As soon as the incentives dictate it and no sooner

Rome wasn't built in a day.

Anyone who sees us getting to minimal emissions much faster than our current trajectory is pretty naive.

We're already on a trajectory where it's reasonable to believe we could have minimal emissions in the US, the EU, and China by 2060.

If you see this happening by 2030 or even 2040 - you're dreaming.

When it starts seriously affecting the oligarchs.

Probably not a second before food and freshwater shortages have an effect on the wealthy.

This is a world-wide tragedy of the commons. I think a world dictator would be necessary. But perhaps if the largest economies imposed a carbon tax - including on traded goods, then mitigation could be accomplished.

When radical life extension becomes a thing.

before or after live warfare over the oil supplies?

When it becomes an actual problem.