To support the Paris agreement: advocate, locally, for housing dense enough to support transit good enough for the rich to not want cars.

Even better: do this primarily in areas with low heating and cooling costs (such as coastal California).

but then you have to include the cost of rebuilding everything after California falls into the ocean.

California falling into the ocean is way way after London, Paris, New York, Tokyo, Beijing, Kolkata & Mumbai are destroyed by sea level rise

The Big One could strike tomorrow. Sea level rises won't.