James J. McCarthy, professor of biological oceanography at Harvard University, addresses the long-standing and pervasive myth that human input is local not global. He argues that damage to the earth's polar areas might finally be proving just how wrong this type of thinking is. The Southern Ocean, the body of water surrounding Antarctica, is a key region in determining global climate. Recent studies show that the Southern Ocean is undergoing an alarming warming trend that may affect climates in the Pacific, Atlantic, and Indian Oceans. What is the Antarctic telling us abut our future? In the north, the Arctic also is changing in dramatic and disturbing ways with giant lakes replacing what used to be ice fields. Are the polar areas of our earth especially sensitive? If so, do they now serve as an early warning system for catastrophic change?