'We' can absolutely influence global warming caused by developing nations' emissions. Look at the trajectory of industrial pollution per capita in the developed world - it started low, but as industrialization catalyzed by fossil fuels took off, it crept up exponentially. When this was happening, the developing world was not even on the development trajectory, as most of it was reeling from colonialism or other ills.

Shift to now, the developed world has offset quite a significant bit of the per-capita emissions by purchasing carbon credits from the developing world in the name of helping them grow, or simply shifting expensive manufacturing to these countries where it gets counted as their emissions and their problem.

So, what do we do? First, simplify the accounting so that there is a very clear and direct overview. Today, you have billionaires flying around in jets, but still not showing up as large scale emitters since they can afford enough credits to look at it as a minor inconveniencing tax.

Secondly, we need to make green energy affordable (just the way the fossils were dirt cheap for the developed world) for these countries by using economies of scale - deploy green energy generation in the developed world which would make it cheaper. Where does better accounting come in? When your manufacturing based emissions count as yours and not the developing world's you will have an incentive to pay more to also offset the emissions, instead of just shifting physical manufacturing.

I do agree that small scale individual sacrifices are mostly useless, as there's just little efficiency in doing smaller things than making huge changes on a more scalable level. You could give up flying for an entire year, but if you only fly 10 times a year, that's still less than a billionaire not flying private just once.

We need more accountability. We have the technology, the solutions, but we lack in accountability.