Vulnerabilities of water security faced with climate change in Brazil

Abstract

This study presents the analysis of impacts and vulnerabilities in the face of climate change in water security in Brazil. The analysis is based on Impact, Vulnerability and Adaptation (IVA) climate change studies component of the Fourth National Communication (4CN) of Brazil to the Convention on Climate. We analyzed water security vulnerabilities from the dimensions of availability, accessibility, security, and governance. The future climate scenarios indicate an amplification of current impacts and vulnerabilities. The reduction in water availability in the Caatinga, Cerrado, and Atlantic Forest biomes, where territories are marked by high population concentration and multiple water uses, shows the fragility in the relationship between water supply and demand in different warming scenarios. All biomes, especially the Amazon, Atlantic Forest, and Caatinga, present vulnerability to floods and low water quality in metropolitan regions. Low rates of accessibility to drinking water and sanitary sewage are also important vulnerabilities. The water and sewage services universalization at the municipal level is an urgent public health matter and is considered an action independent of climate change scenarios uncertainties. The lack of water quality information in regions farther from urban centers, especially in the Amazon, Caatinga, and Cerrado biomes, complicates the diagnosis of diffuse pollution hotspots in areas with significant agricultural crops. The Brazilian legislation is progressive and emphasizes the decentralization of water management. However, the lack of basic instruments such as the state and river basin water resources plans is a barrier for water law guarantee, especially in the Amazon. Institutional capacity was fragile and limited according to its proximity to larger urban centers. The effectiveness of governance evaluation as well as the gaps and opportunities diagnosis in the face of extreme events are relevant contributions to avoid water crises and recurrent floods. The universalization of water and sewage services and the increase of institutional capacity are relevant topics. Furthermore, a monitoring system expansion for a more accurate diagnosis at the municipal scale – especially indicators of biodiversity, water quality, diffuse pollution, and consumption by sector – is also pertinent to improve the water security in the country.