Accelerating glacier volume loss on Juneau Icefield driven by hypsometry and melt-accelerating feedbacks

• Published in: Nature communications Vol. 15; no. 1; pp. 5099 - 19
• Main Authors: Davies, Bethan, McNabb, Robert, Bendle, Jacob, Carrivick, Jonathan, Ely, Jeremy, Holt, Tom, Markle, Bradley, McNeil, Christopher, Nicholson, Lindsey, Pelto, Mauri
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 02.07.2024; Nature Publishing Group; Nature Portfolio
• Subjects: 704/106/125; 704/106/694; Ablation; Glaciers; Humanities and Social Sciences; Hypsometry; Ice fields; Mass balance; multidisciplinary; Regrowth; Science; Science (multidisciplinary); Sea level rise; Thinning; United States > US; Alaska
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-49269-y

Globally, glaciers and icefields contribute significantly to sea level rise. Here we show that ice loss from Juneau Icefield, a plateau icefield in Alaska, accelerated after 2005 AD. Rates of area shrinkage were 5 times faster from 2015–2019 than from 1979–1990. Glacier volume loss remained fairly consistent (0.65–1.01 km 3 a −1 ) from 1770–1979 AD, rising to 3.08–3.72 km 3 a −1 from 1979–2010, and then doubling after 2010 AD, reaching 5.91 ± 0.80 km 3 a −1 (2010–2020). Thinning has become pervasive across the icefield plateau since 2005, accompanied by glacier recession and fragmentation. Rising equilibrium line altitudes and increasing ablation across the plateau has driven a series of hypsometrically controlled melt-accelerating feedbacks and resulted in the observed acceleration in mass loss. As glacier thinning on the plateau continues, a mass balance-elevation feedback is likely to inhibit future glacier regrowth, potentially pushing glaciers beyond a dynamic tipping point. The glaciers of Juneau Icefield, Alaska are reconstructed from 1770 to 2020 AD. Ice loss has accelerated dramatically, with a number of positive feedbacks now happening that accelerate ice loss and inhibit future stabilisation and regrowth.