So given that there's a snowball's chance in hell that world governments will act on this, what are the likely scenarios we will see regarding resource scarcity and social breakdown. What can we as individuals do to protect ourselves, at various time scales of 10, 15, 20 years, etc.?

Expect homeowner's insurance in coastal areas to rise, real estate prices to fall, and sales of AC to increase.

A few ideas responsive to your question:

https://news.ycombinator.com/item?id=18168203