Debating climate change frequently involves maps and projections of the impact on coastlines. The best historical examples are the impacts of the Ice Ages. Worries about droughts cause concerns for desertification, but most people simply assume that the rains will eventually return. The Sahara is providing excellent examples of how quickly fertile land can become dunes and deserts. New data shows that as recently as 5,000 years ago (a time when many civilizations were being born) the Sahara had active river basins fed by monsoon-style rains. Whether humans had anything to do with the change or not, the speed of the change and the extent of the change demonstrates how quickly and severely arable land can turn to sand.
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