I agree that a subsidy is infeasible policy.  But it wouldn&#x27;t be effective even if it were feasible to pull off.<p>Suppose the government gives out free Priuses. Well, then people are going to drive more. Even though some people may be driving more fuel efficient cars, it&#x27;s not clear that total carbon emissions decrease.<p>Suppose the government provides free solar cells for everyone. Then people will use a lot more electricity.  But solar cells require some carbon emissions to produce, and since people use so much more electricity overall, it&#x27;s not clear whether carbon emissions decrease or increase.<p>Either way it&#x27;s just a totally goofy thought experiment, since a carbon tax is exactly the right answer, and this subsidy idea is so misguided that it could possibly even <i>increase</i> carbon emissions