In agriculture, people have taken wild plants that can't be eaten by people - and turned them into wonderful food sources. And that's because genomes can change, and people working with plants have picked mutations. Mutations are nothing more than genetic changes.

We have domesticated crops over a very long period of time, like tens of thousands of years. And crops get - seeds get carried. Sometimes, if they're very small seeds, they get scattered off trucks. Pollen travels.

There's almost no food that isn't genetically modified. Genetic modification is the basis of all evolution. Things change because our planet is subjected to a lot of radiation, which causes DNA damage, which gets repaired, but results in mutations, which create a ready mixture of plants that people can choose from to improve agriculture.

In many places in the developed world, we eat or waste probably twice as many food calories as we really need. We're wasteful of food. We ship all over the world. We're now realizing that generating the energy to ship the food around the world is also ruining our climate.

We've gotten so good at growing food that we've gone, in a few generations, from nearly half of Americans living on farms to 2 percent. We no longer think about how the wonderful things in the grocery store got there, and we'd like to go back to what we think is a more natural way.

We are sliding back into a dark era, and there seems little we can do about it. I am profoundly depressed at just how difficult it has become merely to get a realistic conversation started on issues such as climate change or genetically modified organisms.

We wouldn't think of going to our doctor and saying 'Treat me the way doctors treated people in the 19th Century', and yet that's what we're demanding in food production.