The contribution of Humboldt Glacier, northern Greenland, to sea-level rise through 2100 constrained by recent observations of speedup and retreat

• Published in: The Cryosphere
• Main Authors: Hillebrand, Trevor R., Hoffman, Matthew J., Perego, Mauro, Price, Stephen F., Howat, Ian M.
• Format: Text
• Language: English
• Published: 2022
• Subjects: Greenland; glacier; Humboldt Glacier; Ice Sheet
• Online Access: https://doi.org/10.5194/tc-16-4679-2022; https://tc.copernicus.org/articles/16/4679/2022/

Humboldt Glacier, northern Greenland, has retreated and accelerated through the 21st century, raising concerns that it could be a significant contributor to future sea-level rise. We use a data-constrained ensemble of three-dimensional higher-order ice sheet model simulations to estimate the likely range of sea-level rise from the continued retreat of Humboldt Glacier. We first solve for basal traction using observed ice thickness, bed topography, and ice surface velocity from the year 2007 in a PDE-constrained (partial differential equation) optimization. Next, we impose calving rates to match mean observed retreat rates from winter 2007–2008 to winter 2017–2018 in a transient calibration of the exponent in the power-law basal friction relationship. We find that power-law exponents in the range of <math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">1</mn><mo>/</mo><mn mathvariant="normal">7</mn></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="20pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="29d80a96c1e485b2ea8e9894bab6fe24"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-16-4679-2022-ie00001.svg" width="20pt" height="14pt" src="tc-16-4679-2022-ie00001.png"/></svg:svg> – <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><mn mathvariant="normal">1</mn><mo>/</mo><mn mathvariant="normal">5</mn></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="20pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="215b47dca0c01018ce05fbe844dd5ae6"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-16-4679-2022-ie00002.svg" width="20pt" height="14pt" src="tc-16-4679-2022-ie00002.png"/></svg:svg> – rather than the commonly ...