Warming signs add up, experts say
 

BY BOB BERWYN
summit daily news
Summit County, CO Colorado

March 8, 2007


SUMMIT COUNTY — Rising global temperatures could play out in significant ways in the Colorado High Country, with the effects ranging from earlier snowmelt and a less reliable water supply to a loss of the spectacular alpine scenery that is fundamental to the state's tourism economy, a panel of experts said Thursday evening in Frisco.

The climate change forum, presented by Our Future Summit, included a presentation from Denver Water resource manager Marc Waage, who said that even a moderate two-degree rise in temperatures could result in a six percent drop in water supplies and a 12 percent increase in demand.

Waage said those numbers were based on a simplified vulnerability study recently completed by Denver Water, but even if the figures aren't spot on, the state's biggest water supplier is looking at ways to reduce its vulnerability to the impacts of global warming.

“If the pie shrinks, our piece is most vulnerable,” Waage said.

For one thing, planners are trying to break the habit of relying on historic data to make plans for the future, he said. Resource managers have traditionally based their projections on data from past years, but with the uncertainties stemming from climate change, that approach may not work.

The two degree increase in temperatures used in the Denver Water study may be the best-case scenario for the Rocky Mountains. Some projections included in the recent international report on global warming show winter time temperatures in the West climbing by six to eight degrees during the next 50 to 100 years, with summer temperatures edging up seven to nine degrees.

And warming temperatures during the past few decades have already contributed to a measurable change in the timing of snowmelt and spring runoff, said U.S. Geological Survey researcher Dave Clow, outlining a pilot study based on data from 72 automate SNOTEL measuring stations and 40 streamflow gauges.

According to Clow, The average change in the onset of snowmelt has been about .5 days per year, or about two and a half weeks during the 28-year period covered by the study. Warmer springtime air temperatures are the primary driver of the changes, Clow said.

Those findings tied in neatly with data presented by climate researcher Klaus Wolter, who is refining statistical methods for analyzing climate trends. Among other research, Wolter has pinpointed a marked warming trend in Colorado's north-central mountains, with warming most apparent during the spring months.

Temperature maximums don't seem to be quite as affected as minimum temperatures. In other words, it's not getting nearly as cold as it used to in the area, he said.

Wolter also presented information from the recent Intergovernmental Panel on Climate Change (IPCC) report that tries to show how different things affect greenhouse gas concentrations; jet contrails, for example, appear to have been discounted as a significant factor. Trying to sort through the science and develop reliable data sets is crucial to identifying potential red herrings in the climate change debate, he suggested.

The warning signs include a shrinking snow cover in the northern hemisphere.

“The absence of snow could exacerbate the warming trend,” Wolter said. “There is a very intimate coupling between snow cover and temperature.” The volume of global ice is also diminishing, and the rate of that change could still result in some unexpected consequences, he added.

“There's room for surprises,” Wolter said, adding that about 90 percent of the scientists think it will be wetter in the winter and drier in the summer.

Tom Easley, of the Rocky Mountain Climate Organization, outlined how his organization is developing a climate action plan for Colorado. The first step is an emissions inventory and forecast, he said.

The group hopes to complete its plan by the end of the year, and Easley said the Ritter administration appears to be receptive to turning those recommendations into legislative action next year.

While the challenge is global in scale, taking action in Colorado is important in the scheme of things, he added, explaining that the state produces more greenhouse gases than all but 38 countries in the world.

The western U.S. could take the brunt of the warming, with average temperatures climbing by almost another two degrees by 2040. That could mean 24 percent less snow in the region and 36 percent less storage in the Colorado River Basin.

The good news, according to Easley, is that many of the actions required to reduce greenhouse gas emissions have positive side effects, including the creation of new jobs, less sprawl and lower energy costs for consumers.

“It's very important we take this seriously. We have a lot at stake,” said Frisco Town Councilmember Tom Looby, who moderated the panel. The hope is the forum will spur a wider community dialogue on the issue, he added.

Photographer and conservation advocate John Fielder ended his presentation with an emotional plea to act now to save Colorado's spectacular alpine scenery, describing how, in the course of his work, he's already noticed forests creeping up higher into the tundra and alpine zones.

“It could be gone by 2050 as the subalpine zone moves higher,” Fielder concluded.

Bob Berwyn can be reached at (970) 331-5996, or at bberwyn@summitdaily.com.


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Comments and questions can be directed to:

 Howard Hallman, PO Box 209, Frisco, CO 80443

970-468-9134 or hhallman@ourfuturesummit.org