One you cut population.
Two you try to feed the population you get.
Oh, and let's not forget the power of food prices to bring down governments. The "Arab Spring", the domino ;like coillapse of so many hardline regimes in the Middle east is as much to do with rising food prices as anything else, something the activists intent on a new world order will not have neglected to note. If you can bring down even totalitarian states this way, how hard can it be in a western economy? You just have to force things to the tipping point. Westerners can probably afford to pay a lot more for food before they reach for their burning torches and farmyard implements and march on parliament to clean house.
One money maker will be GM crops though it is hard to predict which side of the debate that will end up as the Greenies have been rather anti-GM.
I guess, given the popularity of GM with politicians (all those campaign contributions?) the GM crop people are as natural a target for the greenies as Big Oil.
But if we have a big population and pressure on food resources (ironically, much from bio-fuels)they ought perhaps to support GM crops - rather like the Bird Watcher people supporting, initially, bird dicing wind farms.
But there will be lots of grant money on GM and agricultural research, that's for sure.
So the "smart money" will probably be invested in buying up land. Any land. Even deserts. Yes, there will be reclamation schemes and the like. The scope for "academics" is pretty much on par with climate change. It will just be a different set of academics figuring out which side their bread is buttered on and we'll pretty soon get an idea of whether science is just as corruptible here as with climate (though the "deniers" will have learned some lessons too).
Oceans, (food) and population. I'm pretty sure we can come up with lots of money making scams/projects if we put our minds to it but perhaps the easiest thing to do is keep an eye on where the BBC pension fund and the WWF money is going.
But I think I may have to dig out my Club Of Rome paperback and see what other doomsday scenarios they have listed. I'd not like to get caught off base if they suddenly decide on some other "project".