Town Hall Seattle Science Series

The Sahara desert, once upon a time, wasn’t a desert at all. It was green. It was a pleasant place, fed by rivers and lakes. It was home to crocodiles, hippos, turtles, and fish of all stripes. Prehistoric hunters and gatherers came to the lush land, as well, to partake of its rich bounty. It’s now the largest hot desert in the world, equal in size to the United States. Temperatures can reach upward of 130 degrees and sand dunes can climb to nearly 600 feet in height. All this begs the question: What happened? Martin Williams, in When the Sahara Was Green: How Our Greatest Desert Came to Be, helped answer this question, and asks many more. A time-traveler, of a sort, Williams went back millions of years to showcase the rich history of earth’s greatest desert. Why did its climate change? Did it really have forests roamed through by dinosaurs? How has all this impacted human populations? Will the desert ever return to that verdant Eden? And what will climate change do to the desert? He also brought to the fore