Study of ice-flow physics will improve predictions of ice sheet movement

A University of Otago – Ōtākou Whakaihu Waka-led study is developing innovative methods to accurately predict how ice sheets and glaciers are deforming and moving.

Just published in the journal Nature Geoscience, the study is supported by The Royal Society Te Apārangi Marsden Fund and Antarctica New Zealand, and features researchers from the Universities of Cambridge, Pennsylvania and Maryland.

It investigates ice deformation – a key process in the movement of glaciers and ice sheets, that has been significantly impacted by climate change.

Warmer ocean temperatures make ice sheets thinner at the edges so that ice and meltwater enter the ocean, which makes the sea level rise.

Lead author Dr Sheng Fan, of Otago’s Department of Geology, says being able to estimate sea level rise is important to protect communities from flooding and plan for coastal erosion.

“One of the key parts of how scientists do this is based on a model called flow law, a mathematical equation that describes the physics of how ice flows,” Dr Fan says.

There are currently two commonly used flow laws, but they do not capture the full complexity of ice behaviours.

“We need a more precise flow law so we can reduce prediction errors, especially with the way climate change is progressing.”

Researchers gathered 70 years’ worth of data from experiments around the world – including New Zealand, the United Kingdom, the United States, Australia and France – to form a detailed data base.

The research used advanced statistical methods that account for uncertainties and limitations of previous ice-flow models, enabling more reliable predictions about future ice-sheet movement.

Professor David Prior, of the Department of Geology, says the study is significant.

“There are lots of things that contribute to sea level rise and the future of the ice sheet is probably the biggest uncertainty,” Professor Prior says.

“This study illustrates that we need to describe the behaviour of the ice much more precisely, particularly if we want to use ice sheet modelling as a predicting tool.

“If we want our predictions of ice movement over the next few decades to be robust, we need to get the physics right.”