Journalist and professor of environmental studies Donella Meadows. Twenty years ago she co-authored the book, "The Limits to Growth." The book used a computer model to project the impact of growth on the environment. It caused a sensation because of it's eco-gloom and helped spur the environmental movement. Now in the authors' sequel, "Beyond the Limits," they argue that we have shot past the earth's limited resources but that we are in a better position to avoid global economic collapse because of new technical possibilities.