Barring specific chemicals in cigs but not in fuel naturally. Sadly, a quick net search will find a wikianswer claiming cigarrettes produce 34% of CO2 emmisions, which is so brutally absurd I lack the words. Even with the massive number of cigs, 5 trillion, smoked annually, that doesn't even match up to the carbon monoxide or dioxide produced through any number of artificial or natural processes on a daily basis. The 5-10 grams of co2, and less of CO, produced are in fact carbon neutral, having been grown typically that year anyway. But the whole some of cig CO2, based on that, per annum, should be 25-50 trillion grams, 25-50 billion kilograms, 25-50 million tons, or 25-50 megatons, or a small fraction of a percent of other emmissions, and again, basically carbon neutral.