Aug. 5 (Bloomberg) -- When the Chacaltaya glacier vanished six years sooner than scientists predicted, a victim of global warming, so too did the world’s highest ski run.

The loss of the 18,000-year-old glacier this year that loomed above Bolivia’s altiplano threatens to diminish water supplies to 2 million people clustered around La Paz, according to the World Bank, leaving Jade Dragon in China and India’s Gulmarg as the highest remaining ski areas for the adventurous.

“Chacaltaya was my bride in white, now she’s dressed for a funeral,” Alfredo Martinez, 74, said of the 17,785-foot-high (5,280 meters) glacier where he and Club Andino Boliviano members skied its sole run north of La Paz, Bolivia’s capital.

Chacaltaya, bridge of ice in the Aymara Indian language, has been a barren slope devoid of permanent snow for about six months. That’s when the glacier succumbed to warming weather during the Southern Hemisphere’s summer, its final two glacial tongues melting away even faster than the year 2015 that scientists had forecast for its disappearance.

Like shrinking ice sheets in Antarctica, climate change blamed on greenhouse-gas emissions including coal-fired pollution since industrial times has raised sea levels, led to the extinction of less-adaptable species and cost the world another glacier. From the Andes to the Alps, glaciers have retreated for 18 years, and twice as fast as a decade ago, says the University of Zurich’s World Glacier Monitoring Service.

Worrisome to city planners is that as Bolivia’s glaciers recede, the landlocked Andean nation’s water supplies grow more at risk -- a trend that may spread throughout South America and elsewhere as glacial melting is accelerating at a quicker pace than a United Nations forecast of just two years ago.

Largest Rivers Drying Up

Global warming, dams and the diversion of water for agriculture and industry are already drying up stream flows in 45 of the largest rivers, including India’s Ganges, the Yellow River in China, and the Congo and Colorado rivers. That affects tens of millions of people from China to India and the U.S.

South American residents, including those in La Paz and its sister city El Alto, may be similarly affected. La Paz’s main water supplies come from rainwater and melt-off from tropical glaciers in the Cordillera Real range, which includes Chacaltaya and the Tuni-Condoriri glacial system set in the mountains above the region’s largest reservoir.

Glacial runoff feeds into 10 hydroelectric plants that provide about 80 percent of the region’s power, said Edson Ramirez, head hydrologist at San Andres University in La Paz.

‘Going to Disappear’

“Sooner or later, all the tropical glaciers without exception are going to disappear,” Juan Carlos Alurralde, an engineer studying water solutions for Agua Sustentable, said in an interview at his office in La Paz.

In 2008, an estimated 20,000 hikers made it to Chacaltaya’s summit, according to the president of Club Andino, considered an easy ascent compared to the icy peak of Illimani, revered by the Aymara, that hovers in the distance.

On a cold July morning, about 20 tourists climbed from the Club Andino ski lodge to Chacaltaya’s summit for a broader view of the Cordillera Real mountains. Just below the summit, a tennis court-sized slab of ice was all that remained where there once was a glacial field navigable for 10-minute runs by skiers.

“It’s regrettable for the children, the youth of the city,” said Juan de Dios Guevara, Club Andino’s president. “Tourists will prefer the ski centers in Chile and Argentina.”

While Chacaltaya was Bolivia’s sole ski area, first developed in 1939, Club Andino sold its last ski ticket for its only tow line in 2003 after a tower anchored in the glacier fell to the ground as melting worsened. The glacier lost 80 percent of its volume over the last 20 years, scientists said.

Coca Tea, Anybody?

A lodge just below the peak that serves coca tea, a mild stimulant using the leaf that’s the raw ingredient for cocaine, remains open for hikers. Views from Chacaltaya’s summit on a clear day include snowcapped peaks and Lake Titicaca, the world’s highest commercially navigable lake.

Bolivians wanting to ski now have to travel to Argentina, whose ski areas in the Andes mountains include the world-renown Bariloche. Chile ski resorts include Portillo, site of World Cup races outside the capital Santiago.

Healthy glaciers add surface mass from precipitation and lose mass underneath from melting, maintaining roughly the same size from year to year. Chacaltaya and other glaciers began disappearing when rising temperatures disrupted that equilibrium so that the entire structure began to melt, Ramirez said.

Average temperatures around the capital rose about 1.4 degrees Fahrenheit in the past three decades, Felix Trujillo, head meteorologist with the country’s National Meteorology and Hydrology Service, said Aug. 3 at his office in La Paz.

Dry Seasons, Then Downpours

Climate change has also led to extended dry seasons and condensed periods of heavy rain in the region. Every month this year, precipitation in La Paz has been below historic averages, recorded from 1961 to 1990, except for February, when downpours set off mudslides that left 60 families homeless, Trujillo said.

Shrinking glaciers endanger about a third of the potable water supply to La Paz and El Alto, Water Ministry spokesman Arsenio Alvarez Beltran said.

“This year for the first time we haven’t reached the levels needed to guarantee supplies for the full year,” Ivan Rebollo, an engineer with the state water company Empresa Publica Social del Agua y Saneamiento, said in a July 30 interview regarding one of four supply systems to La Paz.

Tuni, Condoriri and dozens of other Andean glaciers will melt away over the next 40 years at present rates, cutting back on water supplies to Bolivia as well as Peru, Ecuador and Colombia, said the engineer Alurralde.

Mass Migrations?

In addition to the costs to cities, poor rural populations may migrate en masse as water supplies drop, pressuring governments, he said. Bolivia’s gross domestic product per capita is the lowest in South America, according to International Monetary Fund data.

Glaciers act as water coffers, helping power hydroelectric plants when rain is scarce. Peru alone will spend as much as $1.5 billion a year to combat the effects of glacier retreat on its hydropower, said Walter Vergara, head of Latin America climate-change projects for the World Bank.

Even as governments prepare to meet at a UN-sponsored climate summit this December in Copenhagen, Perito Moreno glacier in neighboring Argentina and maritime glaciers in Alaska and Norway are defying trends worldwide and increasing in size. Vergara said that shouldn’t delay infrastructure overhauls.

“Adaptation investments should take place today” as global warming isn’t going away, Vergara said. “Though the adaptation cost is going to be significant, it is likely to be less than the net impacts of climate change if no adaptation takes place.”

The World Bank is financing $33 million in projects in Peru, Bolivia and Ecuador to help those countries find and implement solutions related to water issues, Vergara said.

“If we do nothing, the future might be worse than we can imagine,” said the hydrologist Ramirez.

To contact the reporter on this story: Jonathan J. Levin in La Paz at JLevin20@bloomberg.netJose Orozco in Caracas at jorozco8@bloomberg.net

Last Updated: August 5, 2009 10:59 EDT