Ah sure. I wasn't making the point not to have a carbon tax. Just that it would help here unless carefully thought out. A bit like the biodiesel law.

Not at all. That creates an effective subsidy on non-domestic production. Carbon tax on my factory in California? I’ll move it to Nairobi. Add a tariff? Then other countries retaliate and domestic companies can no longer sell their goods abroad. Domestic consumers would pay higher prices and the economy grinds to a halt due to reduced production from reduced international trade.

Why wouldn't companies start producing less carbon intensive products? Seems to have worked pretty well with cars, which even with the recent dieselgate, are much more efficient than before.

Currently there's an effective subsidy on air polluters; I can sue my neighbor who dumps waste on my land, but I can't sue the people dumping carbon in my lungs. Is that subsidy not concerning?

Are there measures to combat global warming that you do support?