eGrapes of Wrathf drought explained
The Dust Bowl droughts that ruined millions of Great Plains farm families in the 1930s were triggered and sustained by barely perceptible temperature changes in oceans thousands of miles away, according to a new NASA study. Computerized climate simulations suggest that abnormally warm water in the tropical Atlantic set up wind circulation changes that cut off the flow of moisture from the Gulf of Mexico during the summer and fall. At the same time, unusually cool sea-surface temperatures in the tropical Pacific set up global patterns that suppressed storm development on the Plains. The combination, scientists said, led to persistent drought and what many observers regard as the worst US natural disaster of the 20th century. The pattern has not recurred, and no Great Plains drought since has been as severe. But that might be only a matter of time, said Siegfried D. Schubert ofNASAfs Goddard Space Flight Center. Therefs no reason to believe wefre not going to have another drought like that, said Schubert, a co-author of the study published in the journal Science. Therefs evidence going back at least 400 and even 1,000 years where theyfve been able to show these mega-droughts tend to occur once or twice a century.