Although I have studied sciences since I was young, I never quite understood why it is that trees are supposed to be good for the environment. As far as I know, they absorb CO2 during the day and release Oxygen, and do the opposite at night. If that is true, wouldn't these two processes cancel each other out? And, wouldn't the amount of O2 and CO2 vary depending on how many hours of day light there are? (i.e. there would be lots of O2 released in the summer- because of more daylight hours-, and more CO2 released in the winter- because of more night hours).It is quite well known that plants take in CO2 and metabolize it and "breathe out" oxygen (O2.) Now it is true that plants will respire at night (put out CO2) but they put out far more oxygen than carbon dioxide. They also "scrub" the air by taking in extra carbon and use that as food/fuel thereby removing emissions from cars and industry and volcanoes.
A much bigger concern in regards to global warming isnt what man is doing, it is what our sun is doing. Other planets are heating up (Mars) but we ignore that in favor of blaming America for all the worlds ills