The million year ice project: the quest to find the oldest ice on Earth

The photo that pops up with his periodic tweets is something of a non sequitur. Joel Pedro – “Lead Project Scientist, Million Year Ice Core Project, Australian Antarctic Division” – sits at the wheel of a Massey Ferguson tractor that’s seen better days, flannel shirt sleeves rolled to the elbow. Behind him there’s a glimpse of pale acres of rye grass – fodder for cattle grazed on his late grandmother’s property in Walpole, on the Western Australian south coast.

Click through to his profile and the farmyard shot is juxtaposed with one rather more in keeping with his polar credentials. Here he’s perched on the wide tracks of a beast of an all-terrain vehicle in a dazzling icescape. Swaddled in a goose-down jacket, he’s smiling broadly behind a frosty beard and wraparound shades.

The two photographs riff on a remarkable journey – from tractor to polar tracks, third-generation farmer to glaciologist. It would seem fair to characterise this as an unlikely life trajectory. But google Pedro’s home-town, and the tourist hyperbole would imply it was destiny. “North Pole, South Pole, WALPOLE!” Still, what are the odds?

‘North Pole, South Pole, Walpole!’ Antarctic researcher Joel Pedro on a tractor on his family’s Western Australian farm

Conjuring a little more synchronicity, it’s worth observing that the fortunes of Pedro’s settler-farmer forebears were always at the whim of weather. He grew up through an era of declining winter rainfall across the region. And as is now understood – thanks to the work of the same glaciologists whose ranks he’s joined – these conditions are entwined with mighty forces stretching across the Southern Ocean and deep into the ice. When circulating winds send moist, warm air down to East Antarctica – delivering higher snowfall to the coast near Casey station – they tend to cycle back dry, cool air and create drought in south-west Australia. Ice core records indicate this strengthening pattern is likely not a natural event but a consequence of human influence on the climate.

And this is the business Pedro has found himself in, extracting relics of history from the ice, “these really tightly connected components of the climate system – temperature, carbon dioxide, sea ice, ocean circulation – all so exquisitely and tightly linked together,” Pedro explains. “It’s something that comes out of paleoclimate science in general. The closer you look, the more everything is linked together. And it only takes quite small changes to trigger cascading things.”

As an undergraduate at the University of Western Australia, he “teetered on the brink of working on the salinity problem in WA”. But at 41, Pedro belongs to a generation weaned on warnings about rising temperatures.

In his lifetime, levels of atmospheric carbon have skyrocketed. A fascination with atmospheric chemistry – “not so much the white-lab-coat chemistry … rather the more adventurous side of it” – prompted Pedro to apply on spec to the Australian Antarctic Division (A) for some postgrad work. “They were looking for someone to work on reconstructing solar activity from ice cores using a cosmogenic isotope. And I kind of knew nothing about that, but thought it sounded pretty cool.”

Pedro drove his panel van across the Nullarbor, and 20 years and a few twists and turns later, he’s leading Australia’s full-throttle return to deep-field Antarctic science, heading its most ambitious and costly over-snow expedition in a generation. The objective is to set up a camp in the high interior of the East Antarctic Ice Sheet and drill a hole almost 3km deep. Over the next several summers, the crew will return to extract, catalogue and preserve three-metre lengths of glacial ice laid down over a million years, pushing through the moment when something cranky, dramatic and mysterious happened. Entrenched rhythms in and out of ice ages blew out, catapulting the planet into a profoundly different state.

Understanding just what happened way back then promises critical clues about conditions of life on the next Earth, the one human emissions are now conjuring into an ever-spiralling reality.

“What we’re trying to do here is understand where the tipping points are in the climate system,” says Pedro. What was going on in the atmosphere in the past, in particular with greenhouse gas levels? What was the solar story?

If we have this information, he says, “then we have a firm handle on these guardrails of where the climate system is stable and where it tips. And obviously what we’re looking at for the future is how far we can push the climate system before it tips into another state.”

Australia’s million-year ice core project is unequivocally a mission of discovery, and an urgent one. But the optics are also unambiguously strategic as Australia muscles up its Antarctic credentials and influence. The revival of the A’s long-mothballed deep traverse capability – the equipment, logistics and skills necessary to operate long-haul expeditions on the ice – is just part of a multibillion-dollar polar science program which, when it was signed off by Canberra in 2016, emphasised its service to the national interest and international relations.

A mission of discovery: the million year ice core project traverse convoy. Photograph: Nicole Webster/Australian Antarctic Division

China is right now also busy drilling for the prize of oldest ice, as are Europe and Japan. Russia is in the game, and South Korea has plans. Australia’s program, 15 years in the making, has long been at the forefront, but Pedro’s team has been delayed for two precious summer seasons by the global pandemic and poor luck with the weather. Any of these programs may stall or pull up short. But the hope is that at least a couple of them will retrieve the oldest ice in the next few years – more than one being ideal, to validate and replicate findings.

A million years to go, and no time to lose.

