Photo by USAF.

The wildfires raging through Colorado and the West are unbelievable. As of yesterday there were 242 fires burning, according to the National Interagency Fire Center. Almost 350 homes have been destroyed in Colorado Springs, where 36,000 people have been evacuated from their homes. President Obama is visiting today to assess the devastation for himself.

Obviously the priority is containing the fires and protecting people. But inevitably the question is going to come up: Did climate change “cause” the fires? Regular readers know that this question drives me a little nuts. Pardon the long post, but I want to try to tackle this causation question once and for all.

What caused the Colorado Springs fire? Well, it was probably a careless toss of a cigarette butt, or someone burning leaves in their backyard, or a campfire that wasn’t properly doused. [UPDATE: Turns out it was lightning.] That spark, wherever it came from, is what triggered the cascading series of events we call “a fire.” It was what philosophers call the proximate cause, the most immediate, the closest.

All the other factors being discussed — the intense drought covering the state, the dead trees left behind by bark beetles, the high winds — are distal causes. Distal causes are less tightly connected to their effects. The dead trees didn’t make any particular fire inevitable; there can be no fire without a spark. What they did is make it more likely that a fire would occur. Distal causes are like that: probabilistic. Nonetheless, our intuitions tell us that distal causes are in many ways more satisfactory explanations. They tell us something about the meaning of events, not just the mechanisms, which is why they’re also called “ultimate” causes. It’s meaning we usually want.