You would think that Global Warming would actually be happening Globally, wouldn't you?
CO2 levels have increased the same amount everywhere in the World (Source
http://cdiac.esd.ornl.gov/trends/co2/contents.htm). The same increases have been recorded at the South Pole, Seychelles and Mauna Loa for instance.
New York, NY 1822-2000 recorded a rise of 5 degrees Fahrenheit in a hundred and seventy-eight years (Source United Stats Historical Climatology Network)
Albany, NY 1820-2000 has recorded a decline of half a degree in a hundred eighty years (Source United States Historical CLimatology Network).
Conclusion: While CO2 levels have raised uniformly, two cities merely a hudred and forty miles apart have experienced different heating/cooling effects. One has gotten hotter while another has gotten colder. How does this fit your theory of green house gasses?