@maxdancona,
If a train is speeding along the track toward a cliff, the biggest need is not more fuel for the engine.
I believe there should be a "Manhattan project" for sustainability, world-wide, in terms of energy, resources, food, and water. In the US, that would prohibit such things as draining the Ogalala aquifer with no end in sight just to produce an ever increasing quantity of corn drenched with chemical fertilizers and herbicides.
This does indeed mean less agribusiness-produced food, and would in turn dictate variable caps on population. Though people won't like it, the birth rate in areas with poor land would necessarily need a harsher cap than in large fertile lands. Bangladesh is not sustainable at the same rate as the US. Population controls would consequently need to be taken far more seriously than even China's one child policy, since China's population is still growing at a dramatic rate despite 35 years under the "one child" policy. The extreme measure of population control might be something like what is practiced with cats in the US, which are typically spayed as kittens.
For humans in a region that needs to reduce population dramatically, a reversible sterilization procedure would be ideal; administered to pretty much every child. They can then apply for a permit to have the sterilization reversed later in order to have a child when and if they wish to. It's not such a strange idea to have to apply to have a child, it USED to be standard procedure in the USA; marriage served a gatekeeping function, as responsible adults first applied for a license, asked for parents' blessings, and established financial security (often including dowries, hope chests, and home ownership) before having babies.
Sustainable food production can also mean that a much larger portion of the population becomes involved in some way in producing food, with backyard and rooftop gardens, for instance. This is also not a strange idea; it was standard practice in the US and Europe during World War II, for instance.
The ever larger agribusiness approach actually thrives upon runaway population and it self-reinforces through shady practices, because it's "good for business" from their perspective. GMO crops are rarely developed to improve taste or nutrition (except in rare instances such as the GMO banana the Gates foundation has funded), they are more typically engineered to increase the profits of the companies that produce them. The ideal corn from their perspective is one that not only produces corn, but is engineered to require use of THEIR fertilizers and herbicides, and produces sterile seed, so that you have to buy new seed from them each year. Have a look at the patents, for instance "Roundup-ready" and "Terminator" GMO plants, and you'll see.
http://www.google.com/patents/US5554798
http://www.viewingspace.com/genetics_culture/pages_genetics_culture/gc_w03/terminator_abc/terminator_seed.htm