>Without it the world can still grow crops (we SOMEHOW have for thousands of generations).

Historical yields were tiny compared to what we get from contemporary farms. I don't know if we need Roundup in particular, but if we went back to traditional farming methods half the world would starve.

There's no going back.

Actually there is no evidence of this, a good proportion of of the food produced is actually used to feed animals which is the most inefficient way to produce food.

Just by eating less meat (which makes sense because we are not supposed to eat so much meat), suddenly we don't need to product so much. The actual price of the food is so low currently that what you pay in a supermarket is mostly the externalities. Switching to cleaner methods would not lead to starvation providing that we would eat differently.

Most americans would happily choose cancer over vegetarianism. That part isn't Monsanto's fault. Source: I am a vegetarian who talks to omnivores and near-carnivores.

Yeah, that's the main problem I guess, the system is providing people what they want but not what they need. It works like any other market, the consumers want cheap meat so the industry is providing cheap meat. The whole industry is then shaped to solve the wrong problem. They don't even need to fully switch to vegetarianism for it to work but they need to understand that eating meat once in a while is healthier and more reasonable than having a diet based on eating meat every day.

What about when the population doubles, and then doubles again?

http://geneticliteracyproject.org/wp-content/uploads/2015/01...

That's very unlikely. The global population is probably going to peak mid-century and then go down.

Is it? Where do you see that trend?

http://cdn.phys.org/newman/gfx/news/hires/worldpopulat.gif

It's more about what we are willing to eat than what we grow, diets high in meat require lots of arable land and energy to create.

Everything is optional at some level.

You need to do a cost/benefit analysis, not reject methods that could cause any number of deaths ever.

Because all methods cause some number of deaths in some circumstances.

Numbers need context if you're going to make the right decision.