Geography

Divergent trajectories of Antarctic surface melt under two twenty-first-century climate scenarios

Document Type

Article

Abstract

Ice shelves modulate Antarctic contributions to sea-level rise and thereby represent a critical, climate-sensitive interface between the Antarctic ice sheet and the global ocean. Following rapid atmospheric warming over the past decades, Antarctic Peninsula ice shelves have progressively retreated, at times catastrophically. This decay supports hypotheses of thermal limits of viability for ice shelves via surface melt forcing. Here we use a polar-adapted regional climate model and satellite observations to quantify the nonlinear relationship between surface melting and summer air temperature. Combining observations and multimodel simulations, we examine melt evolution and intensification before observed ice shelf collapse on the Antarctic Peninsula. We then assess the twenty-first-century evolution of surface melt across Antarctica under intermediate and high emissions climate scenarios. Our projections reveal a scenario-independent doubling of Antarctic-wide melt by 2050. Between 2050 and 2100, however, significant divergence in melt occurs between the two climate scenarios. Under the high emissions pathway by 2100, melt on several ice shelves approaches or surpasses intensities that have historically been associated with ice shelf collapse, at least on the northeast Antarctic Peninsula.

Publication Title

Nature Geoscience

Publication Date

2015

Volume

8

Issue

12

First Page

927

Last Page

932

ISSN

1752-0894

DOI

10.1038/ngeo2563

Keywords

air temperature, climate modeling, global ocean, ice sheet, ice shelf, ice-ocean interaction, sea level change, trajectory

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