WITNESS - Global warming changes face of high Alps

By Sam Cage

TRIENT VALLEY, Switzerland (Reuters) - The Trient glacier looming ahead of me on a trek through the Alps this summer looked very different to the frosty heights that once provided ice for pastis drinkers in France.

Now the bare, eroded rock is testament to the ice's retreat under the warming effects of climate change.

In the 19th century up to a metre of ice was dug each day out of the glacier in southwest Switzerland, close to the border with France, and taken to Paris and Marseille for mixing in the anise-flavoured liqueur adored by the French.

The ice grew back overnight.

These days, Parisian cafe owners get their ice elsewhere.

"Nowadays of course the ice is way, way, way up. It's amazing how much has changed there," said Kev Reynolds, author of a guide to a Chamonix-to-Zermatt walking route, who has made several trips through the valley since the 1980s.

"Vegetation will soon be setting in down there, where a few years ago there was ice."

Switzerland has been particularly hard hit by a warming climate, with ski resorts often short of snow cover and potential water supply problems as sources melt away.