About 2.3 million people worldwide are directly or indirectly employed in renewable energy-fields-and the greatest employment gains have occured in countries in which the government supports renewable energy,according to a recent Worldwatch institute study. * President Obama has emphasized thatsustainability and clean energy are vital elements in sucessfully rebuilding the U.S. economy and securing more jobs. And because renewable energy sources are commonly more labor-intensive than fossil fuel sources, a transition to renewables promises job gains. Peterson's Green Careers in Energy pinpoints the best opportunities in the fast-growing and most promising renewable energy fields-solar, wind geothermal, hydroelectric and marine, biofuel, and hydrogen-with data on colleges,organizations, and institutions that offer courses,degrees,certification, and training/retraining.