Half of the planet's glaciers will melt by 2100, even if humans try to lower Earth's temperature under the Paris Agreement. Recent research has found the scale and impact of glacier loss to be greater than previously thought.
The researchers found that 49% of the glaciers would disappear. This will happen in the most optimistic scenario where the Paris Agreement manages to keep the temperature 1.5 degrees Celsius above pre-industrial times.
However, if global warming continues under the current 2.7 degree Celsius warming scenario, the losses will be more significant. As much as 68% of the glacier will disappear. There will be almost no glaciers left in central Europe, western Canada and the US by the end of the next century if this happens.
Sea level rise
Melting ice and loss of glaciers will significantly contribute to sea level rise. It also threatens water supplies and increases the risk of natural disasters such as floods. The study looked at all of the glacial ice shelves except the Greenland and Antarctic ice sheets.
If temperature rise were limited to 1.5 degrees Celsius, average sea level would rise by 90 mm from 2015 to 2100. But with 2.7 degrees Celsius warming, glacial melting would cause sea level rise of about 115 mm.
The melting of iceberg glaciers is believed to contribute to more than a third of sea level rise. Many of these losses are unavoidable, but the magnitude of the losses is directly related to the increase in temperature. So tackling the climate crisis is key.
"The rapidly increasing mass loss of glaciers as global temperatures rise beyond 1.5 degrees Celsius underscores the urgency to make more ambitious climate maintenance promises to preserve glaciers in this mountainous region," the researchers wrote as quoted by The Guardian.
The team used two decades of satellite data to map the planet's glaciers with greater precision than ever before. Previous models relied on measurements of specific glaciers, and that information was then extrapolated.
But now researchers can get data points on each of the planet's 200,000 glaciers. For the first time, this provides insight into how much glaciers will be lost under different climate change scenarios.
The study's lead author, Dr David Rounce of Carnegie Mellon University and the University of Alaska Fairbanks, said this was the first time they had isolated the amount of glaciers that would be lost.
"Most of the glaciers that will be lost are small, currently less than 1 sq km. Although they contribute less to the total volume, they are the most vulnerable to change. This is why the total mass loss is less. So, for example, under scenario 2, 7 degrees Celsius, 68% of the glacier will disappear but the relative mass will be less, projected to be 32%," he explained.
Tiny glaciers are an important source of water and livelihoods for millions of people. Rounce says, when we think about the locations where most people see and visit glaciers, it's really in accessible locations, like in central Europe, or in the high mountains of Asia.
"There are lots of smaller glaciers in this area. They really are the core of the people and the economy in those locations," he said.
Lower mountains such as the Alps and Pyrenees were among the worst affected. In the Alps, for example, by 2050, glaciers are expected to be 70% smaller on average, many smaller glaciers will have disappeared, with snow peaks replaced by bare rocks in some locations, and with significant loss of biodiversity.
"Alpine flowers could go extinct after the glaciers disappear as more competitive species colonize higher areas on the mountain. The proglacial environment is very sensitive to global warming, and mountain species are subject to the "escalator to extinction," said Rounce.
This isn't the first study to project sea level rise from glacial melt, but the projections are more accurate than previous models. The current study follows research from 2021 which found that the rate of melting of glaciers has doubled in the past two decades, contributing more to sea level rise than the Greenland or Antarctic ice sheets.