I think right now, the vast majority of oil use is not because of corrupt officials using oil energy despite the fact that cheaper energy sources are available. Maybe that problem will eventually be a sticking point in removing all carbon-emitting energy sources, but right now the barrier is mostly production capacity and the scale of capital investment required to roll out renewables at scale. But if (as seems to be the case now) rolling out renewables is more profitable than rolling out additional fossil fuel use, the capital should become increasingly available. That's why I'm optimistic, even though of course there are a lot of challenges ahead in terms of creating a truly sustainable future.