With year-round wildfire season, record dry and hot weather, flooding and insurers pulling out, it can feel like the climate in Boulder is becoming increasingly inhospitable.
Colorado has already warmed 2.5 degrees Fahrenheit since 1980, and most climate models estimate this could rise to 6 degrees by the mid-century. Yet Colorado — and Boulder — have certain factors going for them in terms of resilience to climate change in the near term. The long-term outlook, especially for drought and wildfire, is not as good.
“Even though there are elements of climate change that worry me here, I’m fairly comfortable living here for the time being.” said Peter Goble, a climatologist with the Colorado Climate Center at Colorado State University, who lives in Berthoud. “I would choose here over most places.” If he were starting from scratch, he added, the Front Range wouldn’t be his top choice.
“If I were picking a place to live in the U.S. just based off natural resilience to climate change, I might go with the upper regions of New England or the Upper Midwest, like Wisconsin or Michigan.”
Goble explained that Colorado’s altitude provides some protection against the worst effects of climate change, particularly extreme heat. This doesn’t mean the area won’t get hotter. Climate models show more of Boulder’s summer days will reach above 90 or even 95 degrees, with those hot days likely extending further into August and September than in the past. But the 115-degree days of Arizona are unlikely to reach Boulder due to its elevation.
Extreme heat events, like the recent scorching temperatures in the Southwest, often occur when a high-pressure system traps a thick layer of hot air in the atmosphere over a region. Typically, the hot air would rise up and dissipate into the upper atmosphere, but in situations like those in Arizona, it becomes trapped with nowhere to go. In Boulder, our proximity to higher elevations and cooler air makes a difference. When surface air temperatures rise while cooler, thinner air lingers above, the atmosphere can become unstable, triggering thunderstorms and bringing cooler air down to the surface.
“Once temperatures start pushing a hundred on the Front Range, unless we’ve got really dry air and a really nice high pressure air mass, it’s really hard to build that kind of heat without setting off thunderstorms,” Goble said.
Boulder also benefits from cooler nighttime temperatures, giving it a significant advantage over many other places not only in the country, but globally, according to Goble. Rising nighttime temperatures are dangerous because heat-stressed people can’t cool down, increasing the risk of heat-related deaths. We also have access to the mountains for a heat escape. Dillon in Summit County, Goble noted, still hasn’t seen a 90-degree day.
It’s not all good news, though. Drought and wildfire are Goble’s top concerns for living along the Front Range as climate change worsens from continued fossil fuel emissions, with air quality impacts from wildfires adding to the list of concerns.
Colorado sits in a wishy-washy position in climate models predicting precipitation changes. While the Southwestern United States is expected to get less precipitation and the Northeast more, Colorado’s overall precipitation might not change much, but its patterns could shift significantly.
Goble explained that this could manifest as long stretches of no precipitation — like this year’s record-dry May and June — followed by intense rainfall that may have been spread over a longer period of time in the past. These dry stretches will likely continue to intensify wildfire season, aided by hotter temperatures that increase the evaporation of moisture from the landscape. At the same time, extreme precipitation events could lead to more flooding, especially for those living near canyons and waterways. When the landscape is dried out, it becomes less absorbent, causing the first burst of rainfall after a drought to run off the ground much like it would off asphalt.
Boulder’s climate future could also bring more large hail, according to Goble, which he said is troubling for an area already known as part of “hail alley.”
Predicting what, exactly, severe weather will look like in Boulder in 50 or 100 years is difficult, because some factors that contribute to severe weather are increasing, while others are decreasing.
With thunderstorms, for instance, the growing difference between surface and higher-altitude temperatures could lead to more violent storms over Boulder. But these storms also rely on “wind shear,” which refers to winds at varying altitudes moving aggressively in different directions. Some climate models suggest that climate change is making upper atmospheric winds less intense, potentially offsetting the increased volatility from warmer surface temperatures.
There’s also the uncertain influence of the North America monsoon. Climate models are divided, with some predicting that the southwestern Colorado will get wetter and others showing it will become drier. There’s also a chance that these monsoons could reach up to Boulder.
“I don’t think we have a good handle on what warming means for that circulation,” Goble said.
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