Rocky Mountain Fires, Colorado
How climate change is contributing to a record breaking fire season in Colorado
I’ve seen it raining fire in the sky
Over the past few days, Colorado has witnessed an outbreak of wildfires unlike anything in the State’s history. West of Fort Collins, the Cameron Peak Fire blazed 15 miles to the East in a day, creeping towards the city and Loveland, Colorado. West-northwest of Boulder yesterday, the East Troublesome fire spewed pyrocumulous clouds that spilled over the Rockies and dirtied the skies over Denver. Fires West of Longmont and Northwest of Colorado Springs have similarly burst into existence in the Colorado Rockies, with the former prompting evacuation orders in North Boulder County. Across the Colorado front range, residents have reported ash ‘raining’ from the sky as the fires burn through the high forest of the Rocky Mountains.
When John Denver wrote of raining fire in the sky in the 1970s for his hit song “Rocky Mountain High”, he was likely unaware that humans had been taking steps towards making that cryptic vision a reality. In the century leading up to the release of Rocky Mountain High, the industrialized world had steadily increased it’s use of fossil fuels, an energy source with deadly side effects. In the five decades since, humanity has burned ~twice as much fuel as it had in the hundred years prior, and the Earth’s temperature has increased at a much more rapid rate. This warming’s devastating effects are beginning to make themselves apparent in Colorado in the form of raging wildfires.
You might say the fire was born again
It might surprise some to learn that the Cameron Peak Fire started burning in August. Astonishingly, it’s burned for ~2 months, and has seen some of its most rapid growth over the past week. Three days ago, the Cameron Peak Fire burned 20,000 acres in a day, racing it’s way to first place in the list of largest wildfires in Colorado history. It’s now burned an estimated ~199,000 acres and has vastly outgrown the old record holder, the Pine Gulch Fire from earlier in 2020. Consistent winds of 40–50 miles per hour fanned the flames of the Cameron Peak fire towards Fort Collins to push it past the Pine Gulch fire’s old record of 137,000 acres. Now it’s approaching a foreboding spot in history as the first 200,000 acre fire in Colorado. The same pattern of dry air and high winds prevailed across the state with other fires, covering most of Denver’s largest cities in the eerie glow of smoky skies.
When they first came to the mountains, the fire was far away
The recent rash of fires is largely unprecedented in Colorado history, and an unwelcome surprise for many recent migrants to the Rocky Mountain State. Based on the record from the 20th century, there would’ve been little reason to expect the megafires cooking the state currently. Before the year 2000, there had never been a wildfire over 30,000 acres in Colorado. Shockingly, Colorado’s 20 largest fires have all occurred in the last twenty years, with 2020’s Cameron Peak and Pine Gulch the two largest ever. The Mullen Fire, which sparked in Wyoming and dipped South into Colorado, has burned over 170,000 acres as well. Perhaps most astonishing has been the Cameron Peak Fire’s late season surge of >60,000 acres burned.
The image below attests to this unusual autumnal growth spurt. Of California fires that burned more than 10,000 acres from 1992–2015, not once had those fires sparked in October or later. The East Troublesome Fire bucked that trend by burning over 10,000 acres in the last few days. Most of Colorado’s larger fires start in June and July, with 2020 adding an additional three to the August tally. In short, it’s unusual to have such widespread and rapid fire growth this late in Colorado’s fire season.
Of course, Colorado isn’t the only part of the world experiencing record breaking fires. California just had its worst wildfire season in records going back ninety years. In September, 10% of Oregon’s population was under a simultaneous evacuation watch as wildfires bore down the western slopes of the cascades like Tolkien’s balrogs of Morgoth assaulting Gondolin. Siberia’s two worst wildfire seasons on the satellite record are this year and last, the Pantanal Wetlands in South America are presently ablaze and breaking records, and Australia’s record-breaking wildfires mercifully ended earlier this year. Which begs the question, what’s changed to supercharge all of these wildfires?
