San Francisco Chronicle

Melting glaciers put fresh water supply at risk

- By Carlos Valdez Carlos Valdez is an Associated Press writer.

LA PAZ, Bolivia — The snow appears to be pristine on the Andean peaks that loom above Bolivia’s capital, but even here ash and smog reach up to a remote plateau that is home to the world’s highest atmospheri­c observator­y.

It’s an ideal site for a team of internatio­nal scientists who collect data on pollution that has contribute­d to the rapid disappeara­nce of Andean glaciers.

Research at the Chacaltaya station, which is located at 17,192 feet above sea level, has a pressing urgency: The retreat of glaciers, which is compounded by global warming, threatens the main source of fresh water for residents in the nearby cities of EL Alto and La Paz — and the crops on which they rely.

“If temperatur­es continue to rise, these high-altitude glaciers will also lose their mass of ice and there will only be snow on the summit,” said glaciologi­st Patrick Ginot. “This will happen all along the Andes.”

Last year, Ginot was part of a team of scientists that transporte­d chunks of ice from a melting Bolivian glacier to Antarctica to be preserved for posterity and future study as part of a global project called “Ice Memory.”

The Chacaltaya station is an important place to collect data samples partly due to its own location on the remnants of a glacier. The glacier, which is thought to be about 18,000 years old, once served as the site of Bolivia’s only ski resort before it melted a decade ago.

Initially, the station was launched as a cosmic ray observator­y in the mid-1940s, when just hauling up heavy scientific instrument­s on the back of llamas was a feat in itself. But Chacaltaya’s altitude and location near the Amazon region — and its proximity to Bolivia’s capital city — eventually led scientists to obtain informatio­n about the pollution released from the burning of forests, coal, oil and gas.

In 2012, the site became an atmospheri­c station used to measure greenhouse gases, reactive gases and particles that can spread all the way to the Pacific Ocean hundreds of miles away. Its altitude is only rivaled by a station recently built by China on the QuinhaiTib­et plateau near Mt. Everest which sits at 17,060 feet.

Chacaltaya, which means “Cold Road” in Aymara, is jointly funded and managed by groups from the United States and Europe, and the initiative is led by Universida­d Mayor de San Andres in La Paz.

Fernando Velarde, a physicist who works at the observator­y, said the data is shared with the internatio­nal community.

 ?? Juan Karita / Associated Press ?? The Chacaltaya station, the world’s highest atmospheri­c observator­y at 17,192 feet, collects data on pollution that has contribute­d to the rapid disappeara­nce of Andean glaciers.
Juan Karita / Associated Press The Chacaltaya station, the world’s highest atmospheri­c observator­y at 17,192 feet, collects data on pollution that has contribute­d to the rapid disappeara­nce of Andean glaciers.

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