Note that if we impose a carbon tax we just drive a lot of energy-intensive industry offshore. China and India very much do matter. I think we might be able to handle this by applying the tax to imports. As a rough model, look at the value of the import as a % of their GDP, it's taxed that % of their total carbon emission, credit for any foreign carbon tax already paid.
Absolutely. There will need to be treaties and a method to account for the carbon cost even when something is produced abroad if we are to achieve aggregate reductions.
Unfortunately things look grim when you look at the state of international relations. It doesn't feel like we'll see progress on international carbon pricing anytime soon.
Nothing of this sort will be done because it would effectively block the access of those privileged enough to care about carbon taxes to the markets of those that cant really afford it.
Carbon taxes are irrational and not a viable alternative.
It's hard to keep an optimistic and creative imagination when the status quo is as bad as it is, but don't let the present malaise limit your horizons. There is more than one way out.
Total tonnage is all that matters when it comes to how much warming we will get. But when it comes to deciding how to limit the total to under that amount we have to come up with a limit for each country.
Why by country? Because that is how we've split the world up for regulating.
When deciding each country's share of that allowed global tonnage, per capita does matter. Other allocations, such as equal amounts per country, lead to absurd outcomes. Here's a comment giving an example [1].
why would being born with the right passport allows you to pollute 5x more with impunity? the planet doesn't give a crap about our made up borders. What makes Europeans/Americans individuals so special that they get to consume wayyyyyy more than the rest of the planet?
If anything, Europe and the USA and Russia should get way less carbon credits per capita, since they've had a massive headstart at consuming fossil fuels compared to the rest of the world, which should really be priced in somehow if we're talking about fairness.
The carbon footprint of the major economies is shrinking, and given the technological development since the dawn of the industrial revolution, there is no reason for emerging economies to have the same emissions profile as they ramp up.
Their carbon footprint is shrinking, but it's still higher per capita then most other countries in the world except China (or, for the USA and Germany, including China).
And, while progress has been made, fossil fuels are still by far the cheapest source of energy around, especially if you don't have great expertise. So, in principle, we should be letting the developing nations of the world use much more fossil fuels to power their economies, while those that have been using it for centuries at this point should use far less.
Note that I'm not actually advocating for this, as stopping global warming is far more important than some abstract notion of historical fairness in international politics, which is even more idealistic than world peace.
In India's case it's silly to make a comparison.