A land of ice and ambition – podcast
RNZ science communicator Dr Claire Concannon introduces us to her Voice of the Sea Ice podcast series. She explains different types of ice and provides a glimpse into the past 'heroic age' of exploration of Antarctica.
Claire speaks to glaciologist Dr Daniel Price. Daniel leads work to mark out safe routes across the Ross Ice Shelf for science researchers to use. They explain various types of ice found in Antarctica, the dynamic nature of the moving ice sheets and why scientists are researching the ice sheets.
Jargon alert
Mass balance: How much ice an ice sheet gains or loses over time. It includes things like snowfall adding ice (accumulation) and melting or ice breaking off (ablation).
Notes of interest
At 6 minutes 40 seconds into the podcast, Dr Price explains the two types of radar technology used to look for crevasses in the ice. Why do you think they need to use two different approaches to identify crevasses?
The long-form version of this podcast is on the RNZ website here.
Transcript
Dr Claire Concannon
90 degrees south, the South Pole. Layer up because the wind is biting. The average temperature is about minus 60°C in winter, and minus 28 in summer. Your breath freezes in your buff, and tiny icicles form on your eyelashes.
Sunrise and sunset here are incredible, but there’s only one of each per year, so bad luck if there’s a storm. You have to choose your time to visit carefully. For 6 months of the year, the Sun never rises. In the other 6 months, under the light of the 24-hour Sun, you would see that you’re standing on a flat expanse of ice.
This is the East Antarctic Ice Sheet. And below your feet is over 2 kilometres of ice sitting on the bedrock of the Antarctic continent, enough to cover Mount Tongariro. This ice has accumulated over millions of years of snowfall.
Dr Daniel Price
Antarctica is actually very dry and classified as a desert, but the key thing is that, when it does snow, it stays. So the polar regions are very cold. And in our current climate, the snow sticks around and over a long time builds up into these colossal ice sheets. And colossal is the only word you can really use because they’re kilometres thick and cover vast, vast areas.
Dr Claire Concannon
This is Dr Daniel Price, a glaciologist at the University of Canterbury and chief scientist at the Christchurch company Kea Aerospace.
Dr Daniel Price
The ice sheet is split into two, the West Antarctic Ice Sheet, which is kind of the little brother, and then the East Antarctic Ice Sheet, which is the big brother.
Dr Claire Concannon
This eastern big brother has areas where the ice sheet is thicker than Aoraki Mount Cook is tall. The South Pole is on the East Antarctic Ice Sheet.
And in the time of Scott, Amundsen and Shackleton, what’s termed the 'heroic age' of Antarctic exploration in the early 20th century, there was … nothing.
Captain Robert Falcon Scott
Wednesday, January 17. The Pole. Yes, but under very different circumstances from those expected.
Dr Claire Concannon
This is an excerpt from Captain Robert Falcon Scott’s diaries on the day in 1912 that he and his party reached the South Pole – to find that Roald Amundsen had already been and gone just over a month before.
Captain Robert Falcon Scott
We started at 7.30, none of us having slept much after the shock of our discovery. The wind is blowing hard, T minus 21 Fahrenheit. And there is that curious, damp, cold feeling in the air, which chills one to the bone in no time. Great God! This is an awful place, terrible enough for us to have laboured to it without the reward of priority.
Dr Claire Concannon
In 1958, when Sir Edmund Hillary and his team reached the Pole in modified Massey Ferguson tractors, they weren’t that impressed either.
Sir Edmund Hillary
It was an anticlimax for me actually reaching the Pole. The big moment really was the last day, we just drove on and on and on. I think we did about 60 miles or something. Even I was having some doubts about our navigation because we had to find the Pole, you see, and sort of if we didn’t find it, it was going to be uncomfortable. But I remember then we saw something sort of just that was different. We got out the old binoculars and it was a flag, and actually it was a flag that the people at the American base, they had driven out and had planted this line of flags.
Dr Claire Concannon
Actually, Hillary wasn’t supposed to show up at the Pole at all. The plan was that the New Zealand team, led by Hillary, would support Dr Vivian Fuchs’ Trans-Antarctic Expedition. They were supposed to lay out some supply depots for Fuchs to use on the leg of the journey from the South Pole to Ross Island. But I guess after laying the last depot on the ice sheet, Hillary got so close he couldn’t help just popping by.
This trans-Antarctic expedition in 1957 and 58 coincided with a year dedicated to scientific exploration called the International Geophysical Year.
Leading up to this, to support both the scientific efforts and the expedition, New Zealand established a base on an island off the Antarctic continent called Ross Island. It was officially opened in January 1957 and named Scott Base.
A lot has changed since Scott’s time, but the ambition of some of the science projects and the wild background logistics needed to get the science going kind of match that heroic exploration vibe for me. Daniel’s been part of one of these crazy expeditions, not to the South Pole, but to a place on the Ross Ice Shelf, which is the next step in our getting to know Antarctica journey and the second type of ice I want to introduce you to.
Dr Daniel Price
All this ice of the ice sheet is up on the land, and as it accumulates mass and gets absolutely massive, under gravity, it flows towards the ocean, and as it flows towards the ocean and meets the ocean, it starts to float, and this is where you get your ice shelves.
Dr Claire Concannon
Ice shelves are generally hundreds of metres thick, so even though it’s floating on water, it’s still pretty darn solid feeling. There are 15 major ice shelves in Antarctica and many smaller ones. The Ross Ice Shelf is the biggest.
Dr Daniel Price
It’s about the size of France and completely flat and completely white, and there is absolutely nothing to see.
