London — Switzerland's alpine glaciers have lost 10% of their volume over the last two years alone, the Swiss Academy of Sciences reported Thursday, calling the sudden reduction clear evidence of the "very critical state" of the climate. The glaciers have shed as much ice in two years as they did in the 30 years between 1960 and 1990.

The rate of ice loss in 2023 was 4%, the second worst year on record after 2022, when they lost 6% of their volume.

"It's the second most negative year," Matthias Huss, the head of GLAMOS, an organization that monitors glaciers in Switzerland and collected the data for the academy's report, told CBS News. "We've seen the two worst years in a row, and this is even more worrying."

The extreme weather conditions of the past two years have led to the disappearance of many smaller Swiss glaciers completely, as well as the collapse of some glacier tongues — the part of the glacier that extends into a body of water.

"I hope that this is one more piece of evidence that really shows that the climate system is really in a very critical state," Huss said.

The reason for the record ice loss is high summer temperatures and low snow volumes during the winter, the academy said.

The World Meteorological Organization (WMO), the United Nations' weather agency, said summer of 2023 included the "hottest three months on record" globally, warning that "climate breakdown has begun."

"We are in uncharted territory and we can expect more records to fall as El Nino develops further and these impacts will extend into 2024," Christopher Hewitt, WMO Director of Climate Services, said in July. "This is worrying news for the planet."

Glacier experts have warned that some of the world's bigger glaciers could disappear within a generation without a dramatic reduction in greenhouse gas emissions.

Traditionally, glacial ice builds up during the winter and provides vital water for crops, transit and millions of people on multiple continents during the summer as it slowly melts, feeding rivers.

"They make it very visible," Huss told CBS News. "People can really understand what is happening, with huge glaciers disappearing and shrinking. This is much more impressive than seeing another graph with rising temperatures."

Haley Ott

Haley Ott is an international reporter for CBS News based in London.

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