It is a humorous story, but even so it is not good to spread misconceptions. Global warming is due to carbon dioxide produced by cars, not the heat of the combustion itself. And the combustion takes place in the cylinders, not the carburetor. Finally, opening refrigerator doors would produce even more heat, since the heat removed from inside the refrigerator is exhausted out the back (plus more to account for inefficiency). James Watt was a smart guy - he would see all these errors.