Dr Claire Concannon
Daniel was involved in finding a safe route for an ambitious science project that aims to drill through the ice shelf and then down into the seafloor below – but at a spot that’s a 1,300 kilometre drive from Scott Base. Seems easy enough?! The ice is hundreds of metres thick and mostly dead flat – or at least it looks that way right up until the point a thin crust of snow beneath you breaks away and you tumble down into a pitch dark icy canyon. You’ve met a crevasse.
Dr Daniel Price
It’s sort of the interaction of ice that’s moving at different speeds that creates these crevasses. You can kind of imagine putting the two palms of your hands on top of a big block of 1 kg cheese and pushing them in the opposite directions, and you get sort of cracking down the middle perhaps. That’s what we’re kind of talking about with the crevassing, and a lot of it’s hidden.
Dr Claire Concannon
Because different parts of the ice shelf are moving at different speeds, you get these zones that are rich in crevasses.
Dr Daniel Price
And that’s where we have to look to technology to help us out, to find out where the crevasses are, to make sure that they’re … one, we try to avoid them, and two, if we have to cross them, we want to make sure they’re safe to cross.
There are some pretty cool satellite technologies that are out there now. These are called active microwave radar satellites, and they essentially fire a chunk of energy at the Earth’s surface, and it hits the surface, interacts with it and comes back all at the speed of light. And it reveals, like an X-ray, the crevasses hidden below the surface, which is an incredibly useful tool for us.
Dr Claire Concannon
But it’s not enough to draw a line on this X-ray image of the crevasses and kind of hope that it’s all right. You’ve got to check it on the ground too using another radar.
Dr Daniel Price
You can kind of think of this as a minesweeper on the front of the vehicle that’s looking down in real time, and we have a screen in the vehicle, so someone’s driving and someone’s watching the screen, and in real time, it’s revealing in front of us if crevasses are coming up, and we use that with the satellite to get a really good idea or situational awareness of what’s happening around us. And day to day, it comes down to assessing individual crevasses as we move through crevasse fields to make a call as to whether we can keep going.
Dr Claire Concannon
So the drive at an average of 10 kilometres per hour takes about 2 weeks, and then they’ll set up a science camp or test equipment before driving back – a total of about 60 days.
Dr Daniel Price
Which can take a bit of a mental toll because there’s just so little mental stimulation visually. It’s a long time to be out there. Flat and white to the horizon is kind of the only way to explain it because it literally is what it is.
Dr Claire Concannon
Both Scott and Amundsen crossed the Ross Ice Shelf to get to the South Pole via different routes. Amundsen made it back, but it became Scott and his two remaining team members Wilson and Bowers’ final resting place. Here’s Sir Charles Wright, one of the team that found Scott’s last camp, talking about what will happen to their bodies.
Sir Charles Wright
They will be frozen, they will be imperishable, and either come out on the face of the Barrier Glacier in some hundreds of years or else into the sea at the foot of the Barrier if the ice melts from underneath.
Dr Claire Concannon
This is because, while the Ross Ice Shelf feels permanent, it’s just not.
Dr Daniel Price
Ice is lost either by calving at the edge of the ice shelves where icebergs break off or by basal melting from underneath. And these are the two processes we’re really interested in monitoring because Antarctica and other ice sheets and glaciers, their presence is all dictated by what’s called mass balance – so the amount of essentially snow coming in and then the amount of ice leaving at the peripheries by melting or calving. And this is the key thing to the global community because if it’s in a negative mass balance, sea level is rising.
Dr Claire Concannon
Ice shelves don’t contribute directly to sea-level rise when they melt because they’re already floating in water. But they buttress the glaciers and ice sheets behind them. And there’s a lot of ice in Antarctica.
Dr Daniel Price
It holds about 65 metres of sea level equivalent. So that were to all to melt, ocean levels would rise by that much. No one’s saying that’s going to happen in the short term, but even a metre of sea-level rise is a big, big, big problem for society.
Dr Claire Concannon
But there’s a third kind of ice, the star of our series. It’s time to introduce you to sea ice.
Dr Daniel Price
Once we get to the periphery of the ice shelves there, we reach the open ocean and the sea ice grows during the winter. The temperatures drop so far over the Southern Ocean that the water freezes. So this is the key difference between ice sheet and ice shelf and sea ice is that the sea ice is frozen seawater.
And there are many interactions between the continental ice, so the grounded ice and the ice shelves and the sea ice, that all play into some of these positive and negative feedbacks that are very complicated to understand in the Southern Ocean. And that’s another major part of research in Antarctica is trying to understand the interaction between the two and also to understand the changes to the sea ice regime.
Dr Claire Concannon
The annual freezing and melting, the expansion and contraction of sea ice, has been described by some as Antarctica’s heartbeat. And through its impacts on the Southern Ocean, this pulse is felt across the globe.
Dr Inga Smith
I’m standing on 2 metres of ice, and under that is the ocean – it goes off and connects the whole planet. Yeah, so it is kind of mind blowing.
Dr Claire Concannon
Next time on Voice of the Sea Ice, we learn about the importance of this beating heart and meet some of the researchers helping us understand the role it plays in our lives.
Thanks to Dr Daniel Price of the University of Canterbury and Kea Aerospace. Reporting for the series was supported by Antarctica New Zealand, with special thanks to Megan Nicholl for her help on the ice. Production help was from Ellen Rykers, editing by William Ray, sound design and engineering by William Saunders, with additional sound design by Steve Burridge.
Thanks to Ngā Taonga Sound and Vision for RNZ archival audio used in this episode.
I’m Claire Concannon. Have a great week. Kia pai, te wiki.
Acknowledgements
This podcast is courtesy of RNZ. It is from the Voice of the Sea Ice series by Dr Claire Concannon. The series was made with travel support from the Antarctica New Zealand Community Engagement Programme.
Dr Daniel Price, University of Canterbury and Kea Aerospace
Ngā Taonga Sound and Vision archival audio
