In the first two decades of this century a funny thing happened in high Asia. The glaciers of the great Karakoram mountain range started growing. Some of them crept across the Karakoram Highway where it snakes up to Pakistan’s border with China. All of them baffled scientists, who called this growth in an age of climate change the Karakoram Anomaly.
It’s over now. The glaciers have pretty much stopped growing. There were multiple theories for the anomaly, including a chilly summer microclimate, more evaporation and precipitation caused by irrigation, and (most likely) more evaporation and precipitation thanks to climate change. In any case, most of the glaciers are now in retreat. “They’re catching up with what’s happening in the rest of the world,” says Dr Heidi Sevestre, the most interesting person I’ve met among the 30,000 milling around Cop.
Sevestre grew up in the shadow of Mt Blanc. She had friends who’d head out of town after school and ice-climb up the snout of the Glacier des Bossons direct from a car park in the bottom of the Chamonix valley. A little later, as a glaciologist, she’d give talks at the great natural portal where the Mer de Glace used to appear on its long run down from behind the Aiguille du Midi. “People are lost for words when they go there now,” she says, because of course the glacier isn’t there.
The Mer de Glace is France’s symbol of climate change. It’s lost 200 metres of depth and at least two kilometres of length in the past century. What’s left of it drains into the Rhône, which by August every year depends on alpine glaciers for 40 per cent of its flow. When they’re gone, that 40 per cent will be gone too, and not the least of France’s worries is where it will find the water to cool the ten nuclear reactors positioned along the river between Bugey and Tricastin.
France will find a way, but the threat posed to people by glacial retreat in poorer parts of the world is dire and well-known. Two billion depend on meltwater from the Himalayas; tens of millions on the Andean glaciers of Bolivia and Peru. The ice keeps melting, and giving, when seasonal snows have disappeared, but an astonishing amount of it has gone for good.
The world lost 28 trillion tonnes of ice between 1994 and 2017, according to a new study by the Centre for Polar Observation and Modelling in Leeds. What’s gut-wrenching for people who love the way glaciers carve the earth and cool the air is that 6.1 trillion of those 28 trillion tonnes are accounted for by mountain glacier loss specifically. That’s nearly as much as lost from Antarctic ice shelves and 60 per cent more than lost from the Greenland ice sheet. So this is not like those audits of the earth’s fresh water, which show that all rivers combined are a trickle compared with Lake Baikal. For their volume, the glaciers that loomed over Hannibal and Turner are doing a disproportionate amount of melting. Those formed by the snows of Kilimanjaro and the Rwenzori in equatorial Africa are doomed whatever happens.
These are tragedies in and of themselves. Regardless of the people they affect, they’re failures of human stewardship; abject and shaming. The melting started about a century before most other climate change canaries started singing (sea surface temperatures, extreme weather events, crop yields) but Sylvestre says the root cause is the same; rising anthropogenic greenhouse gas levels. Glaciers are just sensitive canaries.
All of which should make the Cryosphere pavilion at Cop depressing, but it isn’t. Unlike so many others, it’s greenwash-free, non-corporate and it tells a story. (We included a short item on it in yesterday’s Net Zero Sensemaker in which we called it sad, but that failed to take account of how the story might end.)
For our purposes it starts around the time of the crusades. The Medieval Warming Period – a geological nanosecond ago – was the last time glaciers were this short. We know this because hikers and researchers keep finding ancient leather sandals high up on alpine passes that are snowbound most of the year even now.
Chapter two was the Little Ice Age, brought on by more volcanic activity or less solar; perhaps both. It was over by 1850, after which a gradual and then rapid warming process began that’s accelerating to this day.
The significance of the story to this point is that glaciers react quickly and predictably to climate change. They can spring surprises – in 1892 a huge pocket of water broke out of its ice cave in the Tête de Rousses glacier on Mt Blanc’s west flank and killed 175 people in St Gervais les Bains below. But even these surprises are the result of inexorable melting.
The downside of this predictability is that we know with great confidence what will happen to the world’s glaciers if we go on pumping CO2 into the atmosphere. At current rates of growth of greenhouse gas emissions there’ll be almost no glaciers left anywhere by 2100. Even if all countries follow through on climate pledges published before Cop 26, only remnants of glaciers in the Arctic, the Himalayas and Patagonia will survive that long. If all the updated promises presented at Glasgow are kept, some “mid-latitude” glaciation (including in the Alps) will survive a couple of centuries longer.
But if we do better, something remarkable could happen. If steep emissions cuts over the next decade put the planet on course for peak warming of 1.6 to 1.8 degrees, declining thereafter, the rate of retreat of some glaciers will slow by the middle of this century. And then, by 2100, “some glacier regions in the mid-latitudes… may begin to show very slow re-growth”.
That is one finding of the 2021 State of the Cryosphere report. It incorporates two enormous “ifs” and is buried on page 17 along with much bleaker forecasts for higher emissions scenarios and lower latitudes (glaciers closer to the equator). But an accompanying graph shows unmistakably that alpine glaciers will start regrowing around 2090 in a world aligned to 1.5 degrees of warming or even a little more.
Fancy that. The retreat in reverse. Ice climbers heading back to the des Bossons car park. The Karakoram Anomaly revived and no longer anomalous. The world’s great natural irrigation system, back in action, in my grandchildren’s lifetime, thanks to global cooling. All we have to do is conquer global warming first – and a point too often lost in the noise of Cop is that we have to anyway.
“These glaciers are our friends,” Sylvestre says. And our conscience.
Photograph Roberto Moiola/Sysaworld/Getty Images
With thanks to our coalition members: a network of organisations similarly committed to achieving Net Zero