Warm take: Our main hope lies in the EA/longtermist/AI-safety community. I say this because my first-order answer to your question is “no idea,” so instead I go meta and say “Rally the community. Get organized. Create common knowledge. Get the wisest people in a room together to discuss the problem and make a plan. Everybody stick to the plan.” (The plan will of course be a living document that updates over time in response to new info. The point is that for a crisis, you need organization; you need a chain of command. It seems to be the main way that humans are able to get large numbers of people working effectively together on short notice. The main problem with organizations is that they tend to become corrupt and decay over time, hence the importance of competition/markets/independence. However this is less of a problem on short timescales and anyway what choice do we have?)
Warm take: Our main hope lies in the EA/longtermist/AI-safety community. I say this because my first-order answer to your question is “no idea,” so instead I go meta and say “Rally the community. Get organized. Create common knowledge. Get the wisest people in a room together to discuss the problem and make a plan. Everybody stick to the plan.” (The plan will of course be a living document that updates over time in response to new info. The point is that for a crisis, you need organization; you need a chain of command. It seems to be the main way that humans are able to get large numbers of people working effectively together on short notice. The main problem with organizations is that they tend to become corrupt and decay over time, hence the importance of competition/markets/independence. However this is less of a problem on short timescales and anyway what choice do we have?)