It was not that many years ago that one could reasonably defer judgement about global warming. But the evidence that our planet's climate is changing at a pace that can only presage disaster is becoming so compelling that only the US executive branch can't see it. Even the Bush administration now acknowledges that there may be a problem, but not one that would require significant action. This essay in three installments by Elizabeth Kolbert (who also wrote the New Yorker "Ice Memory" story that was my Pick in January of 2002)begins with reports from the arctic, where some of the most dramatic evidence is found - in the shortening of the winter season, a dramatic decrease in ice cover of the ocean, and the rapid motion and melting of glaciers. The decrease in the amount of ice and snow makes the earth much more absorbent of the sun's energy, which causes more melting, which decreases the albido further, which melts more, in a continuous and possibly irreversible cycle. In part II, historical evidence for rapid climate change is combined with an explanation of how computer models of the atmosphere help us to understand long-term trends, and to predict what will happen in the future. Part III examines the practical and political implications of global warming. As the oceans rise, due both to increased melting and the thermal expansion of water, what will happen to the Netherlands, New Orleans, or the low-lying islands of the Maldives that came to our attention as a result of the recent Tsunami disaster?