I am part of the political left. Not sure what kind of argument you are making, carbon emissions plummeting is good no matter what. If we can do it for cheap, even better.
In fact, mitigating climate change due to technological innovation and the free market is preferable than achieving it due to regulation and massive public spending programs. Why? Because unless you are able to enforce regulations on every country on Earth, what would happen is that energy-intensive industries would just shift to countries with lax regulations. It is not stable, in a game-theoretic sense, for every sovereign entity to have strict renewable energy standards, as any entity violating those standards has an immense competitive advantage over other entities.
The only thing I am dissatisfied about is the pace, because we are not transitioning fast enough to avoid some of the long-term effects of global climate change.
> if the oil revenue drops to, say, 50% of current levels, I think that there will be problems sooner rather than later.
They have a sovereign wealth fund to protect against this. Look to Qatar and the UAE to see where they want to go in the future.