"Cost of a trillion dollars? What trillion dollars?" That would suggest the cost is around the same as the second gulf war then. Considering what has been gained from that little war (nothing) investing the same sort of money in GW mitigation would seem a far better investment Chief "Didn't you learn in grade school that you exhale CO2?" Strangely we did, but we also learned that the exhaled Co2 came from what we ate so that would be a cycle, you take in Co2 from food, which in turn took it from the atmosphere, you breath it out and the cycle continues. Fuel and coal on the other hand has been underground for 10s of millions of years so those outputs are adding directly without a balanced offset. Cows are a problem because they produce large amounts of methane which is a much stronger greenhouse gas than Co2, diet is the main cause of this mostly a grain feed diet, native animals usually feeding on grass produce considerably less methane.