I am afraid we are missing something here. The world is still emitting 80 million tons of carbon into the atmosphere every day. So it will get worse next year. And if we lose the Arctic ice caps, Global Warming could become unstoppable (see
http://thinkprogress.org/climate/2012/08/26/745571/why-the-arctic-sea-ice-death-spiral-matters/).
We are not going to save ourselves with GMO crops. We have to reduce our carbon emissions to zero and then wait 200 years for the carbon levels to come down.