Well, it's not really a problem now. Spring came a month early, but who cares? Islands aren't underwater yet, there's plenty of food in first world countries (who would be paying for this) and there's no serious drought. From a politician's point of view, you're proposing to spend billions or trillions to solve a problem that we're still only seeing hints of (with an extremely first-world centric view, of course).

If the technology works, why not wait until the people demand it, instead of telling them they have to feel the pain of paying for it now to solve a problem no one can see?