With all the talk about "global warming" recently, there seems to be one fact which is overlooked by many of the enviro-nazis in their rush to blame humanity for all the world's problems.
What is the primary cause of heat on the earth? The sun. Without the sun, there is no amount of human-created anything that is going to warm this planet for any significant amount of time.
This is NOT to say it is impossible for mankind to effect the amount of the sun's heat which is captured by the earth. However, before drawing that kind of conclusion, you must first determine that the sun is burning at the same intensity or less than in previous years. Increased solar activity could lead to increased global warming. Until that possibility is excluded, all other theories are in doubt.
To only look for human causes of global warming is an anthropocentric assumption.