Falling Off a Cliff: Glaciers Lost 12% of Ice Volume in Just Four Years

Glaciers across western North America and Switzerland have experienced their most severe mass loss on record, shedding roughly 12-13% of their total ice volume between 2021 and 2024—a rate that doubles the previous decade’s losses.

The dramatic acceleration stems from a perfect storm of climate factors: extended heat waves, reduced snowfall, and surface darkening that transforms reflective white ice into heat-absorbing black surfaces.

The findings, published today in Geophysical Research Letters, reveal that western Canada, the continental United States, and Switzerland lost ice at rates of 22.2 and 1.5 gigatons per year respectively during this four-year period. To put this in perspective, these regions lost as much ice in four years as they typically would in eight.

When White Ice Turns Dark

Perhaps the most striking discovery involves what researchers call the “ice-albedo feedback”—a process where darkening glacier surfaces absorb more solar radiation and accelerate their own destruction. In North America, this darkening comes primarily from wildfire ash and black carbon particles that settle on ice surfaces like a heat-trapping blanket.

“2023 was the year of record, no question,” explained lead author Brian Menounos, a professor at the University of Northern British Columbia and chief scientist at the Hakai Institute. That year coincided with Canada’s worst wildfire season in recorded history, when more than one million hectares burned.

In Switzerland, Saharan dust storms serve a similar function, with notable dust deposition events in 2022 and 2024 contributing to record mass loss. The research team found that surface darkening alone accounted for nearly 40% of melting at Haig Glacier in Canada’s Rocky Mountains between 2022 and 2023.

Multiple Climate Hammers

The unprecedented ice loss resulted from several converging factors:

• Temperature spikes: Ablation season temperatures exceeded 2010-2020 averages by 1.5-2°C across the most ice-covered regions
• Early heat waves: Record-breaking spring and summer temperatures occurred near the summer solstice, maximizing available solar energy for melting
• Reduced snowfall: Below-average winter accumulation left glaciers more vulnerable to summer melt
• Firn zone loss: High-elevation areas that typically retain snow year-round have disappeared, exposing darker ice beneath

At monitored glaciers, the 2023 mass balance averaged -2.7 meters of water equivalent in North America, while all 23 Swiss glaciers reporting to the World Glacier Monitoring Service recorded losses exceeding -2.3 meters.

Models Missing the Mark

Current climate models used for glacier projections typically don’t account for surface darkening, firn evolution, or the cascading effects of extreme weather events like wildfires and heat domes. This oversight could mean existing timelines for glacier disappearance are overly optimistic.

Using sensitivity experiments at Haig Glacier, researchers found that warm summer temperatures contributed 46% of the unprecedented 2022-2023 mass loss, while firn zone loss added 22% and anomalously low ice albedo contributed another 17%. Low winter snow depth accounted for the remaining 15%.

“If we’re thinking, ‘Well, we have 50 years before the glaciers are gone,’ it could actually be 30,” Menounos noted. “So we really need better models going forward.”

Peak Water Already Passed

The research suggests both regions have likely reached “peak water”—the point of maximum runoff from glacier mass loss. As glacier area continues shrinking, total water release will decline even if thinning rates remain high. This transition carries significant implications for water security in mountain communities that depend on glacial meltwater during dry summers and drought years.

While the direct contribution to global sea level rise from these particular regions remains relatively small, the broader implications extend beyond rising oceans. Accelerated glacier loss increases risks of geohazards like outburst floods from newly formed glacier lakes, while longer-term declines in glacial runoff could impact both human communities and aquatic ecosystems.

The study encompassed extensive aerial surveys combined with ground-based observations from 27 glaciers across the three regions—representing about 55% of central European glacier volume and 91% of western North American ice cover outside Alaska.

As Menounos concluded, “Society needs to be asking what are the implications of ice loss going forward. We need to start preparing for a time when glaciers are gone from western Canada and the United States.”