2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM

Paper No. 3
Presentation Time: 8:55 AM

Multiple Causes of the Dust Bowl

LEE, Jeffrey A., Economics & Geography, Texas Tech University, PO Box 41014, Lubbock, TX 79409-1014 and GILL, Thomas E., Geological Sciences Department and Environmental Science and Engineering Program, University of Texas at El Paso, 500 West University Avenue, El Paso, TX 79968, jeff.lee@ttu.edu

Wind erosion was severe on the Southern Plains in the 1930s, a time and region known as the Dust Bowl. In the intervening decades, many have attempted to classify the Dust Bowl as either a natural or an anthropogenic disaster. We argue that it was most likely a convergence of both, and not uniquely caused by any single factor.

CLIMATE: The extreme 1930s drought may have resulted from a synchronous combination of decadal-scale Atlantic and Pacific temperature cycles and a breakdown of the ENSO. However, other modern droughts of the same relative intensity did not result in comparable amounts of wind erosion. Increased intensity of lee cyclones may have caused more persistent and stronger winds during this drought.

SOIL MANAGEMENT: “Dust mulching”–reducing evaporation of soil moisture by keeping a layer of fine dust on the soil surface–may have been effective in water conservation, but greatly increased soil wind erodibility.

ECONOMIC AND DEMOGRAPHIC FACTORS: In the relatively wet 1920s, much marginal land was converted to agriculture due to high crop prices. Investment in newly-developed mechanized farm equipment also encouraged expanded cultivation while also increasing farmers' debt. When drought killed crops, farmers lacked funds for land management. Still, previous and subsequent economic recessions, crop failures, and changes in farming practices in the Great Plains were not accompanied by “Dust Bowl” conditions.

None of these factors alone can clearly be said to be the “cause” of the Dust Bowl; this catastrophe likely was the result of a synergy between human and natural factors. We must learn lessons from the 1930s Dust Bowl to avert future potential disasters associated with climatic and technological changes to Great Plains agriculture.