So, the EPA and the current U.S. administration squares off against twelve states and enviornmental groups in front of the Supreme Court today. Rather than go over the particular legal issues involved, which are done better by lawyers, I’d like to meditate a bit on the very idea of Carbon Dioxide as a pollutant.

There’s an interesting surface plausibility to saying that carbon dioxide cannot possibly be a pollutant. One simple reason is that humans exhale it — so how the hell could that be a pollutant? One wants to say, however, that if we’re using the “naturally produced by humans” standard, urine and excrement also cannot be pollutants.

Like so many things, whether something pollutes is a matter of proportion. Quiet noise is just fine, but increase it too much and it becomes noise pollution. Same for urine — a little bit nature can handle, but if everyone pisses and shits outside without an organized system, well, you have pollution and a serious public health hazard.

This line of thought shouldn’t divert us from one of the serious ironies of the last twenty or thirty years, however. In the seventies, there was a worldwide worry about global cooling. It turns out that, even though at the time we were entering the middle stage of our drunken carbon bender, the world experienced global cooling because all the aerosols — read ‘godawful sulfuric and nitrogenous airborne gunk’ here — reflected so much radiation. As we and Europe tightened up our laws about airborne visible pollution, we left the pure waste product, carbon dioxide, out of our thoughts. Carbon dioxide is odorless, colorless, used by plants, and basically what would seem to be the ideal by-product of anything we might do.

I think about that pure by-product, carbon dioxide, now as a sort of extra-pure drug. We didn’t know it at the time — we thought, There’s no way “that” could be a drug, or damaging to us! Carbon dioxide seems so pure that we used to think this way: If we could just clean up all the gunk we could see, we could have our industrial cake and breathe it too.

(Similarly, oxygen seems to be another model of purity — but, again, too much oxygen and the room explodes, and burning oxygen in the body creates free radicals, which are primary causes of cancer.)

A pessimist might say that our problem is wanting the fruits of industrialization in the first place. But that’s a whole other topic.