But not everyone agrees on its causes, and even fewer agree on its cure.
The prudent course is to roll back CO2 emissions, while allowing the scientific process to continue working out the answers. The ultimate causes that are identified may surprise some, but we can't afford not to take our best shot right now.
We must also work to ensure that the emissions rules apply to all nations. We are all breathing the same air.
Meanwhile, I hope that more and more people begin to understand that climate (like traffic, human emotions, and stock prices) are examples of nonlinear, or "chaotic" systems, and that common-sense rules of cause and effect do not apply. The end state of such systems cannot be predicted from their initial conditions (in pop science, this is called the "butterfly effect").
The following book is as good as any I know of for an introduction to such systems, which abound in Nature. It's also beautifully written. Read it, and you will not see the world the same way again. You can buy it used for 75 cents. A small price for fundamental understanding.
Chaos: Making a New Science, by James Gleick
http://www.amazon.com/Chaos-Making-Science-James-Gleick/dp/0140092501/sr=8-1/qid=1169534052/ref=pd_bbs_sr_1/002-2720660-8775239?ie=UTF8&s=booksPeace.