A calendar shows the rapid disappearance of glaciers as a function of warming

The study, led by researchers from the Federal Institute of Technology in Zurich (ETH), the Swiss Federal Institute for Forestry, Snow and Landscape Research and the Vrije University of Brussels, appears this Monday in the journal Nature Climate Change and calls for ambitious measures to be taken to curb climate change.

Scientists have calculated for the first time how many glaciers disappear each year around the world, and what would be the schedule in which they would be lost based on different warming scenarios. “For the first time, we have calculated when each of the Earth’s glaciers will disappear,” says lead author Lander Van Tricht, a glaciologist at ETH Zurich.

Their findings reveal that regions with many small glaciers at lower altitudes or near the equator are the most vulnerable to losing ice masses, including the Alps, the Caucasus, the Rocky Mountains, and parts of the Andes and African mountain ranges found at low latitudes.

“In these regions, more than half of all glaciers are expected to disappear within the next 10 to 20 years.s”, destaca Van Tricht.

How many will survive?

Scientists have modeled the rate of glacial retreat for scenarios in which global warming increases 1.5 degrees, 2 degrees or 4 degrees above pre-industrial levels by the end of the century.

Nivel Global, With an increase of more than 4 degrees in global temperature in 2100, there would only be about 18,000 glaciers left on the planetcompared to the 100,000 that would be maintained if 1.5 degrees are not exceeded.

In the case of the Alps, with an increase of 1.5 degrees only 12% of the glaciers would survive by the end of the century (approximately 430 of the 3,000 that still remain in 2025); with more than 2 degrees only 8% would remain (about 270 glaciers), and with 4 degrees more there would barely be a trace of 20 glaciers left (about 1%).

In the Rocky Mountains, in America, around 4,400 glaciers would resist in a 1.5 degree rise scenario (25% of the current 18,000 glaciers); while with 4 degrees there would only be 101 left (which represents a loss of 99%).

In the Andes and Central Asia, around 43% of glaciers would survive a 1.5 increase scenario; but at 4 degrees only about 950 glaciers in the Andes would survive (94% would be lost) and only about 2,500 in Central Asia (a decrease of 96%).

Extinction peaks

The researchers also calculate what they call the “peak glacier extinction,” which would occur when the number of glaciers that disappear in a single year reaches its maximum. After that peak, annual loss rates slow because most of the smaller glaciers have already disappeared.

With an increase of 1.5 degrees, the peak of extinction would be reached around 2041when approximately 2,000 glaciers would disappear in just one year. While with an increase of 4 degrees, the peak would move to 2055, but it would mean the loss of about 4,000 glaciers in one year.

“That the peak occurs later with more intense warming may seem paradoxical. The reason is that in warmer conditions, not only small glaciers completely melt, but also larger ones disappear,” says another of the authors, Daniel Farinotti, professor of Glaciology at the ETH in Zurich.

Implications

The authors emphasize that, compared to previous studies that focused on measuring glacier loss by mass and volume (which allowed projections on sea level rise and water resource management), this new approach has other political, economic and cultural implications.

“The melting of a small glacier barely contributes to the rise in sea level. But when a glacier disappears completely, it can seriously affect tourism in an area,” Van Tricht points out in that sense.

“It also means that every tenth of a degree counts to stop the decline. Ambitious climate measures must be adopted urgently,” Farinotti emphasizes.