Summary

The semi-arid interior of Brazil’s northeast region, known as the sertão, has long been subject to droughts. These can devastate the agricultural and ranching economy and cause serious hardship for the area’s inhabitants, particularly those who labor on farms and ranches belonging to the landowning elite. A prolonged drought in the late 1870s led the Brazilian government to begin soliciting advice from engineers about how to redress the periodic crisis. In 1909 the federal government established a permanent federal agency, the Inspectorate for Works to Combat Drought, to undertake reservoir construction throughout the sertão along with other measures that would alleviate future droughts. In subsequent decades the activities of the drought agency expanded to include constructing irrigation networks around reservoirs and establishing agricultural experiment stations to teach sertanejo farmers improved methods of farming in semi-arid conditions. Although powerful landowners lobbied for federal aid to construct reservoirs, which helped to sustain their own cattle herds through drought years, they were often opposed to initiatives like the establishment of irrigated smallholder colonies around reservoirs, which threatened to alter the social order in the sertão. Support for the federal drought agency’s work waxed and waned during the 20th century under different presidential administrations. Often it would rise in response to a period of damaging drought, then diminish once the crisis abated.

Droughts have affected the sertão at irregular intervals since at least the colonial era. They vary in temporal duration and geographic expanse. Their impact on human populations depends on how the area of reduced rainfall overlaps with human settlement patterns and land use. Over the 20th century the years in which drought most severely impacted human communities (including crops and livestock) in the sertão included 1915, 1919–1920, 1931–1932, 1942, 1951–1953, 1958, 1970, 1979–1983, and 1998–1999. These are the periods when local, state, and federal governments received the most persistent pleas for assistance from affected populations. The precise cause of droughts in the region is debated, but they are thought to be triggered by changes in major wind patterns, particularly the El Niño Southern Oscillation (ENSO), that prevent Atlantic Ocean precipitation from reaching the sertão.