Einstein Science Reporting for Kids
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19-Mar-2004

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American Association for the Advancement of Science

What caused the 1930s dust bowl?



A wall of dust approaching a Kansas town. Image courtesy of NOAA/Historic NWS Collection.
Click here for a high resolution photograph.

A severe drought parched the Great Plains during the 1930s, driving farmers off their land in search of work. The drought, plus the farming methods of that time, led to "black blizzards" of dust that rolled across the plains. Why was this drought so widespread and long-lasting? And, could it happen again?



Dust and sand heaped up against fence windbreak. Image courtesy of NOAA/Historic NWS Collection.
Click here for a high resolution photograph.

A first step toward answering these questions is to figure out what caused the drought to begin with. Siegfried Schubert of NASA Goddard Space Flight Center and his colleagues now think they know the answer.

Using a computer climate model, they discovered that unusual sea surface temperatures in the tropical oceans were probably to blame.



An approaching dust storm in Kansas, 1935. Image courtesy of NOAA/Historic NWS Collection.
Click here for a high resolution photograph.

These ocean changes may have kicked off a series of climatic events that eventually disrupted the flow of moist air over the Great Plains, the authors suggest. These findings appear in the 19 March issue of the journal Science.

Recent climate change caused by human activities makes it difficult to predict the likelihood of such a drought occurring again in the near future. But, evidence from tree rings and lake sediments does suggest that droughts lasting even longer than the Dust Bowl have occurred in the Great Plains approximately once or twice a century for the last 400 years.

Our farming methods have improved though, so fortunately "black blizzards" are probably a thing of the past.

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