| Summary: | Totten Glacier is the principal source of ice loss from the East Antarctic Ice Sheet. Although the East Antarctic Ice Sheet as a whole has remained approximately in balance, the response of Totten Glacier to climate forcing remains a key source of uncertainty in predicting its future contribution to sea level rise. Here, we compare and combine estimates of the mass change of Totten Glacier and it's surrounding region from satellite measurements of changes in its volume, ice speed and gravitational potential acquired over the past two decades between 2002 and 2022. Ice losses from the Totten Glacier catchment and two surrounding areas – the Vincennes Bay region and the Moscow University catchment – have doubled since 2002 from 8.5 ± 0.7 Gt/yr to 20 ± 1.5 Gt/yr. We find the largest disagreement in Vincennes Bay, which remains a challenging region in which to monitor mass changes - likely a combination of a paucity in observations of ice thickness, and the regions’ small mass imbalance compared to local SMB fluctuations. Using a regional climate model, we show that only Totten Glacier is losing ice due to it flowing faster than it’s equilibrium state, although the rate of its dynamic ice loss has slowed by 60 %. In total, the region has lost 285 ± 19 Gt of ice and raised the global sea level by 0.8 ± 0.1 mm, with the majority (62 %) of this loss originating from Totten Glacier itself.
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