Freshwater scarcity has increased at an alarming rate worldwide; improved water management plays a vital role in increasing food production and security. This study aims to determine the water footprint of Brazil’s national food consumption, the virtual water flows associated with international trade in the main agricultural commodities, as well as water scarcity, water self-sufficiency and water dependency per Brazilian region. While previous country studies on water footprints and virtual water trade focused on virtual water importers or water-scarce countries, this is the first study to concentrate on a water-abundant virtual water-exporting country. Besides, it is the first study establishing international virtual water trade balances per state, which is relevant given the fact that water scarcity varies across states within the country, so the origin of virtual water exports matters. The results show that the average water footprint of Brazilian food consumption is 1619 m³/person/year. Beef contributes most (21%) to this total. We find a net virtual water export of 54.8 billion m³/year, mainly to Europe, which imports 41% of the gross amount of the virtual water exported from Brazil. The northeast, the region with the highest water scarcity, has a net import of virtual water. The southeast, next in terms of water scarcity, shows large virtual water exports, mainly related to the export of sugar. The north, which has the most water, does not show a high virtual water export rate.

In Brazil, the Northeast region, particularly the state of Pernambuco, is prone to extreme hydrological events, especially episodes of heavy rain and long periods of drought. This study examined the spatiotemporal variability of rainfall in Pernambuco and the occurrence of extreme rainfall events. In this study, the following climate indices were used in daily rainfall data from the historical series from 1990 to 2020: (a) the Precipitation Concentration Index (PCI), (b) the Standardized Precipitation Index (SPI), (c) the Precipitation Concentration Degree (PCD), (d) the Precipitation Concentration Period (PCP), and (e) the Rainfall Anomaly Index (RAI), and the non-parametric Mann–Kendall and Sen’s slope tests, for the analysis of trends in the series of precipitation and the studied climate indices. The results obtained indicated that the east of the state presents more distributed precipitation throughout the year, being “moderately seasonal” in the mesoregions Metropolitana do Recife and Zona da Mata; “seasonal” in the Agreste Pernambucano mesoregion; and “strongly seasonal” in the Sertão Pernambucano and Sertão do São Francisco mesoregions. The SPI found that the most severe and extreme droughts occurred in almost all mesoregions during the 1990s, except in the Sertão do São Francisco mesoregion, where they were predominant in the 2010s. Furthermore, based on the RAI index, it was possible to have a greater occurrence of negative anomalies than positive anomalies, especially in the last decade (2010–2020), indicating a possible change in rainfall patterns. However, more in-depth research is required to determine the possible causes of this increased number of negative anomalies. Finally, the trend analysis indicated that only the SPI-12 presented trends in the Metropolitana do Recife, Agreste, and Sertão Pernambucano mesoregions. However, Sen’s slope test indicated that the magnitude of these trends is not significant.

Este trabalho objetiva verificar as tendências de índices de detecção de mudanças climáticas, dependentes da precipitação pluvial diária, nos estados do RN e PB e analisar suas relações com o IVDN e anomalias de TSM nas regiões de Niño 1+2, Niño 3, Atlântico Tropical Norte (ATN) e Atlântico Tropical Sul (ATS). Utilizou-se dados de precipitação de 44 postos, no período de 1935 a 2000, representando todas as microrregiões dos dois Estados; de IVDN, obtidos da NOAA/AVHRR, no período de 1980 a 2000 e de anomalias de TSM, cedidos pela NOAA, de 1950 a 2000. Observou-se uma tendência de aumento das condições de umidade sobre os dois estados. O índice dias consecutivos secos apresentou correlação estatisticamente significativa com as anomalias de TSM das áreas ATN e ATS. Enquanto, os índices dias muito úmidos e quantidade máxima de chuva em cinco dias mostraram correlações significativas com as regiões dos Niño 1+2 e 3 e com a TNA. Em geral, observou-se que o IVDN da Caatinga é mais dependente dos extremos de precipitação do que os da Mata Atlântica. De acordo com os resultados obtidos concluiu-se que as mudanças climáticas detectadas pelos índices são resultantes tanto dos fatores de grande escala como de escala local. Outro resultado obtido foi influência do ENOS sobre os índices extremos de chuva e consequentemente sobre clima e a dinâmica da vegetação do Semi-árido.

Examination of the rainfall data for north‐east (NE) Brazil showed that the drought of 1983 was extensive. In the interior dry region, rainfall during the rainy season of 1983 was less than 40 per cent of the normal. Analysis of the rainfall revealed that the drought of this year was the worst in the past 20 years. Rainfall anomalies over NE Brazil are related to the Southern Oscillation and sea surface temperature (SST) anomalies in the tropical Atlantic Ocean. Variations in the Southern Oscillation index preceded the corresponding rainfall anomalies by about 2 months. Correlation coefficient between the NE Brazil seasonal rainfall and mean monthly SST anomaly in the tropical Atlantic showed a gradual increase from January to March. However, examination of sea surface temperature anomalies in the Atlantic for the first 3 months of 1983 indicated only a weak relationship with rainfall anomalies. This suggests that for the 1983 event east‐west Walker type circulation was more important than the north‐south meridional circulations forced by SST anomalies in the Atlantic.

O principal objetivo deste trabalho é prover novas informações sobre as tendências na precipitação total e eventos extremos de precipitação sobre o Estado do Ceará, fazendo uma análise de diferentes índices de detecção de mudanças climáticas, baseados em dados de precipitação pluvial diária. Utilizaram-se dados de precipitação de 18 postos, no período de 1935 a 2006, representando todas as microrregiões do Estado; o software utilizado no processamento e controle de qualidade dos dados foi o RClimdex 1.9.0. Com base nos resultados encontrados, observou-se que ocorreram mudanças locais na precipitação, assim como um visível aumento nas condições de umidade sobre o Ceará.