Key points
- Scientists reached the Denman Glacier in East Antarctica for the first time by ship, braving icy temperatures and strong winds to better understand the impacts of a warming climate on the region.
- It is one of the largest glaciers in East Antarctica, potentially causing global sea level to rise by 1.5 metres if it were to all melt.
- Autonomous and cutting-edge technologies are taking long-term measurements on ocean conditions surrounding the glacier to provide critical intel for managing future climate risk.
Imagine traversing icebergs the size of eight football fields on a 160-metre-long research vessel, while bracing 100 km/h winds in air temperatures reaching -36 degrees Celsius.
This was an average day for our scientist Dr Laura Herraiz Borreguero, who has recently returned from a two-month voyage on the Australian icebreaker, RSV Nuyina.
This is the first time researchers have comprehensively studied the glacier from the ocean, as part of the Denman Marine Voyage.
Laura’s role, in partnership with the Australian Antarctic Program Partnership (AAPP), was to take a deeper dive into ocean conditions surrounding the Denman glacier, and its likely contribution to global sea level rise in the coming decades. CSIRO also provided various other technical expertise, equipment and support, including deploying the Hydrobox on the voyage.
Why is the Denman Glacier so important?
“The Denman Glacier is one of the largest glaciers in East Antarctica,” said Laura.
“However, over the last two decades, its grounding line – which is the area where a glacier sits on bedrock – has retreated significantly and quickly.
“This means the Denman Glacier is vulnerable to rapid ice mass loss, resulting in thinner ice and larger ice discharge into the ocean.
“If it were to completely melt, it would increase global sea levels by 1.5 metres.”
As part of the voyage, Laura and the team wanted to find out how likely, and under what climate conditions, the glacier will lose ice mass rapidly.
Southern Ocean changes have global impacts
The Southern Ocean holds the fate of Antarctica, transporting warm water from the deep Southern Ocean to the base of ice shelves. But until now, we have had very limited ocean observations near the Denman Glacier.
"I suspect warmer waters coming up underneath the glacier – known as Circumpolar Deep Water – may have something to do with why it's melting,” said Laura.
“If this is the case, the Denman Glacier could contribute to sea level faster than previously thought, with changes being detected over decades, rather than centuries.”
Moorings and floats: technology to better understand the ocean
As part of this voyage, the team deployed a range of technologies to observe the climate system and track how it is evolving.
“To work in such a remote and hostile environment, we needed some very sturdy and cutting-edge equipment that could withstand wild ocean conditions and enhance data collection from the ship,” explained Laura.
Specifically designed moorings – engineered and built by our Engineering and Technology team – fit the bill.
“Moorings are long anchored lines of scientific equipment and floats which collect a range of ocean data such as temperature, salinity, and ocean currents,” said Laura.
“These data are collected over long periods, often one year or more.
“Two of our moorings are in the ocean right now about 30 km from the Denman Glacier, in the pathway of warm water towards the Denman.
“The moorings will continue measuring for up to two years.”
Thirteen Argo floats, which are robotic floats collecting data on ocean conditions, have also been deployed to take ongoing measurements up and down the water column. They are expected to give us insights into ocean conditions for months to years, to detect changes in temperature, pressure and salinity.
“When the Argos reach the ocean surface, they send the data – like a phone call – which we can access,” said Laura.
This data feeds into Australia's Integrated Marine Observing System.
Swelling our knowledge: what we know so far
Laura was confronted to see so little sea ice in the region, with up to 70 per cent less sea ice concentration captured in satellite images during the same time of year previously.
“The ocean observations collected over the last few months and beyond, will provide us with vital information to pinpoint what's driving the changes in the region, how likely they are to be sustained in the future, and what the impacts of those changes are on future global sea level, our climate and ecosystems across the world,” said Laura.
“More will be revealed once our extensive data is analysed.”
Cool collaboration: building Antarctic research capabilities
Laura led CSIRO’s oceanography research for the voyage and coordinated the multidisciplinary science led by the AAPP.
She was one of 60 scientists who joined the Denman Marine Voyage, which was a collaboration between the AAPP, the Australian Centre for Excellence in Antarctic Science (ACEAS), Securing Antarctica’s Environmental Future (SAEF) and the Australian Antarctic Division (AAD).