[xoa]

>What will you do with countries who refuse to comply?

What are you on about? They can't "refuse to comply" in the above scenario, because it's a matter of pricing in carbon on imports. They can either comply with a process to verify that all carbon inputs have already been neutralized, pay the cost to neutralize them, or else America/EU/Japan/whoever else participates will simply slap on a very conservative carbon price themselves. No cooperation is necessary, if they don't want to bother their products will simply be priced somewhat higher than if they had and thus they'll probably sell less.

>Is this really an existential crisis for our species?

Well, yeah, but at this point a lot could be done just by the first world fixing its markets to properly internalize carbon emissions and make all fossil fuels carbon neutral, which will then also help make a path for ramping up of negative emissions. China is certainly one of the biggest economies, but even they aren't in a position to just give up on all exports to the first world without more expense than just participating in a proper free market. It's in their interest too anyway.

[robjan]

They will then create workarounds, as they already do for tariffs. The most common one is to find an intermediary country and ship the goods through there.