You might have heard snippets of conversations about food and water shortages, changing climates, and other worrisome topics. If you've brushed them off as unimportant or unrealistic, you might want to reconsider that. If you think that humans are too small to impact their environment or cause disasters, consider this — it's already happened.
During the 1930s, when the Great Depression was already wreaking havoc on the lives of millions, a series of droughts hit the American prairies. The droughts were simply natural events, but the damage done to the land — and subsequently to the residents' lives — could have been easily prevented.
Clouds of dust enveloping entire towns was a common, if not a daily occurrence throughout the Southwest in the '30s. Droughts caused the topsoil, loose from overfarming, to blow away.