Fourth footnote

It is, if you will, a top-down view of the already-present effects of global warming.

Mountaineers are bringing back firsthand accounts of vanishing glaciers, melting ice routes, crumbling rock formations and flood-prone lakes where glaciers once rose.

The observations are transforming a growing number of alpine and ice climbers, some of whom have scientific training, into eyewitnesses of global warming. ...

"I personally have done a bunch of ice climbs around the world that no longer exist," said Yvon Chouinard, a renowned climber and surfer and founder of Patagonia, an outdoor clothing and gear company that champions the environment. ...

Already, Switzerland's Matterhorn had to be closed to some climbing at times because of recent summer rockfall attributed to global warming, and its Great Aletsch Glacier — Europe's largest — has retreated a couple miles from its peak of 14 miles in length in 1860. The Swiss Alps' icy soil that glues its rock faces together is thawing, causing instability.

At Montana's Glacier National Park, glaciers are vanishing like the storied snows of Africa's Mount Kilimanjaro. In South America, the great ice fields of Patagonia in Argentina and Chile are shrinking; Bolivia hopes to keep its only ski area open by using artificial snow as the Chacaltaya Glacier fades.

The glacier from which Edmund Hillary and Tenzing Norgay made their first ascent of 29,035-foot Mount Everest in 1953 has retreated so much that mountaineers now walk hours longer to reach it.

A mile-long lake replaced the glacier at 20,305-foot Island Peak in Nepal's Everest region.

"So who ya gonna believe," sneer the skeptics. "Me or your lying eyes?" Fortunately, it seems that fewer and fewer people are listening.