Climate Change and Water Resources

Abstract

This report presents a general vision of the availability of water in Brazil within the context of climate variability and change. Despite Brazil having great water availability, its distribution among the regions is very uneven. The current situation, in terms of scarcity, is mainly due to inadequate planning of land and water use associated to economic growth: as an example, the Southeast area of Brazil, which has great water availability, is affected by lack of water due to uncontrolled urbanization growth. Water availability in Brazil is directly related to the climate, especially during the months of summer. Delays in the start of rainy seasons can affect agriculture and the hydroelectric power generation; and the occurrence of severe floods and droughts have caused great impacts in the economy and to the population. This can be seen, for example, in the case of the drought in Amazonia in 2005 and the floods of 2009 in Amazonia. Brazil is vulnerable to these climatic anomalies and will be vulnerable to the changes projected on rainfall patterns and on extremes weather patterns due to climatic change. Changes in patterns and in precipitation regimes could also affect river flows; current studies indicate that the most affected river will be the Sao Francisco River, where the reduction in rainfall will result in a drastic decrease of discharge and consequently will severely impact irrigation and the hydroelectric power generation. Without a doubt, the uncertainties of the future projected scenarios always need to be taken into consideration. Actions focused on adaptation and mitigation is urgent, as are monitoring plans for water resources in order to assess climatic risks. Comprehensive research on climatic change and its impacts on water resources is extremely necessary. Water resources management should also consider the climate change projections and uncertainties in the implementation of water policies and regulations.