Joel Achenbach of the Washington Post is at the Aspen Environment Forum. He says : A question in the air: Are you an optimist or a pessimist? You have to figure out how to feed 7 billion people reliably (a billion right now are going hungry or have inadequate nutrition; 3 billion live in poverty on less than 2 dollars a day), and give them clean drinking water, and sanitation, and then factor in population growth of an unknown degree (will we hit 9 billion? 10? 16?), and then factor in ...