Satellite record reveals 1960s acceleration of Totten Ice Shelf in East Antarctica

Wilkes Land and Totten Glacier (TG) in East Antarctica (EA) have been losing ice mass significantly since 1989. There is a lack of knowledge of long-term mass balance in the region which hinders the estimation of its contribution to global sea level rise. Here we show that this acceleration trend in TG has occurred since the 1960s. We reconstruct ice flow velocity fields of 1963-1989 in TG from the first-generation satellite images of ARGON and Landsat-1 & 4, and build a five decade-long record of ice dynamics. We find a persistent long-term ice discharge rate of 68 & PLUSMN; 1 Gt/y and an acceleration of 0.17 & PLUSMN; 0.02 Gt/y(2) from 1963 to 2018, making TG the greatest contributor to global sea level rise in EA. We attribute the long-term acceleration near grounding line from 1963 to 2018 to basal melting likely induced by warm modified Circumpolar Deep Water. The speed up in shelf front during 1973-1989 was caused by a large calving front retreat. As the current trend continues, intensified monitoring in the TG region is recommended in the next decades. Historical velocity maps reveal over five decade-long acceleration and high-level discharge in Totten Glacier, East Antarctica, from 1963-2018, induced by warm modified Circumpolar Deep Water.

Automated summary

Wilkes Land and Totten Glacier in East Antarctica have been experiencing significant ice loss since 1989. However, previous studies have not provided long-term data on ice mass balance, which hinders accurate estimation of its contribution to global sea level rise. In this study, we analyze satellite images from the 1960s to reconstruct ice flow and dynamics in Totten Glacier. Our findings reveal a consistent ice discharge rate and acceleration, indicating that Totten Glacier is the largest contributor to sea level rise in East Antarctica. We attribute this long-term acceleration to basal melting caused by warm modified Circumpolar Deep Water. The study highlights the need for intensified monitoring in the region to better understand and predict future changes.