Comment Lie down on the floor and keep calm (Score 1) 468
Okay, first of all, you can forget about the CO2 in the pressurization: that was collected from the atmosphere, and goes back, net carbon is zero. Similarly, since beer is made from plants, pretty well all the CO2 produced by making beer is absorbed again making next year's beer.
Just for fun, though, let's do a back-of-envelope calculation of how much there is. According to Wikipedia, humans brew about 133 gigaliters of beer a year, and we can assume it's about 5 percent alcohol, so that's (133×0.05)=6.7 gigaliters of alcohol. The specific gravity of ethanol is about 0.8 so that's 5.3 billion kilograms of ethanol per year. One mol Ethanol (CH3CH22OH) masses 45 grammmes. So that's 5600 billion grams of alcohol, 120 billion mols, and it turns out that there's 1 mol of CO2 per mol ethanol.
Thus we get 120 billion mol of CO2, a mol is 44 grammes, about 5.3 million tonnes. According to WikiAnswers, a car produces about 5.2 tonnes of CO2 per year, so all the world's beer production is about equivalent to a million cars.
So if it worries you, buy a couple CFL bulbs or soemthing. It's pretty small.
(PS. This would look better if