Greenhouse Gasses and Global Warming

In answer to a taunt about water vapor being the main greenhouse gas.


Contribution of water vapor to the greenhouse effect is well known. That doesn't mean the other greenhouse gasses have no effect.

Without any GHGs, the Earth's average surface temperature would be -18 C, or -0.4 F. Thanks mostly to water vapor, average surface temperature is more like 15 C, or 59 F. That's a difference of 33 degrees C, or 60 F.

Raising CO2 levels by 35% has raised that by about 0.6 C, or 1 F. Lucky for us isn't a huge effect!

Doubling CO2 will raise Earth's average surface temperature by another 3 C or so, 5 F. Still not huge, but it's enough to change things significantly.

But then suppose we're also in a natural warming cycle that will heat us up by another 3 C for a total of 6C, 11F. That's a huge change, enough to have truly drastic effects.

This is the gamble we're taking, the big experiment we're conducting on our home planet from which there is essentially no escape. And it's a gamble that can't be taken back for at least a century. If nothing else we need to be prepared for the consequences.