More knowledge on the complexity of ice sheets will improve calculations of future sea-level rises

There is considerable uncertainty about how much the sea levels in the world’s oceans will rise in the future – both in the short and long term.

This uncertainty is problematic, since governments around the world need to prepare for rising sea levels – but how should they prepare?

The current models used to calculate future sea-level rises are flawed, especially in considering the contribution from the world’s massive ice sheets in Greenland and Antarctica.

The Novo Nordisk Foundation has just awarded two Challenge Programme grants totalling DKK 78.8 million, both of which will enable the development of more precise models of the ice sheets and how they will contribute to sea-level rises. One grant recipient is Christine Schøtt Hvidberg, Professor, Niels Bohr Institute, University of Copenhagen, who is receiving nearly DKK 42 million.

Christine Schøtt Hvidberg and her research colleagues will use the grant to reduce the uncertainty in the model projections so that the models can more accurately predict whether sea levels in the world’s oceans will rise by 30 centimetres or more than 100 centimetres by 2100.

“The models we use today are too simple and very uncertain. They are not up to date, and they fail to consider many of the dynamics and mechanisms of the ice sheets. In addition, we cannot yet predict precisely how much the global temperature needs to rise to experience the catastrophic scenario of an actual collapse of an ice sheet,” explains Christine Schøtt Hvidberg.

Ice sheets are not simply massive blocks of ice

The current models of the ice sheets do not really consider that the ice sheets are more than just massive blocks of ice.

The ice sheets are dynamic, with varying material properties and can be either porous or solid.

The ice sheets also have huge fissures and crevasses that affect how they slide over the bedrock, whether they can break off and float out to sea and how rapidly they melt. One fear is that huge pieces of the Antarctic ice sheet could break off and melt and cause a sudden large rise in the sea level.

When the future climate becomes warmer and more extreme, these varying material properties may more strongly affect how rapidly the world’s ice sheets melt and thus raise the sea level.

“The Greenland ice sheet may also retreat behind mountain peaks, which can affect how rapidly it melts, and a warmer climate means more precipitation and therefore also potentially more snowfall. All these factors require more advanced models than the current ones to be able to calculate the effects of these dynamics and how they influence the sea level in the world’s oceans,” says Christine Schøtt Hvidberg.

Will collect new data

In the 6-year research project, the researchers will develop and improve models for how the ice sheets contribute to raising the sea level in the world’s oceans.

They will achieve this by harnessing existing data and by collecting their own data by monitoring the movements of the ice sheets and precipitation amounts through both satellites and field work in Greenland.

Christine Schøtt Hvidberg has therefore assembled a team of researchers with many competencies – including ice sheet researchers, experts in theoretical fluid models, experts in climate modelling, statisticians and researchers in artificial intelligence. In addition to the group from the University of Copenhagen, the team also comprises researchers from the Danish Meteorological Institute and Northumbria University in Newcastle upon Tyne, United Kingdom.

“Our project is unique because we cover the entire chain from data collection and monitoring the ice sheets to theoretical modelling. The final goal is to provide more robust forecasts of the sea level that include the risk of a sudden collapse of an ice sheet, instability in the ice sheets and the effects of the contact between the ice sheets, the sea and the atmosphere,” explains Christine Schøtt Hvidberg.