Cargo limits and other challenges (and some benefits) of rising temperatures
by Allen Best
Rising 2 degrees Fahrenheit over the last 30 years, the average annual statewide temperature in Colorado will rise 2.5 to 6 degrees more in Colorado during the next 35 years, according to climate change models.
How will that impact Colorado, including its mountain towns?
A new report, “Colorado Climate Change Vulnerability Study,” digs broad and relatively deep to answer that question, coming up with answers that go far beyond the traditional answer about shortened ski season.
Consider, for example, that hot air is less dense, which reduces mass flowing over the wings of airports to create lift. The planes can carry less weight, including fewer passengers, squeezing profitability.
Because of this, runways at airports serving the Vail and Aspen areas have each been lengthened by 1,000 feet in recent years, to enable expanded use during summer months.
Denver International already has the world’s longest public runway, but could face the same squeeze from rising temperatures, with “summer cargo losses as high as 19 percent by 2030 due to increased temperatures and water vapor in the atmosphere,” says the report, which was ordered by the Legislature and administered by the Colorado Energy Office.
Might technological advances overcome this limitation? Possibly. Airplanes have become far more fuel efficient in recent years, for example. But it’s unknown.
Streets and highways might also be taxed.
“Road materials have a limited range of that tolerance, and road buckling occurs with sustained temperatures above 90 degrees Fahrenheit,” the report says. “Bridges are particularly vulnerable to high temperatures, which stress bridge integrity. Extended periods of extreme heat shorten pavement life and cause bridges to expand, with negative economic impacts.”
Water infrastructure will also be taxed by climate change. Our reservoirs and other delivery systems were created for the 20th century climate. In the 21st century, we could eventually have more snow and rain, at least in places. Climate models remain fuzzy. But rising temperatures alone have huge repercussions. Spring during the last 30 years has sprung, on average, one to four weeks earlier.
Runoff by mid-century could come as much as six weeks earlier. Longer, hotter summers will strain capacities of our reservoirs. We risk more severe droughts. Storage will become even more important.
Enlargement of Gross Reservoir, located in the foothills southwest of Boulder, can also be seen, at least in part, as a response to the potential for longer summers and more intensified droughts. The larger reservoir will hold expanded diversions from the Fraser and Williams Fork valleys on the Western Slope.
Ski areas and outdoor recreation will also have adjustments. Colorado’s high elevation and cold temperatures buffer some effects of climate change, the report notes, at least in the short term. But the window of profitability will be squeezed, and use of snowmaking to ensure sliding surfaces for early-winter crowds will be challenged by warm temperatures.
One study from Aspen is noted: resort managers need at least 12 hours per day at or below the 28 to 32 degree Fahrenheit in order to engage in effect operations.