summit which typically remains well below freezing, invulnerable to melting even in summer. Today, observed ice losses from Greenland are already greater than even the worse-case projections of the latest Intergovernmental Panel on Climate Change (IPCC AR6) report. If today’s high emissions continue, this study indicates that sea-level rise from Greenland alone could reach 0.3 meters by 2100, and up to 3.7 meters by 2300.