It's a funny thing these days; there are two "optimistic" camps. One that says that social change is impossible, but technology can save us, and the other that says that we have no real near-term technological fixes, but we can be saved by large-scale changes to society. In an irony that would be delicious if it weren't so existentially terrifying, I think they are both right and both wrong, but not the way we'd wish.

Building out technology that we already have can save us. We just need to agree to pay for it, which we can't because some of us are too poor to make changes required, some of us are apathetic, some of us are actively antagonistic (think coal rollers and such), and some of us are ignorant (willfully or otherwise). Like all large-scale problems, it's the people who are in the way, not tech.