Climate changes and the local environment:
Over the past century, average annual temperatures have soared across Montana, rising by almost 2° C (3° F) relative to twentieth-century averages. Warming has shortened winters, and earlier thawing has prevented snow from accumulating. Hotter spring, summer, and fall temperatures have also increased the rate of evaporation across Montana.
Average annual precipitation in Montana has increased modestly. However, rainfall has only increased in the early spring and late fall, and precipitation in the summer has actually become more scarce. The summer dry season is therefore drier and longer than it once was. Extreme droughts are now much more likely to occur than they once were.
Together, these changes have created ideal conditions for wildfires in heavily forested but sparsely populated Garfield County, Montana. In the summer of 2017, no fewer than 21 wildfires broke out in Montana during a particularly severe, long-lasting drought. Together, the wildfires consumed nearly 1.3 million acres of forest, and two fires alone each burned across over 100,000 acres.
National data suggests that climate change, not shifting forest management practices, were responsible for the 2017 wildfires in Garfield county. Beginning in the 1980s, large wildfires across the United States suddenly grew more common, and lasted longer, especially in regions lightly touched by forest management practices. Almost everywhere, rising spring and summer temperatures, and an earlier spring snowmelt, were largely to blame.
By burning through old trees and brush, wildfires can bring new life to a forest, making way for diverse plant species and creating new habitats for animals. Yet the dramatic increase in the frequency, scale, and length of wildfires in Montana has interfered with the ability of forests to recover.
How we know:
These reconstructions are largely based on reliable, easy to use tools that are freely accessible online: the National Oceanic and Atmospheric Administration (NOAA) State Annual and Seasonal Time Series, the NOAA Climate at a Glance app, the National Drought Mitigation Center's United States Drought Monitor.
NOAA's State Annual and Seasonal Time Series and Climate at a Glance tools use data collected at weather stations and stored in NOAA's U.S. Climate Divisions database. The Drought Monitor compiles weekly maps of drought conditions across the United States, and combines climate, soil, and water data with reports from 350 experts across the country.
These reconstructions also draw on visualizations provided by the National Interagency Fire Center, which has created a tool that predicts the potential of new wildfires based on previous weather conditions. They also rely on an important 2006 study in the journal Science, which finds clear links between warming and wildfires.
In recent decades, the environment of Garfield County has grown more dangerous for its human residents. In 2017, the Lodgepole wildfire spread into Garfield County and eventually consumed an area the size of New York City. After billions of dollars were spent to control the fire, and two firefighters lost their lives, the county nevertheless lost over 20 buildings.
Meanwhile, drought and wildfires have together undermined cattle ranching, a staple of Montana's economy and culture. Fires not only destroyed grazing land and killed cattle, but also incinerated nearly 2,300 km (1,300 miles) of fencing, and required costly hay imports. Some ranchers have had to sell cattle in huge quantities because there is no more grazing land to support them, and many ranchers will lose "genetics" that have taken years to hone. Young ranchers have seen their businesses ruined before they ever got off the ground.
The destructiveness of the 2017 wildfires have provoked renewed debate about logging in the forests of Montana. Advocates insist that logging reduces the risk of forest fires and spurs Montana's economy. Skeptics point out that although millions of acres of forest have been cleared of dangerous fire "fuels" - including in Garfield County - wildfires nevertheless burned uncontrollably. Droughts worsened by climate change have overwhelmed local attempts to confront wild fires.
Long-term Losses of Montana's Fire Season Amount to Much More than Scorched Grass. Billings Gazette
Montana Wildfires Reignite Logging Debate. NPR
Wildfire Myths: Logging the Forest Won’t Save It. Counter Punch
Garfield County Community Wildfire Protection Plan. Walsh Environmental Scientists and Engineers, LLC
Article author: Sabine Neschke, Georgetown University
Article editor: Dr. Dagomar Degroot, Georgetown University