A new study is using millions of satellite images to generate a clearer picture than ever before of the fate of the world’s glaciers.
Study co-author Brian Menounos of the University of Northern British Columbia says those glaciers are getting smaller, faster — with those in western North America thinning more quickly than almost any others in the world.
The amount of ice that the study says is melting away each year is almost unimaginable.
Menounos says it’s 267 billion tonnes a year.
Just one billion tonnes is equal to the mass of 10,000 fully loaded aircraft carriers.
The pace is picking up, especially in North America, where glaciers are melting four times faster now than they were 20 years ago. Half the world’s glacial loss is coming from the United States and Canada.
WATCH | Aerial views of the Klinaklini Glacier in 2019:
With glaciers being a crucial source of fresh water, Menounos says the findings have important lessons for water managers.
The annual melt rate from 2015 to 2019 is 71 billion more tonnes a year than it was from 2000 to 2004. Global thinning rates, different than volume of water lost, doubled in the last 20 years and “that’s enormous,” said Romain Hugonnet, a glaciologist at ETH Zurich and the University of Toulouse in France who led the study.
Half the world’s glacial loss is coming from the United States and Canada.
Alaska’s melt rates are “among the highest on the planet,” with the Columbia glacier retreating about 35 metres a year, Hugonnet said.
Almost all the world’s glaciers are melting, even ones in Tibet that used to be stable, the study found. Except for a few in Iceland and Scandinavia that are fed by increased precipitation, the melt rates are accelerating around the world.
The near-uniform melting “mirrors the global increase in temperature” and is from the burning of coal, oil and gas, Hugonnet said. Some smaller glaciers are disappearing entirely. Two years ago, scientists, activists and government officials in Iceland held a funeral for a small glacier.
‘Memorial of the climate crisis’
“Ten years ago, we were saying that the glaciers are the indicator of climate change, but now actually they’ve become a memorial of the climate crisis,” said World Glacier Monitoring Service director Michael Zemp, who wasn’t part of the study.
The study is the first to use this 3D satellite imagery to examine all of Earth’s glaciers not connected to ice sheets in Greenland and Antarctic. Past studies either only used a fraction of the glaciers or estimated the loss of Earth’s glaciers using gravity measurements from orbit. Those gravity readings have large margins of error and aren’t as useful, Zemp said.
Ohio State University’s Lonnie Thompson said the new study painted an “alarming picture.”
WATCH | Melting ice and glaciers could lead to water crisis:
Shrinking glaciers are a problem for millions of people who rely on seasonal glacial melt for daily water and rapid melting can cause deadly outbursts from glacial lakes in places like India, Hugonnet said.
But the largest threat is sea level rise. The world’s oceans are already rising because warm water expands and because of melting ice sheets in Greenland and Antarctica, but glaciers are responsible for 21 per cent of sea level rise, more than the ice sheets, the study said. The ice sheets are larger longer term threats for sea level rise.
“It’s becoming increasingly clear that sea level rise is going to be a bigger and bigger problem as we move through the 21st century,” said National Snow and Ice Data Center director Mark Serreze.