From The Colorado Sun (Michael Booth):
Following are just a few of the ways “climate change now” made its full force known in the Rocky Mountains this year and showed its impact on everyday life.
Record high heat changes Colorado school life, for kids and parents
Seventeen Denver Public Schools closed or sent students home early Friday because of heat, underlining the fact that many school buildings still lack modern air conditioning despite years of bond issues and calls for renovation.
In a note sent to parents last week, Steele Elementary’s principal warned the school would shut at noon Friday, and apologized for the late notice for those needing child care during the workday. “Weather forecasters say temperatures in Denver tomorrow and Friday will hit 97 degrees,” Principal Marti Rosenberg said. With Thursday setting a record high, she added, “the consecutive days of heat will make it challenging to keep temperatures at a reasonable level on Friday.”
For those dismissing a Sept. 10 heat blast as typical for Colorado, 9News meteorologist Cory Reppenhagen put together an astonishing 2021 summer compilation: Four Colorado weather stations recorded their hottest average summer temperatures on record. Steamboat would have made it five, but was off by one-tenth of a degree. Central Park station had its second hottest summer on record. Denver’s annual heat streaks of 90-plus have doubled in length since 1970, to 12 days.
Until about 1900, Reppenhagen’s charts show, a roughly equal number of daily high and low records would be broken in Colorado each year. The scales tipped then. So far in 2021, eight daily highs have been broken, and only one low.
A draining Colorado River hits recreation life and the economy
When the federal government pulled the plug on Blue Mesa Reservoir to save the Colorado River and Lake Powell downstream, the big Gunnison-area bathtub drained so far that the boats had to pack up and go home.
Federally-managed Blue Mesa on the Gunnison River was already low from two decades of western drought when managers announced in July they would partially drain the lake, plus Flaming Gorge and Navajo Reservoir, in order to protect the hydroelectric power pool at Lake Powell. The drought had so severely dried up Powell that the massive generating dam there would stop without help from upstream.
By September, Blue Mesa’s draining pool left boats literally high and dry. The National Park Service told the marina concession to cut six weeks from its five-month season, before the floating dock hit lake bottom.
Vega State Park, near Grand Junction, also closed its main boat ramp at the end of July, a least a month early, citing low water levels at the lake part way up the Grand Mesa. Earlier in the summer, Mesa County’s largest municipal water provider said it would take the unprecedented step of using Colorado River water directly in order to protect water levels at cleaner reservoirs it owns on the shoulders of Grand Mesa.
Cause and effect: “Because of changes in greenhouse emissions, we see more droughts in the American West,” said Iglesias, the EarthLab researcher. Researchers who used to shy away from pinning individual droughts on climate change have by now “stopped talking about it because it’s become so obvious that it’s boring,” she said…
Morning coughing with the morning coffee brought 2021 hazards home
If you could hang on to the orange-tainted, smoke-enhanced sunsets, the summer days of 2021 redeemed themselves a bit. But only after a full day of coughing and wheezing from distant wildfire smoke and Front Range-generated ozone, which you were not just imagining.
Massive fires in California, Oregon and Canada — still burning, by the way — sent plumes of smoke across Colorado, with smoke forecasts becoming a staple of commercial TV weather segments. The smoke raised levels of particulate matter in Front Range skies, referred to in public monitoring as PM2.5. Doctors at National Jewish Health and other medical experts warned all summer that those with asthma or other respiratory sensitivity should wear N95 masks outdoors or stay indoors on the worst days.
Meanwhile, existing auto and oil and gas pollution that produces Front Range ozone was baked into a bigger problem by the 2021 heat wave. Ozone is likely made worse by the imported wildfire smoke as well, though researchers haven’t yet concluded how much.
The result was by far the highest number of ozone action-alert days declared by the Colorado Department of Public Health and Environment since the EPA ratcheted down allowable ozone limits in 2016. The state issued 65 alerts over their summer reporting period, up from 43 in 2020 and well past the previous high of 52 days in 2018.
National Jewish researchers capped late summer with a new study directly attributing climbing ozone levels to higher temperatures from climate change. The study, published in Nature, also said that the impacts of higher ozone are much worse in areas of the Front Range with higher numbers of Hispanic residents and low-income households. The study concludes that the heat-caused rise in ozone has delayed the Front Range counties’ coming into compliance with EPA limits by two years. Metro planners now have to agree on policy changes that could lower pollution in order to reach EPA compliance.
“The ozone climate penalty can be expected to grow over the next several decades,” the study says. “We found that residents of the Front Range are already affected by climate change through higher temperatures and higher ozone levels, and that the resulting ozone burden is already falling disproportionately on historically disenfranchised and frontline communities.”
More bad news, Colorado: This could be just the beginning
There are lifetime droughts, and then there are geologic-time droughts. Matthew Lachniet, at University of Nevada, Las Vegas, studies the latter, and the stalactites and stalagmites tell him stories you may not be ready to hear.
Human-kept climate records detail the past 100 to 150 years, Lachniet notes. Tree rings, an important climate and biology tool, can take scientists reliably back 1,000 years or more. Lachniet is a “paleoclimatologist,” studying the growth of drip-rocks in caves over tens of thousands of years. A stalactite dripping from a cave ceiling charts the passing of floods and droughts through water seepage, taking a thousand years to grow an inch.
What Lachniet has seen in caves in the Southwest is evidence of a painful drought stretching from 9,000 years ago to 5,000 years ago. Four thousand years of dry winters.
“We can see that aridity can extend for not just decades, but centuries, and potentially even millennia,” Lachniet said. And that’s the record before humankind made things worse by adding uncontrolled CO2 into the atmosphere for more than a century.
The cave records underline the recent folly of federal water management officials helping to write Colorado River compacts that distribute water — to 40 million people in seven states — based on river flows in much wetter than average years, Lachniet added.
“We have to plan for the possibility that flow in the Colorado River is going to be far below the 16 million acre-feet that we’re allocating, maybe as low as 12 million acre-feet, or potentially lower,” he said.