Scientific American: Although Eban Goodstein has been educating people about the global-warming threat for a decade, he only recently took major action to help solve the problem. In 2006 he heard James E. Hansen, a leading climate scientist at the NASA Goddard Institute for Space Studies, say that global warming could prove catastrophic sooner than anticipated and that the world needed practical solutions immediately. Goodstein, an economics professor at Lewis and Clark College, temporarily left teaching …