The only way it's gonna work is if a bunch of countries get together, agree a carbon cap/tax, and then tell other countries that they need to join the scheme if they want to trade goods with the group.
One way to combat corruption is to ask an international panel of experts to assess how many extra emissions came from non-official sources in each country and reduce next years cap by that amount. Then countries have an incentive to stamp out corruption.
I don't know. Corruption gets easier with increased centralization. I think a far better approach is to innovate our way out of it. If carbon free energy sources are less expensive then the problem will solve itself essentially. A global carbon tax will enviably extract some portion of global GDP from corruption. That money would likely be better spent in other ways.
Basically, carbon tax is the accountant's solution, innovation is the engineer's.
carbon-free will take a really long time to be cheaper.
As soon as demand for oil starts to drop, so will oil prices, and I suspect they could go down by a factor of 10 or more and oil-rich nations would still think it worthwhile to exploit at least some reserves.
One way to combat corruption is to ask an international panel of experts to assess how many extra emissions came from non-official sources in each country and reduce next years cap by that amount. Then countries have an incentive to stamp out corruption.