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Colorado Forest Fires and the Climate Connection

This post is part of WRI's "Extreme Weather Watch" series, which explores the link between climate change and extreme events. Read our other posts in this series.

While many Americans set up camp to watch fireworks on July 4th, those in the Western U.S. were not as lucky. Firefighters didn’t get a holiday reprieve as they battled ongoing forest fires in Colorado. Plus, at least 40 cities in the state as well as many in neighboring states cancelled their fireworks shows due to the high risk of sparking new fires.

Disappointed fireworks fans were the least of the region’s worries, though. Colorado is experiencing its worst wildfire season in a decade, with half a dozen lives lost, more than 600 homes consumed, and more than 270 square miles (more than 10 times the size of Manhattan) burned so far. And the state isn’t alone: Wildfires have already struck across 137 square miles of Wyoming and 380 square miles of Montana as well.

Several news accounts have blamed the Colorado fires on lightning. While that may have been the trigger, much research suggests that this summer’s widespread destruction is not an anomaly, but rather part of an ominous, ongoing trend.

What’s Causing These Conditions?

As we reported in a previous review of climate science, researchers have shown that fire activity in the West has increased in recent years, both in terms of frequency and length of burning season. The researchers also found that this spike has little to do with changes in land management. Instead, they pointed to a number of climatic factors, including spring and summer warming and earlier spring snow melt, which leave trees more combustible for longer periods of time.

Indeed, extreme weather patterns are creating a perfect storm for out-of-control burning. As the U.S. Drought Monitor shows, most of Colorado and surrounding states are currently blanketed in exceptionally severe drought. And current temperatures are unusually hot, according to NASA maps (which depict temperatures from June 17-24th, compared with temperatures for the same week averaged over the last decade. Warmer-than-average temperatures for the period are shown in red).

<p>NASA Earth Observatory image by Jesse Allen, using MODIS data provided by Land Processes Distributed Active Archive Center (LPDAAC).</p>

NASA Earth Observatory image by Jesse Allen, using MODIS data provided by Land Processes Distributed Active Archive Center (LPDAAC).

On top of these conditions, mountain pine beetle blight has already killed 3.3 million acres of Coloradan forests. These beetles dig themselves under tree bark to lay their larvae, but typically die in cold winters. The bugs are now persisting through winters that have become increasingly mild due to climate change and are infecting pines with a deadly fungus. The resulting dead trees are the perfect fuel for forest fires. In Colorado’s Fort Collins wildfire, for example, 70 percent of the burn area had been killed off by mountain pine beetles.

Fires: An Increasingly Frequent and Widespread Occurrence?

While the role lightning played in causing the Colorado fires shouldn’t be underestimated, we need to keep in mind the factors that allowed the fires to spread so fast and so far: heat and drought.

The bad news is that these conditions are projected to worsen as a result of human-induced global warming. According to the U.S. Global Change Research Program, a changing climate will not only bring warmer days and increases in fire range to the Southwest, but will create significant changes to the water cycle in a region that’s already witnessing a rapidly diminishing water supply.

Controlling the Problem

Yet is doesn’t have to be that way. Reducing greenhouse gas emissions could help keep our weather from becoming increasingly forest-fire-friendly.

The American public gets it: In a recent poll, 78 percent of respondents acknowledged that global warming will be a serious problem if left unchecked, and only a very small minority said government or business was doing enough to control the problem. We need America’s leaders in business, government, and other sectors to take a cue from the public – and our burning landscape – and take urgent, cooperative action to address global warming. Without such movement, devastating forest fires like those in Colorado may become a regular fixture in the American landscape.

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