Glaciers melting in a warming world

UP and down the icy spine of South America, the glaciers are melting, the white mantle of the Andes Mountains washing away at an ever faster rate.

“Look. You can see. Chacaltaya has split in two,” scientist Edson Ramirez said as he led a visitor up toward a once-grand ice flow high in the thin air of the Bolivian cordillera.

In the distance below, beneath drifting clouds, sprawled two-mile-high La Paz, a growing city that survives on the water running off the shoulders of these treeless peaks.