It's worth noting that there's no international mechanism where countries can be "given a quota" unless they voluntarily agree to the quota, and there is no mec

It's worth noting that there's no international mechanism where countries can be "given a quota" unless they voluntarily agree to the quota, and there is no mechanism for enforcing compliance to that quota unless countries voluntarily choose to accept some consequences. It's not realistic to expect that such a tax would be paid across borders - by default, every country would pay net zero tax even if they are not net zero on carbon emissions; IIRC all the major emitters have explicitly refused to have climate solutions that involve significant wealth transfers from them to other countries, and there's nothing (IMHO even including extreme violence like WW3) that is likely to force them to do so. It is somewhat realistic (though difficult) to have most countries agree that they will tax polluters under a comparable rules & rates. It's not realistic to expect that they will use that tax revenue on someone else's citizens instead of their own. Also, 5% of gross product is a LOT. For a comparison, that is more than the global spending on education. I have a hard time believing that countries will choose to spend on carbon capture more than what they currently (or ever) invested in developing their citizens' skills.