Further to my puzzlement over the repeated comparison of carbon offsets to papal indulgences, Gar Lipow of Grist Mill clarifies that the comparison only applies when the offsets are so poorly regulated that they’re really no good. It’s a bit technical, but the basic argument is that any offset you buy to satisfy a legal obligation — like a government-mandated emissions cap — had better be rock-solid, not some airy-fairy promise to plant a tree somewhere nobody will ever check.
Otherwise, Lipow’s argument goes, it really is just a permit to pollute: the result is more emissions than there would otherwise have been, and that’s as bad as someone making a plan that includes both a sinful act and a few coins sent the Pope’s way. It’s not what you’d call virtue.
That makes sense as far as it goes, but again, there’s a difference between sinning and emitting greenhouse gases. Sin, in any respectable religion, is only forgiven following authentic repentance, whereas if you really can compensate fully for emitting some carbon, there’s no foul. As long as you get the gases out of the air, how you feel about it and whether you’re planning to do it again have nothing to do with anything.