Contrarily you could take the Bill Gates route which is focus on rapid Carbon Sequestration and Nuclear Power. The budget for these sectors should be at minimum around 2 trillion each year (500 billion for R&D and 1.5 trillion for infrastructure development). What I don't understand is the reluctance to throw all of your chips onto the table in a dire situation. In a system like Capitalism this will never happen due to the inherent risk in the for-profit financial model.
We should be scaling down our overhead across the board. Our housing should be efficient and affordable. We should be reducing transportation, grounding all non-essential aviation, etc.
The enemy is the for-profit model, i.e. capitalism. Something like the above could be accomplished in a technocratic civilization. (by necessity demanding the cessation of democracy)