For 15 years, Worldwatch Institute has published "State of the World." It's the groups' annual report card on the health of the planet; noting some of the most pressing global problems and suggesting solutions. In this year's edition, Worldwatch President Lester Brown describes a global economy that's strong, but also straining the earth's natural systems. He calls for a new kind of economy that's both vibrant and sustainable, the antithesis, he says, of the current western business model. Lester Brown is president of Worldwatch Institute in Washington, D.C..