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).

There's plenty of demand for such housing. Keep building it until environmentally-friendly housing is cheaper than other housing.

Heating & cooling are a big deal. IIRC, average personal energy use is lower in LA metro than NYC metro, b/c climate control > transport.