Extended Data Table 1 Svalbard glacier changes, 1936-2010
From: Historical glacier change on Svalbard predicts doubling of mass loss by 2100
- The A2010 values are computed from the 2000-2010 Svalbard glacier inventory56, updated to include additional glaciers identified in the 1936 photogrammetric models (n = 220). The ±1σ error reported for V1936 is estimated by differencing the 1936 DEM to the 2008-2012 NPI reference DEM and computing the elevation differences over ice-free regions (see Methods). The reported ∆V error represents the uncertainty of the difference between the 1936 and 2010 surfaces (and thus the volume change during that interval) rather than the absolute volume uncertainty, which depends on the uncertainty of the bed topography59. The subaerial 1936-2010 mass change is computed using two simple models: 1) assuming that the removed glacier volume has a constant density57 of 850 ± 60 kg m−3, and 2) using a climatic mass balance and snowpack model5 to account for firn densification (Methods; Supplementary Information, Figs. S2-S4). The ‘subaq’ column tabulates the loss of grounded subaqueous ice, which does not contribute to sea level change (Supplementary Information, Fig. S5). Our estimated 1936-2010 rates of Svalbard-wide ice loss are comparable to the 2000-2019 rates estimated from ASTER DEMs (−10.5 ± 1.7 Gt yr−1)4 and less than the 2011-2017 rates estimated from CryoSat-2 (−16 ± 3.0 Gt yr−1)103 (Extended Data Fig. 1).
