Contra Costa Times
New surveys from satellites and aircraft document an alarming acceleration in the melting of glaciers around the world.
The swift retreat of these great ice streams is helping to raise ocean levels and is threatening significant changes in human, animal, and plant lifesome good, but mostly bad.
Like a canary in a coal mine, the dwindling of the glaciers is visible evidence that the earth really is getting hotter.
"Receding and wasting glaciers are a chief telltale sign that global climate change is real and accelerating," said Jeffrey Kargel, a glacier expert with the U.S. Geological Survey in Flagstaff, Arizona.
Most of Earth's 160,000 glaciers have been slowly shrinking and thinning for more than a century as the climate warms up from both natural causes and human activity.
But scientists say the melt rate has accelerated dramatically since the mid-1990s, which was the hottest decade in a thousand years, according to data from ancient ice cores and tree rings.
A glacier in the Peruvian Andes, Qori Kalis, is losing as much ice in one week as it used to surrender in a year, according to Lonnie Thompson, a geologist at the Byrd Polar Research Center at Ohio State University in Columbus.
"You can literally sit there and watch it retreat," Thompson told a meeting of the American Association for the Advancement of Science.
"As the Peruvian ice fields disappear, sources of irrigation and hydroelectric power will dry up," he said. Other consequences include a more rapid rise in sea levels, speeding the flooding or even destruction of low-lying islands and coastal areas.
Glaciers are shrinking not only in area but also in thickness. In Alaska, they are losing an average of 6 feet (1.8 meters) of thickness a year, Anthony Arendt, a glaciologist at the University of Alaska, Fairbanks, reported last month in the journal Science. That's more than twice the annual rate observed from the 1950s to the mid-1990s.
By the middle of this century, the Rockies, the Cascades, and Glacier National Park will have lost almost all their ice, Kargel predicted.