Sustained ocean cooling insufficient to reverse sea level rise from Antarctica

As rising global emissions cause the atmosphere and oceans to warm, the Antarctic ice sheet edges closer to an unknown critical threshold for future unstable retreat. This has implications for the future of global sea level rise.

The Amundsen Sea Embayment in West Antarctica is a critical region for present and future ice loss, however most studies consider only a worst-case future for the region.

Can ice loss from the region be limited?

A team of researchers recently explored this question, using ice sheet model sensitivity experiments. They investigated the centennial scale implications of short-term periods of enhanced ocean driven sub-ice shelf melting on ice loss, and assessed what future reduction in melting is necessary to mitigate ice stream retreat and offset global sea level rise.

The study found that minimising ocean-driven melting through reduced emissions or geoengineering is essential to prevent serious future sea level rise.

Key findings include:

1. Short-term periods of large increases in melting can have the same long-term sea level effect as longer periods of small increases in melting.
2. Restoring elevated melt rates to present-day levels within 100 years causes rates of ice discharge to immediately decline, thereby limiting the overall sea level contribution from the region.
3. Substantially reducing melt rates below present-day for over a century does result in the re-advance of ice stream grounding lines, but fails to offset the total ice loss during this time.
4. While ice stream re-advance and slowed ice discharge is possible with reduced basal melting, a centennial scale increase in accumulation must occur to offset the extensive ice loss.

Read the paper here for more information.