Southwest Colorado is hotter than it once was, and experts say they have data and anecdotal evidence to prove it.
Global average temperatures peaked worldwide in July, making it the hottest July and the hottest month in recorded history, according to the National Oceanic and Atmospheric Association. On Colorado’s Western Slope, the average temperature has increased at least 2.7 degrees since 1895, based on 123 years of weather records, NOAA scientists estimate.
Darrin Parmenter, director for the Colorado State University Extension Office in La Plata County, said the region’s average low temperature during the winter – a measure the United States Department of Agriculture calls “hardiness” – has increased significantly.
The hardiness statistic is measured on a scale of 1 to 13; the higher the number, the warmer the average low temperature. In the 1990s, Parmenter said Durango was classified in Zone 4. The city is now in Zone 6.
“It’s crazy, horticulturally (speaking),” he said.
A Washington Post investigation and analysis of nationwide climate found Southwest Colorado is just south of one of the fastest-warming regions in the country. Grand Junction; Moab, Utah; and Montrose form the corners of a triangle of average annual temperature increase of more than 2 degrees Celsius, or 3.6 degrees Fahrenheit, since 1895.
Global climate data may be difficult for people outside the science community to appreciate, said Heidi Steltzer, professor of biology and environmental science at Fort Lewis College. Humans don’t experience time on the scales climate is measured.
“We experience local conditions, we don’t experience global means,” she said. “So when we read and hear about global temperature means, we say, ‘That’s not my world.’”
But in the 25 years she has studied Colorado, 10 of which were spent in the Southwest, Steltzer said “the summer is not the same anymore.”
Colorado has historically had shorter growing seasons because of extended snowpack, and high-snow winters in the 1930s through the 1960s typically led to a lot of rain in the summer, Steltzer said. The 2018-19 winter snowpack filled the San Juan Mountains and nourished the San Juan Basin much like it did in the mid-1900s.
Steltzer said she was excited for the opportunity to study the effects of late snow in the Alpine environment – she hadn’t seen snow like there was this spring in more than 20 years living in Colorado and studying the Rocky Mountains’ climate.
But what she saw took her by surprise. The snow melted in the high country sooner than expected, she said. Her field work in the San Juan Mountains this summer showed that plants at high elevations are “experiencing drought conditions” despite snow burying the region late into the spring.
Steltzer suspects that below-average rainfall and higher average temperatures this summer may have robbed the high country of valuable water storage and replenishment. Both can be attributed to a changing climate, she said.
“When it’s warmer, more water will move from the Earth to the sky,” she said. “Warmer temperatures mean more water moves to the sky and is not available in the ground to fuel plant growth or move into aquatic systems.”
The discrepancy between winter and summer precipitation totals may also be attributed to a changing climate, Steltzer said. A rising global temperature creates “higher inter-annual variations,” meaning weather changes are more drastic in a shorter amount of time.
Durango City Council committed earlier this year to reduce greenhouse gas emissions citywide by 80% and encourage the use of 100% renewable electricity in Durango by 2050. That includes transforming public energy usage for government buildings and activities while also crafting policies to encourage renewable electricity for residents and businesses.
Dozens of #FridaysForFuture activists in Durango joined millions of people in thousands of towns in hundreds of countries for last week’s Global Climate Strike, demanding political action to address a changing climate.
Steltzer said “every degree matters.”
“Climate is the long-term pattern of temperature, precipitation; we have to have data,” she said. “But we have to have information over 50, 60, 100, 200, 1,000 years. We have to have more than what it was like today, what it was like yesterday, or even 10 years ago. Ten years ago isn’t what we look at when we try to understand change in climate.”
bhauff@durangoherald.com
