I've written about all this including in a book. Your numbers are good, especially the remaining reserves, etc. I am not Polly Anna but I would like to suggest that things never go all the way to terrible. First capitalism, for all of its flaws, and there are many, has a vested interest in providing solutions. I'd say that no capitalist wants to deploy solutions until it is clear they can't make enough profit from the fossil fuel paradigm.

That said, you overlook other energy sources such as geothermal. There is enough heat energy under the Rocky Mountains to supply our energy needs 3x according to studies I have seen from places like MIT.

Believe it or not I do not think energy per se is our biggest concern. There are two or three that trump energy.

First, net-emissions is the phrase we should have tattooed on our eyelids. Simply put we have the ability to capture and sequester carbon from the environment but we are not doing anything about it. Long term, capture and sequestration are our ace in the hole.

Second, population needs to come down and it is on its own. The Eurasian continent is losing headcount. The numbers are small but we're just getting going. Ditto for North America.

Third, food production and by extension fresh water production are critical to keeping the world fed and to removing carbon for technical reasons.

With a net-emissions awareness and reliance on geothermal, we can have any scenario we want to dream up.