A thicker Antarctic ice stream during the mid-Pliocene warm period

• Published in: Communications Earth & Environment
• Main Authors: Martim Mas e Braga, Richard S. Jones, Jorge Bernales, Jane Lund Andersen, Ola Fredin, Mathieu Morlighem, Alexandria J. Koester, Nathaniel A. Lifton, Jonathan M. Harbor, Yusuke Suganuma, Neil F. Glasser, Irina Rogozhina, Arjen P. Stroeven
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Portfolio 2023
• Subjects: Geology; QE1-996.5; Environmental sciences; GE1-350; Antarctic; Dronning Maud Land; East Antarctica; Jutulstraumen; Antarc*; Antarctica; Ice Sheet; Ice Shelf
• Online Access: https://doi.org/10.1038/s43247-023-00983-3; https://doaj.org/article/c55f1988ac9d40979e2198fe032c0e41

Abstract Ice streams regulate most ice mass loss in Antarctica. Determining ice stream response to warmer conditions during the Pliocene could provide insights into their future behaviour, but this is hindered by a poor representation of subglacial topography in ice-sheet models. We address this limitation using a high-resolution model for Dronning Maud Land (East Antarctica). We show that contrary to dynamic thinning of the region’s ice streams following ice-shelf collapse, the largest ice stream, Jutulstraumen, thickens by 700 m despite lying on a retrograde bed slope. We attribute this counterintuitive thickening to a shallower Pliocene subglacial topography and inherent high lateral stresses at its flux gate. These conditions constrict ice drainage and, combined with increased snowfall, allow ice accumulation upstream. Similar stress balances and increased precipitation projections occur across 27% of present-day East Antarctica, and understanding how lateral stresses regulate ice-stream discharge is necessary for accurately assessing Antarctica’s future sea-level rise contribution.