Not only is what you described as 'tricky' - it's considerably too expensive and unworkable. We have a hard enough time agreeing on basic things, let alone get into the operational details of 'inspectors' from 'foreign countries' waltzing around.
We can't even do with money ie where it really matters. There are no real generally accepted accounting practices in large swaths of the world. And even then - things get tricky and ambiguous.
No - just tax the fuel and that's it. The fuel gets a harmonisation if it's taxed somewhere else and coming into the country and that's that.
Nope, we can do with money. Why do you think Swiss banks are so averse to open accounts for US persons? They don't want to be subject to US reporting rules. It gets harder with paper money
I agree fuel taxes are best. But the issue remains - how will you know that the manufacturer is buying taxed fuel (not black-market, untaxed oil, or untaxed oil that China is importing from Venezuela with a bilateral agreement)? Inspections.
It would be complicated, but the West (US + EU + the rest) are big and powerful enough to make it happen.
The US having digital access to financial records of citizens in Switerzland, is not comparable to the scale of government entities overseeing the entire global manufacturing base.
The US/EU could feasibly make some kind of trade pact, whereby producers are required to indicate the carbon used in each product, but there is no feasible way to oversee it.
COVID masks are literally being made by people in 're-education jail' in China. Safety and operational standards in many parts of the world are simply non-existent.
We can't even do with money ie where it really matters. There are no real generally accepted accounting practices in large swaths of the world. And even then - things get tricky and ambiguous.
No - just tax the fuel and that's it. The fuel gets a harmonisation if it's taxed somewhere else and coming into the country and that's that.