Newfound ice sheet tipping point could cause greater sea level rise

A newly identified tipping point for the loss of ice sheets in Antarctica and elsewhere could mean future sea level rise is significantly higher than shown by current projections.

- Damian Carrington

A new study has examined how warming seawater intrudes between coastal ice sheets and the ground they rest on. The warm water melts cavities in the ice, allowing more water to flow in, expanding the cavities further in a feedback loop. This water then lubricates the collapse of ice into the ocean, pushing up sea levels.

The researchers used computer models to show that a "very small increase" in the temperature of the intruding water could lead to a "very big increase" in the loss of ice - the tipping point behaviour.

It is unknown how close the tipping point is, or whether it has already been crossed. However, the researchers said it could be triggered by temperature rises of just 10ths of a degree, and very likely by the rises expected in the coming decades.

Sea level rise is the greatest longterm impact of the climate crisis and is set to redraw the world map in the coming centuries. It has the potential to put scores of large cities, from New York City to Shanghai, below sea level and to affect billions of people.