What about organic farming to help mitigate CO2? It doesn't seem to be discussed as much as a solution, but it addresses a great way to fight climate change. According to the Rodale Institute, converting 2 acres from conventional to organic farming is equal to taking 1 car off the road.
http://www.rodaleinstitute.org/files/Rodale_Research_Paper-07_30_08.pdf
and there is more research here:
http://www.rodaleinstitute.org/global_warming
I realize that most of us here are not farmers, but if we purchase more organic food, the market will follow and if these large farms convert, it seems that it would certainly help get to 1990 levels.