Global and monthly glacier mass balance from radar altimetry from 2010 to 2020

Abstract

<p>Glaciers are currently experiencing the largest land-ice imbalance and are the largest contributor to sea level rise after ocean thermal expansion, contributing ~30% to sea level budget. Global monitoring of these regions remains a challenging task since global estimates rely on a variety of observations and models to achieve the required spatial and temporal coverage, and significant differences remain between current estimates. Here we report, for the first time, the application of radar altimetry to retrieve spatially and temporally resolved elevation and mass changes of glaciers on a global scale. We apply interferometric swath altimetry to CryoSat-2 data acquired between 2010 and 2020 over all large mountain glacier regions and provide monthly and annual time series of glacier mass loss for each region, together with linear mass losses. We report ubiquitous and sustained ice loss ranging from 82.3 ± 6.3 Gt yr<sup>−1</sup> in Alaska, to 3.4 ± 2.5 Gt yr<sup>−1</sup> for the Antarctica Periphery. While there is a considerable spatial and temporal variability in imbalance, reflecting the complexity of regional atmospheric and oceanic forcing and of glacier forcing, the global glacier trend is remarkably sustained over this period. Globally, glaciers have lost a combined mean of 275 ± 15 Gt yr<sup>−1</sup> between 2010 and 2020 contributing 0.76 ± 0.5 mm yr<sup>−1 </sup>to global Sea Level Rise.</p>