Peak refreezing in the Greenland firn layer under future warming scenarios

Firn (compressed snow) covers approximately 90[Formula: see text] of the Greenland ice sheet (GrIS) and currently retains about half of rain and meltwater through refreezing, reducing runoff and subsequent mass loss. The loss of firn could mark a tipping point for sustained GrIS mass loss, since dec...

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Bibliographic Details
Published in:Nature Communications
Main Authors: Noël, Brice, Lenaerts, Jan T. M., Lipscomb, William H., Thayer-Calder, Katherine, van den Broeke, Michiel R.
Format: Text
Language:English
Published: Nature Publishing Group UK 2022
Subjects:
Online Access:http://www.ncbi.nlm.nih.gov/pmc/articles/PMC9652464/
http://www.ncbi.nlm.nih.gov/pubmed/36369265
https://doi.org/10.1038/s41467-022-34524-x
Description
Summary:Firn (compressed snow) covers approximately 90[Formula: see text] of the Greenland ice sheet (GrIS) and currently retains about half of rain and meltwater through refreezing, reducing runoff and subsequent mass loss. The loss of firn could mark a tipping point for sustained GrIS mass loss, since decades to centuries of cold summers would be required to rebuild the firn buffer. Here we estimate the warming required for GrIS firn to reach peak refreezing, using 51 climate simulations statistically downscaled to 1 km resolution, that project the long-term firn layer evolution under multiple emission scenarios (1850–2300). We predict that refreezing stabilises under low warming scenarios, whereas under extreme warming, refreezing could peak and permanently decline starting in southwest Greenland by 2100, and further expanding GrIS-wide in the early 22[Formula: see text] century. After passing this peak, the GrIS contribution to global sea level rise would increase over twenty-fold compared to the last three decades.