‘Potential to raise sea levels by 1.5 metres’

Glaciologist Dr Sarah Thompson, who’s affiliated with the AAPP and ACEAS, will spend eight weeks studying the stability of the Denman Glacier system, to better understand how sea levels will be affected if it melts.  

“The Denman system alone has the potential to raise sea levels by 1.5 metres and we know ice shelves can be vulnerable to a warming ocean,” Dr Thompson said.  

“The floating parts of these systems act like dams, they’re holding back ice on the continent, so if we start to break up or weaken that dam we’ll immediately bring a lot more ice from the continent into the ocean.

“It’s really important for us to know more about the stability and structure of these systems so we can better predict sea level rise, both in terms of the magnitude but also the timing of these events.”

‘The most change is happening at the interface between the ice and the ocean’

Dr Thompson will use geophysical instruments and radar to measure ice thickness, and seismic instruments to provide point measurements of the ocean bed.

“That will give us an idea of the thickness of the water column between the base of the ice and the ocean bed. That’s important because it allows us to predict where different currents might access the ice shelf.”

The glaciologist will also use a hot water drill to penetrate the glacier so ice and oceanographic instruments can be suspended through the ice and the ocean and retrieved next year.

“We think from other areas in Antarctica, changes may be happening at the interface between the ice and the ocean, at the base of some of these large ice shelves and glaciers.

"It is one of the most difficult places to observe and that's what we are really interested in looking at this field season,” Dr Thompson said.

A unique feature of the Denman Terrestrial Campaign is that the scientists come from a range of institutions and disciplines. 

“It means we'll learn so much about the system itself,” Dr Thompson said.  

“Some people are focussing on what happened a thousand years ago and that’s helping us understand what’s happening now. 

“There hasn't been much work done on this region before so there’s a lot of uncertainty about what the base of the glacier looks like.

“It’s also the most northerly system outside the Antarctic Peninsula so potentially it is more vulnerable to a warming climate than some of the other systems in East Antarctica.”

Weather a major challenge

There are challenges in conducting science experiments in an environment as remote as Bunger Hills.

The hot water drilling instruments have been used before but high winds and extremely low temperatures will put them to the test. 

The team will also have to melt up to 10,000 litres of water for every hole they drill.

Then there’s the weather.

(At the time of writing, flights from Hobart to the Wilkins Aerodrome, and from Casey to Bunger Hills, had already been delayed several times due to high winds and blizzards.)

As coordinating scientist, it will be Dr Souter’s job to manage expectations and decide which scientist goes where, on any given day. 

“The weather is going to be a significant challenge for us,” Dr Souter said.

“We’re very lucky in that we have a couple of operating helicopters.

“If the weather is fine we’ll get an awful lot of science done.

“If the weather is a challenging, we’ll be operating in a resource-constrained environment and we’ll have to work hard at prioritising the most impactful science on any given day and that will change over the course of the campaign." 

‘Significant implications for sea level rise’

It will take hundreds, if not thousands, of years for the Denman Glacier to melt.

But the impacts will be far-reaching.

“The glaciers of the East Antarctic region are significant in that they hold a huge amount of ice and if climate change happens as we think it’s going to, melting ice will have significant implications for sea level rise and for the broader Southern Ocean and even the climate of Australia,” Dr Souter said.

“Antarctica is so influential in regional weather and climate patterns and the health of the Southern Ocean itself, so this will help Australia as a nation plan for the impact of a changing Antarctic climate.”