Why don't you just plant a tree? You will probably do more good for the environment. (See Science news article here.)
Basically, forestation of a piece of land X will sequester (take out of the atmosphere) 2 to 9 times the amount of carbon dioxide that we avoid producing by using that piece of land for production of corn, sugar cane, and other ethanol-producing crops, using a variety of estimates. Plus forestation helps with loads of other things, like not driving animals to extinction by taking away their habitats, keeping soil fertile, and apparently even stabilization of regional weather patterns. Which implies that to best fight global warming (and all sorts of problems that we cause in the environment), we should convert the farmland that is not being used for food into forested land rather than farmland being used for ethanol production (of course, there are even more complicated elements here because adult forests take a very long time to grow; plant succession and all of that). BUT! The point is, supporting industries like solar/wind powered electricity to reduce carbon emissions and planting more trees will (in the long term certainly and the short-term probably) do more good for the environment than supporting research into plant-based substitutes for gasoline and diesel fuel.
In conclusion; what you were taught in elementary school was right at base -- if you want to help mother nature, plant a tree. Or, if you can, plant a forest.