Tropical glaciers, which are especially at risk from climate warming, have melted rapidly in recent decades.
The question, scientists say, is how much?
Researchers funded by the U.S. National Science Foundation studied exposed bedrock at the edges of glaciers in the tropical Andes Mountains of South America.
The results show that the glaciers are smaller now than they have been in at least 11,700 years. The conclusions are published in the journal Science.
Scientists predicted that tropical glaciers would melt as temperatures warmed in equatorial regions.
Rock samples adjacent to four glaciers in the Andes Mountains show that the glacial retreat has happened far faster than expected, however.
The four glaciers are the Pan de Azucar Glacier in Colombia, Zongo Glacier in Bolivia, Queshque Glacier in Peru and Charquini Norte Glacier in Bolivia.
“These sobering results will help us improve projections of the implications for communities and ecosystems that depend on meltwater from these vulnerable tropical glaciers,” says Jonathan Wynn, a program director in NSF’s Division of Earth Sciences.
