A 21 st Century Warming Threshold for Sustained Greenland Ice Sheet Mass Loss

• Main Authors: Noël, B., van Kampenhout, L., Lenaerts, J. T. M., van de Berg, W. J., van den Broeke, M. R.
• Other Authors: Sub Dynamics Meteorology, Marine and Atmospheric Research
• Language: English
• Published: 2021
• Subjects: Greenland; Ice Sheet
• Online Access: https://dspace.library.uu.nl/handle/1874/411206

Under anticipated future warming, the Greenland ice sheet (GrIS) will pass a threshold when meltwater runoff exceeds the accumulation of snow, resulting in a negative surface mass balance (SMB < 0) and sustained mass loss. Here, we dynamically and statistically downscale the outputs of an Earth system model to 1 km resolution to infer that a Greenland near-surface atmospheric warming of 4.5 ± 0.3°C—relative to preindustrial—is required for GrIS SMB to become persistently negative. Climate models from CMIP5 and CMIP6 translate this regional temperature change to a global warming threshold of 2.7 ± 0.2°C. Under a high-end warming scenario, this threshold may be reached around 2055, while for a strong mitigation scenario it will likely not be passed. Depending on the emissions scenario taken, our method estimates 6–13 cm sea level rise from GrIS SMB by the year 2100.