A drier future?
post independent staff
GLENWOOD SPRINGS – A panel of experts agreed last week that the Earth is warming, that the warming trend is due in some part to human activity, and that it represents potentially dire consequences for Colorado’s recreation-based economy.
But just what those consequences will be remains as much a mystery as the fact that, despite global warming, Colorado’s last two winters were colder than usual.
The panel of six spoke to a small audience at the Glenwood Springs Community Center on Thursday.
“I think we demonstrated that there will be an impact,” said David Dittloff of the National Wildlife Federation, one of the sponsoring organizations, after the gathering had ended. “As for the specific type of impacts we can expect, it’s still a little too early to say.”
Climatologist Joe Barsugli of the National Oceanic and Atmospheric Administration (NOAA), who has been studying climate changes for 20 years, told the audience that the recent cool winters in Colorado are not, by themselves, easily explained.
But, he said, cooler temperatures here and in other isolated parts of the globe do not alter the facts: As a whole, the globe was an average of 1.4 degrees Fahrenheit warmer in the year 2000 than it was 150 years earlier; the oceans have risen by roughly half a foot over the same time period; and the carbon dioxide content of the atmosphere has increased from 270 parts-per-million in the mid-1800s to more than 380 ppm today, which experts believe is acting like a blanket wrapped around the planet.
Current projections show Colorado warming by about 2.5 degrees F by 2025, and by 4 degrees F by 2050, using temperature records from 1950 to 1999 as a baseline, Barsugli reported.
“You’re going to get summers that are warmer than most of the summers we’ve experienced in the past,” he predicted.
But, he added, predicting rainfall and snowfall is much more difficult. Roughly a fifth of Colorado’s annual average rainfall of 16 inches, Barsugli said, ends up in the state’s rivers and waterways – the rest either evaporates or is transpired through plants.
If snowfall and rainfall drops off as expected, he said, “We may see droughts like we saw a thousand years ago, when there were longer droughts.”
In addition, there likely will be warmer and drier shoulder seasons in the spring and fall, leading to shorter ski seasons.
“Summers are projected to warm more than winters,” states a fact sheet put out by the Colorado Water Conservation Board and other organizations. Although the state’s altitude and generally cool temperatures may protect it from the worst effects of global warming, Barsugli said, it is likely Colorado’s soils will get drier, its reservoirs levels will drop, and its streamflows will decrease.
According to Eric Kuhn of the Colorado River Water Conservation District, state water watchers started worrying about water shortages due to global warming as long ago as 1986.
But, he continued, uncertainty about the validity of scientists’ predictions and a “political partisan divide” about the issue may hamper Colorado’s ability to respond to what experts increasingly view as unarguable.
He said studies now show appreciably diminished flows in the Colorado River in the coming decades, which implies similar drying effects in tributary waterways and the High Country in general.
Tom Schreiner, Colorado Division of Wildlife climate coordinator, said his agency is “trying to come to grips” with the situation in terms of the impacts on everything from hunting and fishing to rafting, not to mention a rising frequency of wildfires that destroy habitat and endanger wildlife as well as human life.
“There’s still a good amount of uncertainty” about the issue, he said.
Ken Strom of the Audubon Society Colorado said bird surveys indicate many species are moving northward from their historic “centers of abundance,” meaning areas where birds are reported in the highest numbers every year.
This pattern of relocation, he said, is happening across short distances for some species, but across hundreds of miles for other species.
“What we’re seeing is that birds are moving … all across North America,” Strom said, and the experts believe it is because of warming temperatures at lower latitudes.
As for the rafting industry, Ken Murphy of Rock Gardens Rafting reported there are ups and downs to changing conditions.
“Our trips are getting shorter and shorter” due to falling water levels,” he said. “We don’t have the same flows.”
On the bright side, he added, the season starts earlier than it once did, and by switching to smaller rafts the industry has so far been able to keep its customers happy and its revenues steady.
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