Four Women, One Terrible Arctic Winter
CLIMATE SENTINELS 2021
INTRODUCTION
What This Expedition Was About
In March 2021, four scientists set out to do something that had never been done: cross Spitsbergen on skis, hauling their own equipment and scientific instruments, without a single drop of diesel. No snowmobiles, no helicopters, no generators — just pulkas, Nordic skis, and the conviction that the way we do science has to be as honest as the science itself. Climate Sentinels was an expedition, a protest, and an experiment all at once.
Discover the expedition
CLIMATE SENTINELS 2021
THREE YEARS IN THE MAKING
It begins, absurdly enough, on a snow-dusted plateau above Annecy, with a woman hauling car tyres.
That woman is me. Winter 2021. Between lockdowns, the ski lifts are idle and the trails nearly empty. On the days I swap the tyres for a pulka — that lightweight sled inherited from the Inuit — I load it with a dozen de-icing canisters from my garage until it tips the scales at fifty kilograms. Then I clip on the harness and start climbing. Three hours up, three hours back, day after day, in the kind of cold that wakes up old injuries: the back, the shoulder I dislocated once inside a glacial cave. The body keeps its accounts.
The few hikers I pass cannot resist stopping.
“Did you lose a bet?”
I burst out laughing. “No — I’m training. I’ve got a rather intense programme for a polar expedition.”
Three years in the making, to be precise. Three years of dreams, planning, setbacks, and a global pandemic that pushed the whole thing back by twelve months. But now, now we are almost there.
THE SCIENCE
We had two scientific missions, and both were urgent.
The first was to validate data from NASA’s ICESat-2 satellite, launched in September 2018 to track changes in the altitude of ice and snow surfaces across the poles. A satellite is only as good as its calibration, and calibrating it requires people on the ground — or rather, on the ice — taking precise measurements of snow depth, density, and temperature. Every five kilometres, we would stop, drill into the snowpack, and feed data back to the satellite team. Unglamorous, essential work.
The second mission involved something darker: black carbon.
You know black carbon, even if you don’t know its name. It is the grime on a city railing after you run your finger along it. The soot in a chimney flue. The barely visible particulates that pour from exhaust pipes and accumulate wherever combustion happens — burning petrol, coal, diesel, even wood. In a city, it is everywhere, unremarkable, part of the visual texture of urban life.
In the Arctic, it should not exist.
And yet it does. Particles emitted hundreds or thousands of kilometres away are lifted into the atmosphere, carried by wind, trapped in clouds, and eventually deposited on the Arctic snowpack with precipitation. The evidence is no longer only detectable by instruments — it is visible to the naked eye. Glaciers in western Greenland that once gleamed white in summer now show vast grey and black streaks across their surface, so dark that solar radiation is absorbed rather than reflected, accelerating melt. Another vicious cycle in a system full of them.
By collecting a hundred snow samples at regular intervals across Spitsbergen, we hoped to map the distribution and concentration of black carbon across the archipelago — a dataset that would sharpen our understanding of how far industrial pollution truly reaches.
QUARANTINE. AND FOUR INSTEAD OF SIX.
March 2021. Ten days of quarantine in Oslo. Closed borders. Equipment that did not arrive on time. The difficulties stacked up fast.
In the end, only four of us would go into the field: Silje, Nina, Anne, and me. Doroée and Alia, anchored by circumstances at home, became our remote logistics and guidance team — indispensable in their own way, navigating decisions with us from thousands of kilometres away. Losing two team members before the start was a blow, but it sharpened the focus of those of us who were going.
Expeditions to Svalbard typically take place in April: cold enough to stabilise the ice and the sea ice, bright enough (the polar day is long) to spot a polar bear from a safe distance. We were pushing the timing slightly, which added its own layer of uncertainty.
The night before departure, none of us could sleep. We checked and double-checked every item of kit, weighed every decision. I looked at the thermometer.
Plus five degrees Celsius.
Positive five.
“That’s… odd,” someone said.
“It’ll drop in a couple of days,” said someone else.
We shouldered our packs and stepped out into the grey morning.
The Team
Climate Sentinels was born from a shared frustration.
Most of us who study glaciers and Arctic systems have spent years as the only woman in the room — or on the ice. The “ice guys” world is a real one, and while it is changing, it changes slowly. We wanted to move faster.
Six of us came together: Anne, Silje, Nina, Doroée, Alia, and me, Heïdi from the Alps. Each of us a scientist, each of us experienced in polar environments, each of us fed up with a very specific contradiction at the heart of our work.
To study the damage caused by fossil fuels, we burn fossil fuels. Heavily. We fly to remote airports, board fuel-heavy ships, charter helicopters for the last leg, then run diesel generators on-site to power our instruments. The carbon footprint of a single polar expedition can be staggering — and here we are, measuring the melting consequences of that very footprint. The absurdity had become unbearable.
We wanted to prove that a different kind of science was possible.
Our answer: go back to basics. Each of us, on cross-country skis, would haul a pulka loaded with 80 to 100 kilograms of camping gear, scientific equipment, and food. As we ate through our provisions, the weight would be replaced by snow and ice samples — so the load would stay constant throughout the journey. No fossil fuels for transport on the ground. No helicopters. No snowmobiles. Just legs, skis, and the old techniques the Arctic explorers knew before engines existed.
