A Reconciled Estimate of Ice-Sheet Mass Balance

By A. Shepherd, Erik Ivins, G. A, V. Barletta, Michael J. Bentley, Srinivas V. Bettadpur, K. Briggs, D. Bromwich, R. Forsberg, N. Galin and 37 more. Science, 2012

1,443 citations recorded by the source corpus.

Warming and Melting Mass loss from the ice sheets of Greenland and Antarctica account for a large fraction of global sea-level rise. Part of this loss is because of the effects of warmer air temperatures, and another because of the rising ocean temperatures to which they are being exposed. Joughin et al. (p. 1172) review how ocean-ice interactions are impacting ice sheets and discuss the possible ways that exposure of floating ice shelves and grounded ice margins are subject to the influences of warming ocean currents. Estimates of the mass balance of the ice sheets of Greenland and Antarctica have differed greatly—in some cases, not even agreeing about whether there is a net loss or a net gain—making it more difficult to project accurately future sea-level change. Shepherd et al. (p. 1183) combined data sets produced by satellite altimetry, interferometry, and gravimetry to construct a more robust ice-sheet mass balance for the period between 1992 and 2011. All major regions of the two ice sheets appear to be losing mass, except for East Antarctica. All told, mass loss from the polar ice sheets is contributing about 0.6 millimeters per year (roughly 20% of the total) to the current rate of global sea-level rise. The mass balance of the polar ice sheets is estimated by combining the results of existing independent techniques. We combined an ensemble of satellite altimetry, interferometry, and gravimetry data sets using common geographical regions, time intervals, and models of surface mass balance and glacial isostatic adjustment to estimate the mass balance of Earth’s polar ice sheets. We find that there is good agreement between different satellite methods—especially in Greenland and West Antarctica—and that combining satellite data sets leads to greater certainty. Between 1992 and 2011, the ice sheets of Greenland, East Antarctica, West Antarctica, and the Antarctic Peninsula changed in mass by –142 ± 49, +14 ± 43, –65 ± 26, and –20 ± 14 gigatonnes year−1, respectively. Since 1992, the polar ice sheets have contributed, on average, 0.59 ± 0.20 millimeter year−1 to the rate of global sea-level rise.

Subfields: Atmospheric Science, Oceanography, Pulmonary and Respiratory Medicine

View Paper: https://www.semanticscholar.org/paper/dee3a0eb391c4d18b9091a5489c941a95eff24b4

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Citations in the corpus

A roadmap for Antarctic and Southern Ocean science for the next two decades and beyond (2014, background): “However, an increasing imbalance in this mass budget has been observed in the past two decades, and the trend is accelerating (Joughin & Alley 2011, Rignot et al. 2011, Pritchard et al. 2012, Shepherd et al. 2012, Mouginot et al. 2014).”
Evolving Understanding of Antarctic Ice‐Sheet Physics and Ambiguity in Probabilistic Sea‐Level Projections (2017, background): “1 mm/yr, which is about a factor of 3 less than that currently observed for the early 21st-century (Church et al., 2013b; Harig & Simons, 2015; Shepherd et al., 2012).”
GIA Model Statistics for GRACE Hydrology, Cryosphere, and Ocean Science (2018, background): “…for decontaminating GRACE trends of GIA-related mass change when determining the ice sheet contribution to sea level rise (Ivins et al., 2013; Martín-Español et al., 2016; Sasgen et al., 2012; Shepherd et al., 2012) or to changes in the polar oceans (Morison et al., 2007; Ponte & Piecuch, 2014).”
Forty-six years of Greenland Ice Sheet mass balance from 1972 to 2018 (2019, methodology): “For 1992–2011, the 142 ± 49 Gt/y mass loss from multiple methods (41) is within errors of our 144 ± 13 Gt/y estimate.”