It seems to me the biggest argument against doing something is that any action we take would be useless if country X doesn't do anything.
But with a carbon duty, this is much less of a difficult collective action problem. Impose a significant duty on products coming from countries which are not meeting some reasonable target for carbon emissions.
If France imposes a carbon duty but Britain doesn't, British companies will have access to cheaper goods. British citizens will have greater purchasing power and British companies will have an economic advantage.
France might say, "Britain doesn't do anything about climate change" as they're supporting the carbon emissions in other countries by importing their goods.
This would still only work if enough countries banded together to enforce it that it became too difficult to grow an international company without access to carbon duty countries.
That is overall a very weak standard of evidence, and taken by itself isn't worth much at all. But taken with other incidents in the past few years people might reach the conclusion that there is a great deal of double standards being used to measure certain politicians. This results in a comment said in passing that signals they feel that the current acceptance or lack thereof of tariffs is another case of that double standard.
Perhaps one could argue that such said in passing remarks are not acceptable for the level of discourse excepted by NH comments (though this risks becoming recursive).
If the country imposing the carbon duty isn't also meeting the "reasonable target" then the carbon duty becomes very hypocritical and ineffective at influencing other nations.
I also didn't say that it has to be the US imposing this carbon duty, I see it as most effective if it's a small group of countries working together to try and grow their action into a large group.
Energy Innovation and Carbon Dividend Act of 2019