If it were possible to flip a switch and convert farms (including factory farms, family farms, and subsistence farms) across the world from traditional methods to organic methods, would there be enough land, labor, and infrastructure, to produce the amount of food necessary to feed the world? If so, would the majority of people still be able to afford enough food?

What research has been done to determine if organic practices (which are clearly more sustainable from an environmental perspective) are also more economically sustainable?

One of the key contentions in the on-going debate about GMOs is that such technology is necessary to feed the world. A common counter-argument is that widespread application of organic farming and permaculture can do the job better, with less risk. I'm wondering if this is true, without requiring a utopia where everyone maintains a rooftop garden.