The Roger Revelle Commemorative Lecture Series was created by the Ocean Studies Board of the National Academies in honor of Dr. Roger Revelle to highlight the important links between ocean sciences and public policy. Nancy Rabalais, the twelfth annual lecturer, spoke on March 29, 2011, at the Baird Auditorium, Smithsonian Institution, National Museum of Natural History. © 2011 by The Oceanography Society. All rights reserved.