Cathryn, The pollution you are talking about is not the same thing as CO2....that stuff is as likely to cause cooling as warming. CO2 is emmitted just as much with a catalytic converter as with no pollution controls...it is simple how much gas you burn (or, natural gas, or coal, or heating oil). The different types of fuel have a different amount of CO2 per energy unit. And...the problem is that places like Asia (which I have never visited, but could see when coming in to land at the Istanbul airport) is that why should they slow their economies to cut down on fossil fuel emissions when the US emits by far the most per-capita (and, I think 25% of the worlds CO2, but someone check this). Chris