Linking Sustainable Indices and Climate Variability in the State of Ceará, Northeast Brazil

Abstract

The underlying source of climate variability affecting the Ceararain-fed agricultural production in Northeast Brazil is the interrelatedglobal-scale fluctuations of sea-surface temperature (SST) in thetropical Pacific and Atlantic regions. Despite the elevated skill inseasonal climate forecasts for rainfall in Ceara, models linking SSTanomalies (SSTAs) in the tropical Pacific (Nino 3.4 index) and Atlantic(Dipole index) regions to crop production are not well developed. Theresults of this study show that clear connections among episodes ofdrought patterns and maize and bean production and yields over the rainyseason result from seasonally changing SSTAs. Total seasonal maize andbean production are inversely correlated with Nino 3.4 and AtlanticDipole indices, while maize and bean yields are directly correlated withNino 3.4 and Atlantic Dipole indices but inversely correlated with maizeand bean yields averaged from February to April. Year-to-year averagedFebruary-April SSTA fluctuations explain about half the interannualvariability in maize and bean production over the rainy season. Therewere two fluctuation shifts (from 1974 to 1981 and from 1984 to 1997,with a transition during 1982-1983) of the maize and crop production andyields that were largely in-phase with seasonal SSTAs. However, themagnitude and duration of extreme El Nino-Southern Oscillation (ENSO)and Atlantic Dipole effects on Ceara crop production and yieldsindicated by the vulnerability index offers some strong policy warnings.