Scientists Agree on 30-Year Window of Opportunity to Prepare for Sea-Level Rise

A scientist observes the edge of an ice sheet. (Photo by Alex Rivest)

Research published in Nature, co-authored by Dartmouth Engineering Professor Hélène Seroussi and Professor of Earth Sciences Mathieu Morlighem, looks at the predictability of Antarctic ice loss and what this means for sea-level rise projections. 

The researchers have identified that a window of opportunity for climate action does exist. The next three decades represent a period of well-constrained sea level rise trajectories and are critical to strategic adaptation planning.

"This provides a firm basis for near-term planning, while highlighting priorities for model development aimed at resolving longer-term sea-level rise uncertainty," said Seroussi, who is leading the science team modeling the evolution of the Antarctic ice sheet for the seventh Ice Sheet Model Intercomparison Project.

Reports from the Intergovernmental Panel on Climate Change (IPCC) predict that the rate of sea-level rise from Antarctic ice loss alone could nearly double within the next 30 years. But until now, there has been no robust estimate of Antarctica's contribution to sea level rise over the next few decades, the timescale most critical for coastal planning and policy decisions.

"We find that the rate of mass change in all models, including the ones that lead to high rates of sea-level change, shows constant mass loss over the next 30 years," said Morlighem. "The fact that all models agree that the change in mass will not skyrocket over the next three decades was very unexpected. It is a new finding."

The research aims to answer the question of how much ice Antarctica will lose over the next 30–50 years, and whether that loss can be predicted reliably enough to give governments and nation states sufficient lead time to respond effectively. The study assessed predictability from a range of ice sheet model projections of sea-level rise within this near-term window.

Led by Monash University researcher Felicity McCormack, the study originally came out of a conference last summer on The Physics of Changing Polar Climate co-organized by Seroussi and Morlighem. "We were the only glaciologists in the group and processed all of the model output," said Morlighem.

He further explained, "Dartmouth was involved at each step: collecting model output from several ice sheet modeling groups worldwide, organizing a ten-week program on the physics of polar climate to brainstorm with other polar scientists, and co-discovering this very robust feature in model projections that we did not see coming."