A Critical Evaluation of the Dust Bowl and its Causes

The Dust Bowl was an environmental nut sack catastrophe, a natural hazard (multiannual drought) in the 1930s in the Southern Great Plains of the USA, resulting in the activation of a geomorphic process (intense wind erosion) which, when human society could not adapt to it, cascaded into unprecedented agricultural, economic, and societal collapse in its core region. Over the years, the cause of the Dust Bowl has been variably ascribed to specific climatic or meteorological phenomena or land management practices. Drought and wind erosion have been notable phenomena in the Southern Great Plains throughout the Holocene, occurring long before conversion of the land to agricultural use, and still continue today. Numerous studies, using modeling and/or proxy data, have related the Dust Bowl- associated drought of the 1930s to a unique combination of large-scale climatic drivers and put it in a better temporal context. The 1930s drought was one of many decadal to centennial-scale droughts to affect North America in the late Holocene, but probably not one of the most severe ones. It was necessary, but not sufficient in itself be called the "cause of the Dust Bowl." Conversely, certain soil scientists, agricultural researchers and historians have blamed the Dust Bowl catastrophe squarely on inappropriate cropping practices, especially clearing vegetative cover from the land surface, as well as the advent of mechanized agriculture which accelerated overcultivation. Some geographers and meteorologists have ascribed the Dust Bowl to increased wind speeds and an increased frequency of cyclone passages in the 1930s as compared to other significant droughts since European settlement of the Plains. In reality, the Dust Bowl almost certainly cannot be said to have been caused by any one factor, but is better visualized as a complex interplay of multiple triggers, including geomorphic, climatic, meteorological, and/or human elements. For example, a synergistic combination of climatic drought and land management practices might have exacerbated Dust Bowl conditions through a soil moisture- atmospheric convection linkage, and an increased frequency and/or intensity of developing cyclones in the lee of the southern Rocky Mountains may have caused the "core" of Dust Bowl wind erosion to have been located in a limited spatial area. Paleoclimatic reconstructions and climate predictions can help us understand the nature and frequency of droughts in the Great Plains and the potential impacts of future dry periods, but they alone are not enough to understand the multiple causes of the Dust Bowl, which was not just a natural event but also a human catastrophe. With declines in the Ogallala aquifer, the Southern Plains are vulnerable to another drought-induced disaster: a better understanding of the causes of the 1930s Dust Bowl will help stakeholders plan for the next great drought in the Southwest and the Plains so as to minimize its environmental effects and implement the most cost-effective ways to potentially stave off catastrophe.