Impacts of climate change on drought: changes to drier conditions at the beginning of the crop growing season in southern Brazil

Autor(es)

Pereira, Vania Rosa ; Blain, Gabriel Constantino ; Heuminski de Avila, Ana Maria ; de Matos Pires, Regina Celia ; Pintos, Hilton Silveira

• Tipo de documento: Artigo Científico
• Fonte: Bragantia; v. 77, n. 1, p. 11-pg., 2018-01-01.

Resumo

The intensification of drought incidence is one of the most important threats of the 21st century with significant effects on food security. Accordingly, there is a need to improve the understanding of the regional impacts of climate change on this hazard. This study assessed long-term trends in probability-based drought indices (Standardized Precipitation Index and Standardized Evapotranspiration Index) in the State of Sao Paulo, Brazil. Owing to the multi-scalar nature of both indices, the analyses were performed at 1 to 12-month time scales. The indices were calculated by means of a relativist approach that allowed us to compare drought conditions from different periods. The years 1961-1990 were used as the referential period. To the authors' best knowledge, this is the first time that such relativist approach is used in historical trend analysis. The results suggest that the evapotranspiration rates have intensified the regional drought conditions. The time scale used to calculate the indices significantly affected the outcomes of drought trend assessments. The reason behind this feature is that the significant changes in the monthly regional patterns are limited to a specific period of the year. More specifically, virtually all significant changes have been observed during the first trimester of the rainy season (October, November and December). Considering that this period corresponds to critical plant growth stages (flowering/regrowth/sprouting) of several major crops (e.g. Sugarcane and Citrus), we may conclude that these significant changes have increased the risk of crop yield reductions due to agricultural drought. (AU)

• Processo FAPESP: 13/15434-6 - Modelagem de padrões de precipitação e temperatura e suas relações com mecanismos climáticos: um subsídio para avaliar os impactos na produtividade da cana-de-açúcar
• Beneficiário: Vânia Rosa Pereira
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado