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

• Published in: Geophysical Research Letters
• Main Authors: Noël, Brice, van Kampenhout, L., Lenaerts, J.T.M., van de Berg, W.J., van den Broeke, M.R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Blackwell Publishing Ltd 2021
• Subjects: CESM2; future; Greenland; regional climate model; surface mass balance; Atmospheric warming; Earth system model; Emissions scenarios; Greenland Ice Sheet; Pre-industrial; Sea level rise; Temperature changes; Geophysics; Earth and Planetary Sciences (all); General Earth and Planetary Sciences; Physical; chemical; mathematical & earth Sciences; Earth sciences & physical geography; Physique; chimie; mathématiques & sciences de la terre; Sciences de la terre & géographie physique; Ice Sheet
• Online Access: https://orbi.uliege.be/handle/2268/301943; https://orbi.uliege.be/bitstream/2268/301943/1/Noel_2020_GRL.pdf; https://doi.org/10.1029/2020GL090471

peer reviewed 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.