Sophie Darfeuil is racing against time to preserve thousands of years of history from the world’s melting glaciers, saving the unknown past for a future she won’t live to see
Sophie Darfeuil thinks a lot about the future. In her lab at the Institut des Géosciences de l’Environnement in Grenoble, France, the research engineer examines tiny slivers of ice collected from the world’s glaciers. Hidden inside each fragment is a story that goes back thousands of years, a record the Ice Memory project hopes to preserve. But there’s a looming threat to her daily work: we’re running out of ice.
As snow falls on mountaintops, it carries with it trace chemicals, dust, pollen, and insects. Even small bubbles of air – samples of the atmosphere – are trapped between the snowflakes. Year after year, layer by layer, the snow deepens, compresses, and solidifies into clear blue ice. As it does, a historical record that can stretch back thousands of years is written.
There are many kinds of information in the ice, says Darfeuil. “We can learn about volcanic emissions, impacts, climate variations, glacial variations, the dynamics of the climate, natural process, and anthropogenic changes, all the processes driving the climate,” she explains. Even our brief flirtation with leaded petrol is there, recorded as a poisonous blip in the mid 20th century.
The deeper you look into the ice, the further back in time it takes you. From Antarctic cores, scientists have been able to reconstruct the climate stretching back 800,000 years. This is how we can be sure that in the last 100 years, the global temperature has increased so much faster than natural cycles of the past. While ice recovered from the polar regions speaks of global trends, that recovered from glaciers tells local stories. “If you want to find out about industrial pollution in Europe, you’ll find it in Mont Blanc,” says Darfeuil. “For volcanic activity in South America, you will find it in the Andes.”
But this great library is vanishing. Across the world, glaciers are in retreat. Rising temperatures and shifting weather patterns mean the colossal, frozen rivers are receding, losing more ice than they gain every year. And so our window into the past is vanishing too.
“It’s important to protect this ice. It’s going to disappear. We have to do it now” – Sophie Darfeuil
“Most glaciers are warming, and even before disappearing, the quality of the ice is diminishing,” says Darfeuil. For some glaciers, it’s already too late. The snowy peaks of Kilimanjaro have withdrawn by 90 per cent; the mountaintop will be snow-free within a few decades. Of the 150 glaciers that gave the US Glacier National Park in Montana its name, only 25 remain. “It’s important to protect this ice,” says Darfeuil. “It’s going to disappear. We have to do it now.”
The goal of the Ice Memory project is to collect samples from 20 endangered glaciers in 20 years. For each, a team of scientists will drill a hole as deep as 140 metres into the glacier, carefully removing the ice intact. Ideally, they will take three cores from each glacier. This is hugely ambitious. “The Bolivian drilling required 15 scientists for two months, plus 70 porters, plus mountain guides, plus a cold chain from Bolivia to Grenoble,” says Darfeuil. “It’s almost 11 months’ work for one core”.
Things don’t always go to plan. Only two cores were recovered from Mont Blanc and extreme weather conditions meant the team sent to the Illimani glacier in Bolivia did not recover the requisite three cores either. Two more expeditions to the Russian Caucaus last year recovered just two cores each. “You have to arbitrate your objectives and the health and safety of the team,” says Darfeuil. “It’s not such an easy goal at 6000m above sea level.”
Each core is a cylinder of ice 10cm in diameter. They are cut into metre-long sections, packed in stainless steel tubes, and labelled for transport. Months or even years later, half a world away in Grenoble, Darfeuil will remove a section of ice from a high-security industrial freezer and cut a 3cm slab from the core. Working in a lab chilled to -25°C, Darfeuil cuts this sample into several pieces destined for different experiments. Each piece, now not much bigger than the ice cube in your drink, is placed inside a melter, like a gem held in a steel and glass display case. The melter gradually warms the ice, drawing away the water and gases released for analysis. Each page from this record book can only be read once – then it is gone forever. “We have to destroy the ice to analyse it,” says Darfeuil. “There’s a lot of pressure in the analysis, if you miss it, it’s lost,” she says. “It’s so precious. It requires so much organisation, so many people.”
The data collected by Darfeuil and her colleagues is crucial for more policy makers who make decisions about the future of our environment. More than 50 per cent of the data used by the Intergovernmental Panel on Climate Change is extracted from ice cores. “The scientific information that is in the ice is very, very important to understand past climate and past environment,” says Darfeuil, “and to anticipate the upcoming changes. Keeping the information in good shape is absolutely crucial for humanity today and humanity tomorrow.”
“The scientific information that is in the ice is very, very important to understand past climate and past environment” – Sophie Darfeuil
In fact, as well as stretching back through time, the Ice Memory project reaches forward into the future. Glacierology is a science in its infancy, and it may outlast its subject matter. “Today we don’t have all the techniques or ideas to extract everything and understand everything from the ice,” says Darfeuil. “We are convinced scientists in one or two decades, or even four centuries, will have new ideas and new techniques. We have to do things right now to preserve what we can for future”.
This is why the scientists need to retrieve multiple samples from the glaciers: one core from each is destined for a cold storage chamber buried in the freezing wilderness in Antarctica – the only way scientists can be certain the ice will stay frozen for as long as is necessary, whether that’s decades or centuries. Careers will grow and ebb, governments will crumble and be replaced; the ice cores in Antarctica will outlast all of them.
This puts Darfeuil astride millennia – saving the unknown past for a future she won’t live to see. Centuries from now, a scientist will echo her daily work, perhaps even using equipment based on designs that Darfeuil is creating now. “We’re building a link between the scientists of today and those in three or four centuries. To be part of this link is a special bond, it’s nice,” she says. “Our generation and those to come will have to face big changes. We have to minimise our impact on the environment. We have to think about the future, especially when you’re a mother, and I am. I think about the future, and I’m confident that humanity can do great things.”