Or in a more civil way, since it seems we have entered the era of tariffs wars, perhaps countries with carbon taxes should be slapping tariffs on imports from countries with none. Tie the tariff to some metric derived from a country's estimated CO2 emissions, subtracting some amount for % land mass in forests, reforestation efforts, carbon tax rates, deployment of renewables, etc.

It would have negative economic consequences in the short term, I'm sure. But put in place by large importers it would directly motivate emission offenders to not play the game of lowest-common-denominator.