I agree that a subsidy is infeasible policy. But it wouldn't be effective even if it were feasible to pull off.
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's not clear that total carbon emissions decrease.
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's not clear whether carbon emissions decrease or increase.
Either way it'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 increase carbon emissions
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's not clear that total carbon emissions decrease.
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's not clear whether carbon emissions decrease or increase.
Either way it'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 increase carbon emissions