North America puts very little CO2 into the atmosphere. The reason is because of the huge forest areas in the United States and Canada. People are often surprised to learn that North America has more forest than any other continent. Environmentalists and "greens" are aware that North America adds little to the CO2 in the atmosphere despite the large amount of energy produced in the US, but they don't like to acknowledge it. The reason is that they want the US punished for its success; they want to reduce the US to the third world economy level. Obama agrees with that position; as his Aides have said, he views his mission as to manage the decline of America. Here is an article that mentions the CO2 situation from the blog Strata-Sphere. There is a lot more in the article about what is wrong with the AGW hypothesis.