re: #297 eon

And, in a neat bit of legerdemain, they’ve also defined water vapor as a “greenhouse gas”.

Technically, they’re correct. Water vapor is a greenhouse gas. It actually supplies the largest fraction of the greenhouse effect that keeps our planet warm.

The difference, however, is that by combusting fossil fuels, we are releasing carbon dioxide that has been sequestered in mineral deposits for millions of years. This is not true of our use of water, which comes from the water cycle and does not have an effect on the net amount of water vapor in the atmosphere.