Solutions like these seem like they very well may do a good job in slowing global warming with relatively little effort/cost invested, but for political reasons

Solutions like these seem like they very well may do a good job in slowing global warming with relatively little effort/cost invested, but for political reasons won't see the light of day until they become a last resort, far too late in the game. I can imagine humans a century from now wishing we had deployed them sooner and prevented so much unnecessary destruction.