One of the consequences of lazy, defeatist mainstream discussion of climate change (see: Robert J. Samuelson) is goofballery like this piece in The New York Times. Michael Fitzgerald argues that because we don't yet have a weapon that can totally and awesomely kick global warming's ass, we should spend billions of public dollars on giganto-technologies like carbon sequestration and space-age masturbation aids like light-reflecting space particles.
This is stupid. We have dozens, hundreds of ways of cutting GHG emissions available right now. We have technological tools; we have social, economic, legislative, and regulatory tools. I'd bet we could get the U.S. to zero (or trivial) emissions by the last quarter of this century, especially if we spent all those billions wisely. And we'd improve our quality of life doing it. Once we start doing it, other countries will follow.
Maybe we couldn't get all the way there with today's technology. But the distance between "where we are" and "where we could get using today's technology" is chasmic. While we're traversing that distance, technology and civil society will not be standing still. By the time we get where we thought we could get, we'll be able to get much farther. I very much doubt there will ever come a time when we stop and say, "we've reduced our greenhouse-gases the maximum amount possible with our existing technology."
In other words, the thing to do is just get fucking started, in earnest. Throwing up our hands in despair and waiting for a deus ex technologica is comically, grotesquely premature. It's like deciding you'll never finish the marathon before you're done scratching your ass in front of the bathroom mirror.
The lack of means is not the problem. The problem is the lack of collective will.