Walk the talk, and talk the walk.
The route: one month across Spitsbergen, the largest island of the Svalbard archipelago, from one research station to the next. Ny-Ålesund to Pyramiden, Pyramiden to Sveagruva, Sveagruva to Hornsund — roughly 450 kilometres. As far as we knew, it had never been done on skis. Good. If it had been easy, someone would have done it already.
THE WORST WEATHER IN LIVING MEMORY
What followed was unlike anything any of us had experienced in years of polar fieldwork.
Within two hours of setting off, before we had even found our ski legs, the blizzard came. Not a gradual build — a sudden, savage arrival, like a predator lunging. Within minutes, the wind was roaring, the sky had collapsed to white, and visibility was near zero. We had no choice but to pitch the tents and wait.
Over the two weeks that followed, the weather simply did not relent. The wind was ferocious — strong enough to knock over the pulkas, all 70 to 80 kilos of them, and us with them. Temperatures refused to drop below zero degrees, which meant the snowpack was unstable, saturated, treacherous. We sweated and froze simultaneously: our clothing, designed for deep cold, became sodden and impossible to dry. Our boots were pressure cookers for our blistered feet. We watched enormous avalanches peel off the mountain flanks in the distance. Snow fell continuously, relentlessly, one storm chasing the next off the sea.
Our progress was agonisingly slow.
This patterns kept coming back. To the point when it became impossible to sleep in tents, we had to dig tunnels in the snow to survive winds above 140 km per hour. On day seven, we were still far from the food cache we should have reached that day. On day twelve, the two dogs we had brought along as polar bear sentinels — brave, reliable animals in ordinary conditions — were so terrified by the wind that they refused to move. Our food was running dangerously low. On day fourteen, in a narrow window between two storms, we finally reached the cache, ravenous, depleted, but still moving.
Svalbard had not seen conditions like this in decades. Climate change is not only about warming — it is about disruption. Weather patterns that were once predictable have become erratic. Precipitation is more frequent, storms more violent, the frozen landscape less stable and less legible than it once was. Svalbard is becoming wilder.
AFTER THE STORMS
Then, finally, the thermometer fell.
Minus fifteen. Minus twenty. The wind dropped. The sun reappeared, hard and brilliant, flooding the plateau with the particular clarity of Arctic light that makes everything — shadows, crystals, distance — startlingly precise. Our route curved south.
We could have turned back to Longyearbyen, capital of Svalbard. Hot showers, soft beds, restaurant food — the temptations were not abstract. We did not turn back.
Instead, we resumed the scientific protocol that the storms had interrupted: snow samples every five kilometres, measurements of depth, temperature, and density at each stop. In the cold, every halt bit at us, so our gestures became quick and coordinated, economical. Three weeks of shared hardship had stripped away whatever formality or self-consciousness remained between us. We knew each other’s rhythms, each other’s limits, each other’s silences. Trust built in extreme conditions is a different kind of trust from the kind built in meeting rooms.
The samples accumulated. The data built up, kilometre by kilometre. One hundred snow cores, each one a small frozen archive of what the wind had carried here from far away.
BAMSEBU
After nearly three weeks on the ice, we came across a small wooden cabin at the edge of nowhere — Bamsebu. Built from timber washed up by the sea, it had no running water, no mains electricity, no connection to the world except what two solar panels, a small wind turbine, and a radio could provide.
Two women lived there. Hilde and Sunniva were completing their second consecutive winter at Bamsebu, collecting scientific data for international research institutes through their project, Hearts in the Ice. We spent two days with them, and those two days stayed with me long after the expedition ended.
I asked them what the secret was — nine months of the year, in complete isolation, in one of the harshest environments on Earth.
They answered in unison: “Waste less.”
At Bamsebu, water is not something you turn on. It is snow or ice you go outside to fetch — in any temperature, any wind, any darkness — hack into pieces, carry inside, melt, filter, boil, and only then drink. You do not leave the tap running while you brush your teeth. You cannot. Every small act carries the full weight of the effort required to make it possible.
Electricity is rationed by weather. When the panels and the turbine produce enough, the computers come on — primarily to connect with schoolchildren around the world, share their data, explain what is happening to the Arctic. When there is not enough, they sit in the dark and do not waste what isn’t there.
What they had built, entirely by necessity, was a kind of radical clarity. Nothing was taken for granted because nothing was easy to obtain. And in that stripping-away, Hilde told me, she had never felt so free.
I thought about that for many kilometres afterwards, pushing into the wind.
THE FINAL PUSH
Our original plan had been to reach Hornsund, the southernmost point of our route. The sea ice and our accumulated delays made that impossible in the end to be picked up by boat. We redirected toward Calypsobyen, and on the last day, we skied thirty-four kilometres — the longest single day of the expedition — to reach it.
We left in the morning. By the time we arrived, the sky had turned extraordinary: crystal and rose and mauve and orange, the midnight sun sitting just above the horizon, painting everything in colours that have no equivalent elsewhere. I was exhausted in a way I have no words for. I was also filled with something that felt very close to joy — not the noisy kind, but the quiet, solid kind that settles in when you have pushed yourself far enough to find something true on the other side.
We made it. Four women, one month, hundreds of kilometres, a hundred samples, the worst weather Svalbard had seen in a generation, and we made it.
