The Copenhagen treaty would do nothing to stop global warming, even if you believe in it.  Here it is, right from Time magazine.

"A paper leaked from, and confirmed to be authentic by, the U.N. on Thursday night contains an assessment of the emissions-reduction pledges put forward so far in Copenhagen. It calculates that even if all developed and developing nations keep their promises, atmospheric carbon concentrations would rise as high as 770 parts per million, and temperatures could rise 3°C by the end of the century. The upper safe zone in temperature rise, according to many scientists, is 2°C, and the limit called for by vulnerable island nations is 1.5°C."