### Catastrophic drought is coming back

There are two kinds of historians, Brian Fagan says, parachutists and truffle hunters. Parachutists command an overview of the landscape, while truffle hunters dig deeply to uncover marvelous treasures. Fagan is a parachutist. In his talk Fagan emphasized a wide view of human history as it unrolls in the landscape of climate. In our lookout from the parachute, we can see evidence from ice cores, tree rings, fossil pollen, and historical records, all pointing to the conclusion that people in the past have suffered through global warming periods before. So what happened?

Using data from truffle-hunting historians, Fagan told of how vineyard harvest records in Europe show that England became so warm during the period between 800-1250 AD that England not only had vineyards in its central provinces but it also exported wine to France. The medieval warm period had repercussions throughout society. Iceland and Scandinavia warmed up enough to grow cereal crops, tree lines elevated in mountain areas, and there were longer growing seasons everywhere on the continent.

This warming up of agriculture initiated the first vast clear-cutting of European forests. In the short 200 years between 1100 and 1300, from one-third to one-half of European wooded wilderness was deforested to make way for fields and pastures -- shaping the lovely farm scenes we now associate with Europe. (Today only Poland has any remaining virgin forests).

Fagan says the myth of the medieval warm period is that it was warm. There were all kinds of weather extremes. In 1315 it started to rain for seven years. The newly cleared and naked hills eroded, dams burst, disease spread, and prolonged drought followed.

And not just in Europe. Mesoamerica was jolted by long droughts. The Mayan pyramids at Tikal were engineered to act as water collection reservoirs. The collapse of their empire, and others in South America such as the Inca in Peru, are correlated to prolonged droughts.

Indeed, says Fagan, the elephant in the climate room is drought. As recently as the 1800s, prolonged droughts killed 20-30 million people in India during the British Raj period. We have a tendency to believe that modern technology has alleviated our susceptibility to drought, and it has -- except for the billions of people on earth today who are living as subsistence farmers.

It is upon these people that Fagan wanted us to focus our attention and care, because it is upon these people that the most serious consequences of global warming will fall. Referring to his own experience of many years as an archeologist in Africa, he painted a vivid image of what a severe drought entails and how a drought can act like a cascading disruption and rapidly destroy a vibrant culture to the point where it disappears completely.

Forget the rocketing "hockey stick" of global warming, he urges. Even mild climate warming produces prolonged droughts, and we should expect more of them. There's already been a 25% increase in droughts globally since 1990. In the next 100 years, we can expect the number of people to be affected by droughts to rise from 3% of the world's population to 30%.

The lesson Fagan wanted us to leave with was that the effects of global warming will be felt greatest on marginal land and marginal peoples -- many far from the sea and rising sea levels - and that because of their marginality, the consequences of prolonged drought will not just be inconvenient, but devastating.

In the question and answer period, he was asked what the stricken people can do about it? "Move," he said, "is the only option." If the world is heating up, where would he move to? "Canada. It will be dryer, much warmer, and their politics are reasonable."