Every time we do something to change the world and someone says "It's not a problem.", they're usually wrong.
Weeds don't leach nutrients. They make it hard for the farm machinery to do it's job. They also help support insects, slow evaporation, and support an ecological system that helps support the crop plants. Web of Life Good. There is a problem where we take too much from the soil, and we have to do crop rotation and let fields go fallow to get that back in. We have to fertilize. We have to grow some legumes and let them put nitrogen back into the soil... Frankly, we use herbicides because it's easier and we're lazy, not because they're a better solution.
And the genes for producing pesticides get out into the wild and the insects develop resistances. It IS happening. Refuges help, but... Then there's the side effects. :D Most pesticides mess up the neurological systems of bugs. Including all the beneficial bugs....
GM crops absolutely produce more food per acre than Dumb Farming. Smart farming however? http://www.motherjones.com/env...
No tilling and good usage of cover crops does wonders... We only ever tilled because it made it easier to drop seeds in, and we thought it would help mix fertilizer into the soil. turns out it just disrupts the systems in the soil and makes fields prone to erosion.
I don't think it's fear mongering to point to what we KNOW is happening, and what WILL happen. I don't think it's fear mongering to point to alternative methods that work just as well and have less side effects and say "Hey! this is way better!". And we don't have a problem producing food. Famines are a food distribution problem, not a food production problem. If you want to fight famine, educate small farmers in poor countries on sustainable methods. Or, you could sell them patented seeds, and then patented chemicals, and then put them in debt forever.
Read the link.