The Great Ocean Conveyor

Book excerpt: Exploring the link between the ocean's currents and rapid climate change Wally Broecker is one of the world's leading authorities on abrupt global climate change. More than two decades ago, he discovered the link between ocean circulation and climate change, in particular how shutdowns of the Great Ocean Conveyor—the vast network of currents that circulate water, heat, and nutrients around the globe—triggered past ice ages. Today, he is among the researchers exploring how our planet's climate system can abruptly "flip-flop" from one state to another, and who are weighing the implications for the future. In The Great Ocean Conveyor, Broecker introduces readers to the science of abrupt climate change while providing a vivid, firsthand account of the field's history and development. Could global warming cause the conveyor to shut down again, prompting another flip-flop in climate? What were the repercussions of past climate shifts? How do we know such shifts occurred? Broecker shows how Earth scientists study ancient ice cores and marine sediments to probe Earth's distant past, and how they blend scientific detective work with the latest technological advances to try to predict the future. He traces how the science has evolved over the years, from the blind alleys and wrong turns to the controversies and breathtaking discoveries. Broecker describes the men and women behind the science, and reveals how his own thinking about abrupt climate change has itself flip-flopped as new evidence has emerged. Rich with personal stories and insights, The Great Ocean Conveyor opens a tantalizing window onto how Earth science is practiced.