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.

For me science is not different from art, except in the one small, crucial detail that experiments speak their own truths, not ours.

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.

There are probably already too many people on the planet.

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.

New molecular methods that add or modify genes can protect plants from diseases and pests and improve crops in ways that are both more environmentally benign and beyond the capability of older methods.

Even as the population doubled from three to six billion, we managed to race ahead with all kinds of technological and scientific events in agriculture - from using more fertilizers to mechanization to advanced plant breeding.