The ice age question

We’ve known since late last century, from marine sediment cores, that from three million years ago until about a million years ago, the Earth swung in and out of ice ages like clockwork, each cycle lasting around 41,000 years. And this fitted sweetly with the century-old hypothesis of Serbian scientist Milutin Milankovitch, who calculated that ice ages would occur every 41,000 years based on the tilt of the Earth’s axis of rotation as it travels around the sun. Then the cycle changed, and by 800,000 years ago it had blown out to a new pattern of 100,000 years.

This fits with another cycle described by Milankovitch, tracking changes in the shape of the Earth’s orbit over time from nearly circular to slightly elliptical. The planet was now dancing to a different, slower tune, as if someone had dialled the turntable down from 45 to 33 rpm. “It’s really worrying as a scientist when you realise you could have a perfectly good explanation for either [cycle], but you can’t explain why it would change,” says glaciologist Tas van Ommen, the A’s climate program leader and co-chair of the International Partnership in Ice Core Sciences (IPICS).

“That is the massive question behind the million year ice core.”

‘We’re coming for you, old ice!’

When I first interviewed Pedro it was mid-December 2021 and he was locked up in a Hobart hotel for 16 days of quarantine – the protocol for all A expeditioners in the time of Covid. From here he made the heart-in-mouth call on the final coordinates for the drill site at Dome C – 122.5209 E, 75.34132 S. It was the culmination of years of scoping and surveys, the end of a process Van Ommen was beginning back when Pedro was his PhD student. By now it was narrowed down to a question of metres, informed by intimate scrutiny of the underlying bedrock to identify the “sweet spot” most likely to yield the prize of oldest ice. “And I was sitting here in this room and shouting [through the email] were the lead ops guys.” The French crew at Concordia station was helping get some of the Australian equipment on site. “They needed our coordinates to drop off our bore-hole casings. I’m writing ‘guys, do we need to buy more time?’”

But time – this season – was up.

On 17 December 2021, Pedro tweeted with excitement: “We’re coming for you old ice … just boarded flight Antarctica’s Wilkins Aerodrome to join the first field season of @AusAntarctic @MillionYearIce project … busting to get on the ice and get out to Little Dome C with the team.” The core team waited at Casey for seven weeks for all the stars to align, always a high-stakes business given the variables and extremities of this place. In the end a combination of poor weather, limited operational windows and Covid scares at other bases thwarted any prospect of starting the drill for another year.

Joel Pedro during the million year ice core team’s part-training, part-consolation visit to Law Dome last summer. Photograph: Etienne Gros

‘It can feel like walking off a cliff’

I put it to Pedro that it’s more than the degrees of cold and the isolation that make the search for oldest ice daunting. It’s the idea that you are on the absolute frontline at this seismic moment of understanding around the Earth system, and our influence and our future. It must be like blasting into space on the nose of a rocket. How do you manage that knowledge, that burden?

“It can feel like walking off a cliff,” says Pedro. “If you engage with it too deeply it can be consuming, and I think even counterproductive.” Time with his kids, aged three and five, has helped, and his partner is also a scientist, an oceanographer. “It’s a bit frightening when you think that in the space of my lifetime, carbon dioxide levels in the atmosphere have changed as much as they do between a glacial and interglacial” – between ice age cycles of ice advancing and retreating. We’re talking about a temperature change of 6C that “just transforms the planet – changes sea levels by 120 metres”.

“And then you see that the pace of change is now 100 to 1,000 times faster than those natural changes. It’s just so bloody obvious – we can measure this in the carbon dioxide data, when you look at the isotopes. It’s clearly fossil-fuel burning. And then you see the state of some of the public and political debate, and that’s a big worry. And it has been that way for too long now.”

Returning to Hobart without having made it to Dome C last summer, Pedro was disappointed but pragmatic. “It kind of comes with the territory down there. It’s a five-year project – we just don’t want too many years like this.” The European oldest ice project – Beyond EPICA – has now completed its pilot drilling at Dome C and has the advantage of a nearby station, Concordia, and a well-established traverse capability. They’d be a strong bet to be the first to retrieve oldest ice, earning some pretty substantial scientific bragging rights.

‘We need to do things at our pace and to distinguish ourselves on the science side’: Australian equipment at Law Dome. Photograph: Nicole Webster/Australian Antarctic Division

But that won’t be the end of the story. At least one more core will be needed to verify the first, to be sure that what’s discovered is not some quirk or anomaly. “This underlines why it’s certainly not in our interest to try to make it a race,” says Pedro. “The thing I’m going to be pushing is that we need to do things at our pace, do things well and sensibly, and to distinguish ourselves on the science side.”

When the million year core team made their part-training, part-consolation visit to Law Dome last summer, Pedro writes me in an email, they turned off the diesel generator for a while, so they could listen to the silence. “We all sat outside then for some time and got kind of recharged by the vastness and the silence. Stunningly, while we were sitting there, a Wilson’s storm petrel straying a good way from the coast flew through and pooed on me. I kid you not. We all had a good laugh about that, and decided it was quite lucky and somewhat symbolic of the season.”

This is an edited extract from the essay Buried Treasure in Griffith Review 77, available now.

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