The Energy Information Adminstration; "Many gases exhibit these “greenhouse” properties. Some of them occur in nature (water vapor, carbon dioxide, methane, and nitrous oxide)"

The American Geophysical Union; "Infrared (IR) active gases, principally water vapor (H2O), carbon dioxide (CO2), and ozone (O3), naturally present in the Earth’s atmosphere"

Wikipedia; "Naturally occurring greenhouse gases include water vapor, carbon dioxide, methane, nitrous oxide, and ozone."

He, he, ok Koasati. Maybe I have to specify here.

Water-vapor is not considered to be a "greenhouse-gas" influenced by humans, as we don't produce water. Unlike CO2 it has a very short life cycle, taking only about a week before it comes back to Earth by rain/snow/hail.....short, it's in equilibrium.

And there is another very important difference between vapor and the other greenhouse-gases: vapor absorbs heat, CO2 doesn't.

The "water-vapor is the biggest greenhouse-gas"-phrase is sadly often used to imply that we humans couldn't possibly influence the composition of the atmosphere. But those people forget that water has the most unique properties of all the elements.

I read Gore's book and saw the movie. End result in my opinion...he is a snake oil salesman.   

Koasati,
I would pay heed to what aufisch has to say in this area, she has a PhD in Marine Biology and is about to "open upa can a salty whoop-ass on ya".   

May I suggest The Skeptical Environmentalist: Measuring the Real State of the World?

The science and statistics have been questioned but I have as much faith in this author's numbers as I do for the-sky-is-falling environmental crowd.

The wife and I talk about this a lot and think that we can always do more for the environment but that it will never be enough for some people.

I don't use screensavers, I just put my computer into sleep mode.