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.

Jumping genes are fundamental because they're agents of change. Everybody knows that organisms evolve. What makes them evolve is that their genes are dynamic and in motion. A familiar example is the stripe-y corn - called Indian corn - that you buy in the fall.

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 have six-and-a-half-billion people on the planet, going rapidly towards seven. We're going to need a lot of inventiveness about how we use water and grow crops.

If there are more and more environmental refugees, they are going to end up on your doorstep too.

The more we can grow on already cultivated land, the better.

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.