Solving CO2 ?

...the increase of CO2 we've caused, from 280 to 385 ppm, is already enough to get us into the danger zone... we probably James Hansen, Ph. D.have to decrease CO2 at least back to 350... closer to what it was before we started messing with the system.
But that's still possible, because... our agricultural practices could be modified to bring CO2 back down much more quickly: it's a natural type of ego-engineering... to get this CO2 back where it came from — and that, I think, will be an important part of solving the problem.

—James Hansen, Ph. D.
NASA Godard Institute for Space Studies