Study: Global warming will have serious effects in Aspen

Aspen is headed toward warmer, shorter snow seasons, according to preliminary findings of an ambitious study on global warming's local effects.

Advanced computer modeling projects a half-degree centigrade increase in 20 years and a 2- to 4-degree increase by the end of the century.

The earth has already increased half a degree centigrade in the past century, which has contributed to three more frost-free weeks a year in Aspen. A two-degree increase in the next 50 years would mean an additional three full months of frost-free weather.

Dr. Gerald Meehl, senior scientist at the National Center for Atmospheric Research, presented the findings Thursday.

Meehl said there is an "unambiguous increase in temperature by the end of this century. Aspen will be warmer, with a shorter snow season, especially at lower elevations. Higher elevations are less affected. As you go higher it's colder; that's good news."

Meehl said another half-degree of warming is unavoidable, even if greenhouse gases were stabilized today.

"Every day that goes by, we're committed to even more global warming in the future," he said.

Meehl said the computer models in the study match up with theories regarding global warming.

"This is pretty much without dispute," he said, using a laser pointer to show significant warming in the last 20 years. "Virtually every glacier in the world is retreating."

Advances in computer modeling have made it clear the warming

is attributable to human activities. When scientists plug in data concerning volcanic and solar activity, the computer model is similar to what actually happened in the 20th century, until the 1970s. When they add the data regarding greenhouse gases such as methane and carbon dioxide, the models show the warming.

When the computer modeling first started, information was not specific about a place as small as a city. Now supercomputers can pinpoint information about localities.

The Aspen Global Change Institute has assembled the team of scientists, including Meehl, as part of Aspen's Canary Initiative, a program to reduce Aspen's contribution to global warming and to lead by example.

The final study will attempt to estimate snowpack for future ski seasons, average depth and quality of snow. The findings of the study will drive policy decisions in the area and, organizers hope, influence other communities to look into how their areas will be affected. A final report to the city is due at the end of March.

"Aspen is proactive and farsighted to do something like this," Meehl said. "This is a real political issue. Most of us have the feeling that our job is to do the best possible job on the science. There is a group of people out there who make it their business to keep it controversial."

Joel Stonington's e-mail address is jstonington@aspentimes.com