Voice of the Sea Ice: A land of ice and ambition

10:21 am today

An aerial image looking down on a flat white expanse of ice with three vehicles towing long trailers of gear and small portable buildings. The front vehicle is carving a track parallel to the other two; both tracks extend from the bottom right corner into the middle of the white expanse.

Crossing the Ross Ice Shelf. Photo: Neil Silverwood

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Antarctica is a land of extremes - the coldest, the windiest, the driest - and arguably, the setting for the most epic journeys.

In the 'Heroic Age of Antarctic Exploration' 100 years ago, getting around involved dog sleds, ponies and man-hauling supplies across the ice. These were expeditions fraught with dangers: falling into a crack in the ice, getting lost in a storm, suffering from exposure and frostbite.

Today, the challenges of the extreme environment remain the same, but engineering and technological advancements have changed the game, opening new frontiers for science.

Three pyramidal tents on a flat expanse of white ice beneath a harsh sun and darkened sky. A lone figure walks between two tents.

Camping on the ice shelf. Photo: Neil Silverwood

Drilling back in time to learn about the future

One such scientific frontier: how the ice sheets are responding as the climate heats up.

This is the key question for the SWAIS2C project - an international collaboration, led by New Zealand agencies, attempting to drill through hundreds of metres of ice and into the seafloor sediment below.

The layers in this sought-after sediment are like a time machine. Scientists can use them to look back in time to 125,000 years ago, when global temperatures were 1-1.5°C warmer - similar to what the planet is heading towards now. What was the West Antarctic Ice Sheet like back then - did it fully melt away? Partially melt? And most importantly: what will this mean for us and future sea level rise?

A large half-cylinder tent next to a radio pole and an assortment of equipment.

The SWAIS2C team spent a month camped at the edge of the West Antarctic Ice Sheet, where it begins to float as the Ross Ice Shelf. Pictured is the drilling tent. Photo: Anthony Powell / Antarctica NZ

Antarctica's ice sheets are massive amounts of ice, kilometres thick, that sit on the continent's bedrock. As the ice sheets build up mass, they start to flow, ever so slowly, off the continent and down into the ocean. When they leave the land and start to float, they are called ice shelves.

The one closest to New Zealand's Scott Base is the largest: the Ross Ice Shelf.

The slowest road trip

"It's about the size of France and completely flat and completely white, and there is absolutely nothing to see."

Dr Daniel Price of the University of Canterbury and Kea Aerospace speaks from experience. He has crossed the Ross Ice Shelf several times in the past eight years.

A person abseiling down the side of an icy crevasse. A flat white expanse of ice extends as far as the eye can see. There are two orange road cones visible along the edge of the crevasse, and a line of flags on poles further in the distance.The sky is hazy and blue.

Checking crevasses. Photo: Daniel Price

The first time, in 2017, he was involved in finding the route for the SWAIS2C project's two drill sites. The first - at a point where West Antarctic Ice Sheet becomes Ross Ice Shelf - is a driving distance of 1300 km from Scott Base. Daniel was tasked with marking a safe path that dodged the biggest hazard: crevasses, or large cracks in the ice.

The initial part of the journey was along the South Pole Highway. The US Antarctic team maintain this route, using explosives to blow up and then fill in crevasses. But at some stage, Daniel needed to turn off the highway and venture out into the unknown.

A scene on an icy expanse with vehicle tracks indicated by flags on poles. An explosion in the distance seeds a cloud of snow and ice jetting into the air. A person crouches in the foreground with their back to the camera, watching the explosion.

South Pole highway remediation using explosives. Photo: Zoe Courville

This is where satellite images came in handy. Active microwave radar satellites bounce energy of the Earth's surface - a bit like an X-ray of the ice - revealing the cracks hidden beneath the snow.

But you can not rely solely on this X-ray image. Daniel also needed to check each crevasse on the ground, using a radar out the front of a vehicle like a minesweeper spotting crevasses in real-time.

This made their journey very slow. The vehicles travelled an average of 10 kilometres per hour in any non-crevassed areas, dropping to five or six kilometres per hour when surveying for crevasses.

A person in warm gear stands on the ice, wielding a large pole with a T-bar at the top. The person is pushing the pole into the ice. A vehicle with metal contraption attached to it is on the person's right. The scene is dark with grey light, as if the sun is blocked by a thick storm.

Checking for crevasses. Photo: Neil Silverwood

'Everything slows down'

Between the journey out and in, and work at the site, Daniel spent about 60 days on the Ross Ice Shelf each trip. Being in this flat, white expanse of nothing does something to your brain, he says.

"I guess it's kind of like muscles, if you don't use them - parts of the mind start to slow down and shut off. So when you come back to base or back to New Zealand, it's quite exhausting really to start interacting with people, seeing colours. And just the mind is a little overwhelmed for a while until it readjusts to the normalcy of life."

An aerial image looking down on the flat white expanse of an ice shelf, beneath a white sun and darkening indigo sky. Three vehicles, that look small from this height and angle, are traversing the expanse from left to right in a diagonal line.

Traversing the Ross Ice Shelf. Photo: Neil Silverwood

As for the aims of the SWAIS2C project, not everything has gone to plan. After many years of route-finding, capability building, logistics and planning, the team planned two 'shots' at actually drilling.

They successfully used hot water to drill through about 600 m of ice but ran into technical issues both years when trying to use their big drill rig system to get the coveted sediment cores.

In the first year they did retrieve some cores to study, albeit shallower than they had hoped. They will return next season to try again, at a different drill site.

This series was made with travel support from the Antarctica New Zealand Community Engagement Programme. Sign up to the Our Changing World monthly newsletter for episode backstories, science analysis and more.