Much like the protagonist of Denver’s “Rocky Mountain High”, we’ve left yesterday behind us around the world. In the 12 months leading up to October, global average temperature was nearly 1.3°C above pre-industrial temperatures. Cooler temperatures of Winters past are part of a bygone era as we rapidly approach the ‘safe’ global average temperature aims of the Paris Climate Agreement of 2°C and the more aspirational target of 1.5°C. The record-breaking fires endangering towns and cities across the Western US in 2020 are one piece of evidence among thousands that we may have already left a safe climate behind us. At this point, it’s a matter of how badly we get burned.
They try to tear the mountains down to bring in a couple more scars
The coverage of Colorado’s wildfires historically largely neglected to cover the links between climate change and the ongoing record-setting fires, “The major television and print outlets largely ignored climate change in their coverage of wildfires in Colorado, New Mexico and other Western states,”. This year’s media coverage of western wildfires isn’t much better, with only 15% of televised segments mentioning climate change. In California, it’s pretty remarkable to leave climate change out of the reporting, with three heatwaves that broke temperature records coinciding with the outbreak of many of California’s largest wildfires in history. In Colorado, the links between a warmer world and it’s own record breaking wildfire season aren’t quite so obvious.
The image on the left is from a 2018 by Philip Mote and other scientists detailing the change in snow-water equivalent (SWE) across the American West. I’ve added overlaid the image with orange ellipses that show the areas in which many of 2020’s worst fires have occurred. In over 90% of studied locations, SWE declined, in some cases by as much as 80 percent! Unsurprisingly, warming up global land temperatures by ~1.8°C melts snow at the margins. When there’s less snowpack in mountain ranges, there’s also less snowmelt to provide water to plants. Those plants have adapted to the seasonal rhythms of freezing and melting over the last 10,000 years — the warming of the last 100 years and in particular the last 40 has produced warming that melts snow faster than trees can adapt to. Trees that grew accustomed to a certain amount of snowmelt now have to navigate hotter, longer summers with less water, drying them out over the course of fire season. The lack of water leaves them more vulnerable to catching fire when wildfires occur.
The problem of climate change induced snowpack declines isn’t strictly one of lost volume over time. In a study from two years ago, Xubin Zeng, Patrick Broxton and Nicholas Dawson demonstrated that snow season length has declined for ~13% of the American West. Much of the American West has also seen declines in maximum Snow water equivalent in many of the same areas where the snow season length has shortened. Incidentally, the areas that have seen some of the largest declines in snow season length and maximum SWE have been the same ones that have seen the worst wildfire outbreaks this year. The combination of reduced total snowpack, reduced max snowpack, and reduced snowpack season combine to leave trees more vulnerable when wildfires occur.
While declining snowpack is a big factor in Colorado’s wildfires, it’s certainly not the only factor. The image on the left illustrates the range of bark beetles across the Western US and Canada. Bark beetles drill through the outer layer of bark on trees and lay their eggs in the trees cambium, it’s growing layer. When the eggs hatch, the larvae eat the tree’s cambium from the inside out. When the snow season shortens the dry/warm season necessarily lengthens, increasing the amount of time bark beetles can infest America’s trees. Compounding matters, when trees have less water, they have less ability to fight off bug infestations with their natural defense mechanisms.
Climate change is worsening the Colorado wildfire season in a variety of other ways. One paper released earlier this year found that the ‘megadrought’ across the American Southwest (including Colorado) was the second worst in the last 1,500 years, with climate change accountable for 47% of drought severity. This climate change exacerbated drought increased temperature, decreased relative humidity, and pulled more moisture out of the ground, all things scientists have been saying climate change would do for decades. When drought is maintained for longer periods of time, it weakens forest ecosystems ability to survive fires.
In the week preceding Colorado’s fire outbreak, most of the state was in the worst category for short term drought per the NOAA. This is on top of the long-term drought plaguing much of the American West, with some of the most severe long-term drought in Colorado. Colorado’s record fire season has the signature of climate change all over it: severe long and short-term drought, the last twelve months far over the historical average, decades of snowpack decline and associated reduction of water availability, alongside growing infestations of bark beetles taking advantage climate-shortened Winters. The Cameron Peak Fire, still threatening Fort Collins, was turbocharged by our ongoing changes to the global climate, such that it has burned nearly 1000% more acres than any fire in Colorado history prior to the year 2,000.
