NCI partners, the Antarctic Climate and Ecosystems Cooperative Research Centre (ACE CRC), are scaling up their models on Raijin to investigate sea level rise.

"The largest uncertainty in predictions of future sea level rise comes from a lack of understanding of how the Antarctic ice sheet will respond to climate change," explains project co-leader Dr Ben Galton-Fenzi.

"The current hypothesis is that the accelerated thinning we've been seeing, for example in the Totten Glacier region, is due to increased basal melting by a warmer ocean."

Initially, the team used time on Raijin allocated through the National Computational Merit Allocation Scheme to develop models to study the processes behind this phenomenon at 2 or 3 km resolution.

However, the time had come to ramp up the models' resolving power.

The team are currently developing an ocean model to cover the entire Antarctic continental ice shelf at 1 km resolution – a step that has substantially increased their requirement for computing resources.

"We'd seen more and more evidence in the literature suggesting that if you're going to do this properly you've got to be running models with at least 1 km resolution," says Dr Galton-Fenzi.

"We're at the stage now where we requires an order of magnitude increase in CPU hours compared to our regional-scale models.

"The best way to access those resources was to become an official NCI partner."

The end goal of the work is to collaborate with NCI's expert code optimisation team to couple the ocean model to an ice sheet model to look directly at how changes in the ocean lead to changes in the ice sheet.

The project is a consortium between the Australian Antarctic Division, the Antarctic Gateway Partnership, and ACE CRC.

As the largest reservoir of ice on Earth, melting of the Antarctic ice sheet could have severe implications for the world's major cities, says Dr Galton-Fenzi.

"We're really unsure of how the ice sheet will respond to climate changes and how much potential sea level rise could come from them. There's a big risk to coastal infrastructure, where you have expensive ports and where most of the world's population lives.

"Our research is focused on getting an upper bound prediction of sea level rise for the next hundred or two hundred years."