There have been quite a number of high-profile wildfires in the western US in recent years — to the point that even many of those involved in the fighting of these wildfires have been surprised at the destruction wrought by them.
To be more exact, the acres of forest that are burned yearly in the western US has increased 9-fold in recent years (1984–2015). According to new research published in the Proceedings of the National Academy of Sciences, the answer for this rapid surge in wildfires is simple — rising temperatures are to blame.
The research basically reveals that “more than a century of fossil fuel burning, deforestation, and farming has helped push the American West into an explosive new wildfire regime.” Things will only be getting worse from here on out, as extended and intense drought in the region becomes increasingly common.
“The authors clearly demonstrate that a human influence on wildland fire as a consequence of global warming isn’t just a prediction for the future — it’s happening now,” stated Kevin Anchukaitis, a University of Arizona scientist who was not involved with the study.
“The exact percentage of human contribution remains uncertain, but the overall relationship — an increase in fuel aridity, fire days, and fire extent — is clear and significant,” Anchukaitis continued. “The statistical analysis is very convincing and elegantly done.”
Climate Central provides more: “The new analysis showed temperature increases caused by rising levels of greenhouse gas pollution have had a drying effect on Western forests that caused 10.4 million acres to char in large fires during the three decades. That suggests 44% of the forest area that burned during the three decades analyzed burned because of the effects of global warming. The finding was an estimate, with the researchers concluding global warming likely drove between 6 million acres and 16 million acres of forest fire.”
In addition to increased aridity, fire seasons have increased in length as well, as a result of rising temperatures.
According to a co-author of the new paper, John Abatzoglou, a geographer at the University of Idaho, climate change and natural weather fluctuations have compounded to give “rise to this remarkable increase in forest fire activity.”
Continuing: “The study focused on the heavy role that temperatures can play on forest fires, ignoring other kinds of wildfires, such as those afflicting grasslands, and ignoring other factors that can shape fire seasons. Fires need ignition sources to get started — these include lightning strikes, arsonists and campfires. They’re also affected by the thickness and type of vegetation that they consume, which in turn are shaped by weather, climate and wildfires.”
“The effect of warming on fire activity is actually exponential,” commented Park Williams, a researcher at Columbia University who co-authored the new study with Abatzoglou. “That means that every degree of warming has a bigger impact than the previous degree of warming.”
“Even though climate is changing gradually, the way that fire responds is not gradual,” Williams continued. “As warming continues, there will probably be another leap, where fires are getting quite a bit more energetic — and quite a bit larger.”
That means that current population levels in the region are likely going to change, one way or another, over the coming decades.