NZealand glaciers retreat due to global warming: scientists*

WELLINGTON, Nov 19 (AFP) Nov 19, 2007

New Zealand's largest glaciers are retreating fast in the face of global
warming and could disappear altogether, scientists said Monday.

A report by the National Institute of Water and Atmospheric Research
(NIWA) said the volume of ice in New Zealand's Southern Alps had shrunk
almost 11 percent in the past 30 years.

More than 90 percent of this loss was because the 12 largest glaciers in
the mountain range were melting due to rising temperatures, NIWA said.

The glaciers have passed a threshold, causing the ice to collapse and
creating large lakes at their base, the report said.

"The 12 big glaciers with these pro-glacial lakes have passed a tipping
point," said NIWA's principal scientist Jim Salinger.

"It is not yet clear whether the glaciers will disappear completely with
future warming, but they are set to shrink further as they adjust to
today's climate," he said.

"And it is already clear that they will not return to their earlier
lengths without extraordinary cooling of the climate, because the large
lakes now block their advance."

Tasman Glacier, the longest in New Zealand, is now about 23 kilometres
(14 miles) long. A five-kilometre lake has formed at its base in the
past 30 years. In the 1880s, the glacier was 28 kilometres long.

But increased rainfall -- which falls as snow and feeds the higher
reaches of the glaciers -- on the western side of the Alps has meant the
results for smaller glaciers on that side are mixed, NIWA said.

These ice sheets advanced during most of the 1980s and 1990s amid
periods of higher rainfall.