Plant's release CO2 at night because they're not removing it through photosynthesis (since the sun is gone). So to stay alive they burn sugars that they created in the day using up O2 and producing CO2. However if you look at the total CO2 taken in, and the total released over the course of a day, more is taken in then put out.
High school chemistry is notorious for leading you to believe that if the numbers of two reduced molecular equations are the same that it all happens in the same proportion.
But you somehow forget that high-school chemistry only teaches very small portions of what isn't really a closed system. That's important.
The global warming bandwagon is so big that it'd be hard for there not to be some BS in there. However I'm more concerned about the fact that almost the entire anti-global warming movement is funded by the petrochemical industry.
In regards to your first piece of evidence, I'm not sure why a scientific paper from 1999, which has never been put in a peer reviewed journal, and by the most accurate estimates I can find has as of 2001 had already lost over 80% of it's key supporters can really be considered solid scientific evidence. Especially considering how much the science has changed since it came out.
@Graham
Ya, you're chemistry teacher showed you the equations for sugars a plant produces generally and more specifically one type sugar (and if we're getting really picky he just gave you a general formula that doesn't show the multitude of steps that are taken by plants to photosynthesize that type of sugar). What's really important to remember though is sugars are made by plants specifically to be consumed to power themselves, so of course they will be consumed and turned back into CO2.
However, there are a multitude of other carbon structures that plants make that are not consumed. Cellulose is the most common, but there are tons more that make up the bark, wood, stems, leaves, and other parts of plants. These lock in carbon for the life of the plant, and some of it ends up trapped in the ground after it dies. But regardless of that a stretch of forest represents a set amount of carbon that's currently trapped in those plants and as such not in the atmosphere. That's the primary reason plants are important.
Really? I was unaware of that. If you could explain?
It's kind of odd, there are about 40 major scientific bodies that have made statements saying humans are the cause of global warming, and 6 which have made statements that don't say what the cause is. The only major dissenting opinion came from the American Association of Petroleum Geologists, who are made up of people who rely on heavily carbon producing activities for their livelihoods, and they changed their statement in 2007. The only major scientific dissent against "Al Gore's consensus" was the petrochemical industry themselves, and they have since changed their opinion.