Author(s)

M. A. V. Freitas & J. L. S. Soito

Abstract

Brazil has the largest reserve of surface water on the planet, approximately 19.4%, of the world total, and one of the greatest hydraulic potentials. This does not however mean that it is in a comfortable position in terms of water availability and the location of consumptive and non-consumptive demand. In fact, around 90% of the water is to be found in the low demographic density hydrographic basins of the Amazonas and Tocantins rivers. Around 90% of the population relies on the remaining water resources. Given the major role of hydroelectric plants in the Brazilian Electricity System, power generation in the country is highly dependent on the hydrologic regimes of the hydrographic basins. Given that there is regional imbalance in water availability – as evidenced by recurrent droughts in the North-eastern region and by the degradation of rivers and soil in the South East, the socioenvironmental risks to each region and the rapid increase in the demand for water and energy throughout country – new and existing hydroelectric energy plants are vulnerable, to a lesser or greater extent, to climate change. The risk of future global climate change i.e. further warming of the planet, may alter the hydrologic cycle, and, consequently, the regime and hydric availability of the hydrologic cycle. In fact, differentiated changes in temperature lead to alterations in the range of atmospheric pressure and wind patterns. Changes in rainfall pattern are therefore to be expected. The forecast rise in sea levels by 2099 indicates, in various scenarios of greenhouse gas emission, a range of between 18 cm and 59 cm. The occurrence of the El Niño Southern Oscillation (ENSO) has been more frequent, longer and

Keywords

vulnerability, climate change, water management, hydropower, generation