Study Says Antarctic Meltwater Feedback Could Add to 34 cm Sea-Level Rise by 2100
Updated
Updated · Earth.com · May 20
Study Says Antarctic Meltwater Feedback Could Add to 34 cm Sea-Level Rise by 2100
3 articles · Updated · Earth.com · May 20
Summary
Nature Geoscience research found Antarctic meltwater can alter ocean circulation in ways that accelerate further ice loss, a feedback loop the authors say most policy-shaping climate models do not include.
Fresh meltwater weakens the cold, dense barrier that normally blocks warmer deep-ocean currents from ice shelves, letting heat reach the ice base and intensify melting in a self-reinforcing cycle.
The effect is not uniform: in the Weddell Sea it amplifies melt, while in the West Antarctic Peninsula and Amundsen Sea upstream freshwater can briefly form a colder shield that slows local melting.
The IPCC now estimates Antarctic meltwater could add 28 to 34 centimeters of sea-level rise by 2100 under high-emissions scenarios, and the study argues those projections may be too low if these feedbacks prove large.
More than 680 million people live in low-lying coastal zones, and the team is building higher-resolution simulations through 2100 to identify which ice shelves may be closest to tipping points.