From The Summit Daily News (Kevin Fixler):
[Brad] Udall, a distinguished climate researcher, was on hand as the keynote speaker for the 24th annual Summit County State of the River meeting hosted by the Blue River Watershed Group and Colorado River District. The yearly gathering to discuss the season’s snowpack, local reservoir operations and health of the headwater region’s water bodies was highlighted by Udall’s research on how rising temperatures are a contributing factor to significant reductions in river flows.
The study, conducted with Jonathan Overpeck, a renowned hydrology expert and the director of the University of Arizona’s Institute of the Environment, points to climate change today producing below-average flows out of the Colorado River. From 2000 to 2014, it resulted in 19 percent less water than the 100-year average, despite relatively consistent precipitation levels, as also ultimately occurred during the most recent winter after some slow beginnings.
“As many of you know, we started out the year in a very poor way and all of a sudden it went like gangbusters in almost the whole Rocky Mountain region in December into January,” said the Colorado River District’s Jim Pokrandt. “Then the spigot turned off.”
Those massive snowfalls in December and January created hope of an especially strong water year, but an abrupt drop-off thereafter soon resulted in below-average totals approaching April. As of May 1, snowpack in the Upper Colorado River Basin was only just ahead of a typical year following disappointing precipitation in the months of March and April. The late-April snowstorms rescued what would have otherwise been a below-average snowpack.
Across the state, totals are now in line with average years, but it’s a matter of arguing over what could have been. Udall thinks his research definitively shows the culprit.
“It doesn’t take a lot to figure this out,” he said. “It’s due to higher temperatures. This does not bode well for the future.”
Colorado recorded its hottest March on record based on 123 years of data, at almost 9 degrees Fahrenheit higher than normal. Whether you believe it comes down to the unseasonable heat — or what may be causing it — the fact is the snow rarely arrived to Summit County during that month.
The science is more complex than warmer temperatures simply preventing precipitation from transforming into snow, though conditions also need to be right for that to happen. The hydrologic cycle dictates that the atmosphere holds on to 20 percent more water for every 5 degree increase in temperature. Evaporation, where liquid is turned into vapor, is taking place as the thermometer rises as well. A similar process happens with plant life that prevents water molecules from ever touching the ground, and — also combined with a lengthening growing season due to climate change — eventually less water is forming in our major waterways.
That all said, these types of water levels on the Colorado River are not unprecedented, with the 15-year drought between 1953-67 as a similar period. Those lower flows were based on a lack of precipitation, though, not heightened temperatures as they are presently. Add in growing demands on the river in what several speakers last week called “a pretty good water year,” with precipitation historically flat as well as swelling populations, and suddenly we’re staring down the subsequent depletion of a stock used in Colorado for drinking, recreation, crop irrigation and export to several other western states rooted in federal law.
“We’re in a long-term situation where demand on the resource exceeds the supply,” said Eric Kuhn, general manager of the Colorado River District.
Udall remains optimistic we can still dig our way out of this hole, to put water levels on crucial western rivers like the Colorado back where they should and need to be. It will require a concerted effort, he said, to reduce greenhouse gases through a paradigm shift away from past methods that are outdated, and by way of current technologies. The longer we wait, he added, the bleaker our water future will be.
“It’s warming,” Udall said of the climate in his closing remarks. “We’re the cause. It’s serious. We’re sure, and we can fix it.”