Why a book on the Medieval Warm Period?
Some years ago, I wrote a book on the Little Ice Age, which began in the fourteenth century A.D. and ended in about 1860. I became aware of the Medieval Warm Period during the research for that book, but only really began to think about it when the furor over global warming picked up two or three years ago. When I looked into the literature, I realized that the warm centuries between A.D. 1800 and 1200 had important implications for our world. What are these implications? When I started my research, I assumed that the Medieval Warm Period was essentially a European phenomenon. But I soon discovered that, while the warm centuries were beneficial to Europe, they were near-catastrophic elsewhere, especially in the tropics, where drought accompanied greater warmth. If there was modest warming during the Medieval Warm Period, presumably the effects would be immeasurably greater in an era of greater warming. Drought is an invisible killer, what in the book I call the “silent elephant in the
