Ocean temperature impact on ice shelf extent in the eastern Antarctic Peninsula

Johan Etourneau,Hugues Goosse,Didier Swingedouw,Giovanni Sgubin,Xavier Crosta,Jung-Hyun Kim,Jaap S Sinninghe Damsté,Stefan Schouten,Guillaume Massé,Marie-Noëlle Houssais,Verónica Willmott,Loïc Barbara,Julien Crespin,Carlota Escutia

doi:10.1038/s41467-018-08195-6

Abstract

The recent thinning and retreat of Antarctic ice shelves has been attributed to both atmosphere and ocean warming. However, the lack of continuous, multi-year direct observations as well as limitations of climate and ice shelf models prevent a precise assessment on how the ocean forcing affects the fluctuations of a grounded and floating ice cap. Here we show that a +0.3–1.5 °C increase in subsurface ocean temperature (50–400 m) in the northeastern Antarctic Peninsula has driven to major collapse and recession of the regional ice shelf during both the instrumental period and the last 9000 years. Our projections following the representative concentration pathway 8.5 emission scenario from the Fifth Assessment Report of the Intergovernmental Panel on Climate Change reveal a +0.3 °C subsurface ocean temperature warming within the coming decades that will undoubtedly accelerate ice shelf melting, including the southernmost sector of the eastern Antarctic Peninsula.

Highlights

The recent thinning and retreat of Antarctic ice shelves has been attributed to both atmosphere and ocean warming
Our results suggest that the ocean thermal forcing, tied to the circulation of the relatively warm Warm Deep Water (WDW), has played a central role on the regional ice shelf instability during both the instrumental period and Holocene; a slight ocean warming contributing to substantial ice shelf collapse and regression
When extrapolating these results to the most pessimistic Intergovernmental Panel on Climate Change (IPCC) emission scenario, we show that a slight subsurface ocean warming will further accentuate the current erosion of the eastern Antarctic Peninsula (EAP) ice shelf by the end of the twentyfirst century

Summary

Introduction

The recent thinning and retreat of Antarctic ice shelves has been attributed to both atmosphere and ocean warming. Reanalyses[18,19] concomitantly document a sharp increase in subsurface ocean temperatures (SOT) (50–400 m water depth) on the continental shelf reaching up to +0.6 °C, sharing a similar pattern with the computed Ekman pumping during the same period of time.

Results

Conclusion