Don't wildfires like the ones that recently devastated several hundred thousand acres of Oregon forest make a hash of our pinprick individual efforts to control greenhouse gas emissions? —Brian C.

Let's put it this way: In the long run, wildfires should be carbon-neutral, so you should have nothing to worry about. Of course, as John Maynard Keynes so memorably observed, in the long run, we're all dead.

U.S. wildfires release 290 million tons of CO2 every year, about 4 to 6 percent of our nation's total.

It's worth noting wildfires have been around pretty much forever, putting out millions of tons of carbon every year—but somehow, the earth has not been reduced to a molten hellscape. Could wildfire CO2 be somehow less dangerous?

Unlike fossil-fuel carbon, the carbon from wildfires has been part of our environment throughout human history. It came out of the air as the trees grew, it went back into the air when those trees burned, and when the forest grows back, it will suck all that carbon back out of the air again, in a groovy, never-ending exchange we call the "carbon cycle."

Fossil-fuel carbon, by contrast, was dead and buried for tens of millions of years—literally every organism on the planet evolved based on the presumption we would never see it again. When it enters the atmosphere, the carbon balance changes permanently.

But before you send a valentine to the Eagle Creek Fire, you should be aware that the groovy carbon cycle breaks down if, instead of allowing that forest to regrow, somebody turns the land into a strip mall.

There's also something of a vicious circle in that climate change exacerbates wildfires—if a larger portion of the earth is burning at any given time, more carbon will be loosed into the atmosphere.

But for now, fossil fuels are still the bigger enemy. Don't sweat the wildfires, keep driving that Prius, and if possible, evolve faster.

Good luck.

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