Tom Compton has noticed a shift in Southwest Colorado’s climate.
For decades, he ran the Compton Cattle Co. near Hesperus. While working on the land, Compton saw the subtle effects of the changing climate.
“Over the last 20 years, things have begun to get a little drier,” he said. “We don’t get the snowpack every year like we used to get.”
“It’s been relatively slow. It’s not been a huge change (or) an abrupt change,” he said.
The National Oceanic and Atmospheric Administration’s most recent climate normals reflect what Compton has seen. NOAA’s new normals show that Southwest Colorado has largely gotten warmer and drier as climate change impacts the region.
Climate normals are crucial tools for scientists, combining decades of data to help them understand weather patterns. They also serve as an indicator of climate change.
Durango’s average temperature has increased 0.5 degrees Fahrenheit and precipitation has dropped approximately 1.5 inches, according to NOAA’s new normals, which capture nationwide averages in temperature and precipitation over a 30-year period.
Changes in temperature and precipitation are measured by comparing NOAA’s two most recent 30-year normals from 1991 to 2020 and 1981 to 2010.
In Cortez, the average temperature has jumped by 0.7 degrees and precipitation has decreased by 0.75 inches.
Ouray has gotten 0.5 degrees hotter on average and about half an inch drier.
And the average temperature in Creede in Mineral County has increased by 0.7 degrees, while precipitation has also slightly increased by about 0.2 inches.
NOAA’s new normals show the Southwest U.S. as a region is overwhelmingly getting warmer and drier.
“The warming is happening pretty much everywhere. The precipitation changes are more variable,” said Russ Schumacher, an atmospheric scientist with Colorado State University and the Colorado state climatologist. “In Southwest Colorado, (there has) certainly been a drying trend in recent years.”
NOAA released its new climate normals in May 2021. Every decade the federal agency and its National Centers for Environmental Information update 30-year averages for measurements such as temperature and precipitation.
“A climate normal is a value of climate like temperature (or) precipitation that best represents the situation on a given day of the given month for the current climate,” said Michael Palecki, a physical scientist with NOAA and project manager for the agency’s recent normals.
Put simply: “It’s a baseline for putting today’s weather in proper context,” he said.
Whenever a meteorologist on TV says the temperature, precipitation or snowfall is above or below average, they are comparing the weather to NOAA’s climate normals.
Creating these normals is a complex process that requires data collected from thousands of weather stations and citizen scientists over the course of decades. Scientists must then combine the data and use complicated statistical techniques to fill in the gaps, account for outliers or anomalies and then finally calculate each average.
Collecting, compiling and standardizing the data takes most of the decade.
“Once we pull the trigger, it only takes a few weeks to actually create the normals,” Palecki said.
NOAA calculates annual, seasonal, monthly and daily normals for temperature and precipitation, as well as the normals for growing seasons and growing degree days, metrics that are often used by farmers to plan their planting.
“We have literally hundreds of variations on these variables,” Palecki said.
“For each hour of each day of each year for certain locations in the U.S., we can tell you what the chances are for there to be cloudiness or wind,” he said.
The information is critical for many industries, from broadcast meteorology to agriculture to the energy industry.
Climate normals guide the design and construction of houses and dictate drainage for streets and parking lots.
The retail industry relies on climate normals for the timing of seasonal clothing and the travel industry uses them to help people plan trips, Palecki said.
“It really is widely used information,” Schumacher said.
While climate normals are best used for understanding how today’s weather compares to the most recent 30-year average, they are also critical for climate scientists studying and informing the public about climate change.
Climate normals do not reveal long-term warming trends in temperature or precipitation; NOAA relies on much longer data sets from 1901 to 2000 to track those.
Instead, they show the effects of climate change and confirm the accuracy of the models that researchers use to predict future climate change.
State climatologists like Schumacher rely on normals to create visualizations that highlight climate change. Many of the maps and charts that they make comparing the weather from month to month or comparing climate across the state use the averages from climate normals.
Climate scientists can use these visuals in conjunction with data that shows long-term climate trends to paint a clear picture of the threat that climate change poses.
“We will compare the last month’s temperatures to that 30-year baseline of the climate normals, but also try to put it into the terms of a percentile (like) the top 10% of warmest months,” Schumacher said. “That helps to put it into that longer-term climate context.”
More important, climate normals deliver evidence that the models used by scientists are accurate.
“(Normals) provide proof of the climate change that we expected from looking at climate models that have been run over time,” Palecki said. “… We are confirming that the models are giving us a pretty accurate picture of the effects of climate change.”
Without these normals, scientists may never know if their models correctly predict climate change, limiting the power of a crucial tool for policymakers and other decision makers.
The climatic changes NOAA’s new normals document are often subtle, but those changes have a direct impact on those who work with the land.
While Compton has left the cattle business, the progressively drier and warmer climate of Southwest Colorado altered how he conducted his operations.
“You’ve got to change the way you manage the land,” he said.
To adjust to the changing climate, Compton used a modified form of range management, dividing up his land and rotating his cows. He constantly looked for ways to improve his water infrastructure so enough was making its way into the soil.
“We always tried as best we could to set aside a pasture every year that we didn’t graze,” he said. “… That worked out fairly well, but it turns out that there is nothing that beats snowpack and rainfall and it’s just so variable here.”
NOAA’s new climate normals highlight the challenge that many ranchers face. Even as they look ahead to ensure the long-term success of their operation, the climate changes every decade.
“I can develop a plan for how we’re going to manage next year and I can develop a plan for how we’re going to manage (the next) five, six, seven years, but then I have to begin to think about what’s my Plan A, Plan B and Plan C,” Compton said. “If I don’t have the moisture next year or in five years, I have to plan accordingly.”
Amid new climate normals, ranchers must remain adaptable, he said.
“I think I went to school one time and the teacher said, ‘You have to adapt, migrate or die,’” Compton said. “At the time, I didn't want to go anywhere and I wasn’t ready to die, so I tried to adapt.”