And they say we got crazy and we tried to touch the sun
Unequivocally, burning fossil fuels releases the energy that was stored by decaying plants and bacteria millions of years ago. Our quest for cheap energy has literally resulted in burning ancient biomass stores of sunlight to create a cheap imitation of the sun’s present energy. Continued use of fossil fuels is saddening and infuriating given recent advances in renewable energy tech. Unfortunately, our society is still largely under the sway of fossil fuel interests. The ongoing burning of fossil fuels is unmistakably responsible for the fires underway in Colorado.
The shadow from the starlight is softer than a lullaby
Fort Collins has been under the veil of darkness for over two months now, as shadows dance under the smoke of the Cameron Peak and Mullen fires. On some nights the past few months, the starlight has been truly softer than a lullaby, barely peaking through the smoke of the wildfires. Of course, actual lullabies gift little comfort when the largest wildfire in Colorado history is burning just over the hillsides to your West. Many Coloradans in Fort Collins, Loveland, Longmont, and Boulder have spent nights this past week with the fear of fire and the smell of smoke on their minds as they drifted to sleep. Nobody wants to live in this climate changed world.
Satellites saw the silver clouds below
Another eerie development in the spate of fire outbreaks in the 21st Century is the advances in satellite imagery of the various wildfire outbreaks. While it’s scary enough to marvel at towering pyrocumulous clouds from below, seeing them from satellites gives some awe-inspiring sense of their sheer scale. It’s one thing to say that 200,000 acres burned in the Cameron Peak fire, and another to see the smoke from fires in Colorado stretching across the Great Plains all the way to Chicago.
Although record-breaking wildfire outbreaks across the American West are scary in their own right, the smoke itself may well be even more harmful to society. A recent paper by researchers at Stanford estimates that 1200 excess deaths were attributable to inhaling smoke from this season’s wildfires in California, with another 4800 hospitalized. While smoke doesn’t damage structures and uproot lives the way California’s infamous fire that burned down Paradise, that same Camp Fire was the deadliest in California’s history with 87 killed. This number is dwarfed by smoke related deaths from wildfires. Vulnerable population in Fort Collins bathed in wildfire smoke for the past two months are at higher risk of death as a consequence of the climate change fueled fires.
But our hearts still know some fear
Colorado is not in the clear yet. Although there is some colder weather in the short term, Colorado’s drought problem is likely to persist into next year. The Cameron Peak Fire is still burning just West of Fort Collins and Loveland, threatening both cities should the winds blow the wrong way. And two more fires have broken out in Colorado today, the Lefthand Canyon Fire West of Boulder and the (confusingly titled) Cameron Fire in El Dorado County. As meteorologist Guy Walton notes in his blog, drought is forecast to persist for the entire state of Colorado from now through the end of January.
The climate keeps changin’ fast and this iteration won’t last long
Unfortunately, the record-breaking fires around the world this year are not ‘the new normal’. Because carbon dioxide from fossil fuels stays in the atmosphere for hundreds to thousands of years, the CO2 we burn now adds to the total mass of greenhouse gases warming the planet. Every year, the fossil fuels we burn increase the total accumulation of carbon dioxide, further increasing the warming forcing from solar radiation. Consequently, so long as we continue to burn fossil fuels, the fire seasons will continue to get worse. As memorably bad as the 2020 fire season has been, with continued use of fossil fuels, the fire seasons will continue to get longer, larger, and more dangerous. It’s imperative we get off of fossil fuels as soon as possible to make sure that the fires of 2020 don’t get drastically worse. If we stop emitting fossil fuels, the temperatures will stabilize near their current levels.
Coming home to a place we’ve never seen before
Luckily, there are ways to get to net-zero carbon emissions in the near future. A transition to renewable energy can help provide the home we always wanted, whether we’re talking about the house we always dreamed of, or a habitable planet for all living things. A better world is possible, we are not doomed to ever dwindling climatic fortunes. This place we’ve never seen before, of climate and ecological sustainability, can be the home we never knew we always wanted. It’s time for Colorado and the rest of the world to come home.
