A severe lack of rain is drying up rivers and water supplies needed to produce clean energy in several countries. In some cases, governments are depending more on fuels that can pollute the environment. Countries, including the United States, China and Brazil, are beginning to have problems with producing hydropower from hydroelectric dams. Scientists and energy experts say these problems are likely to continue as climate change causes more unpredictable weather. Lack of rain, or drought, could also threaten international efforts to fight global warming. The International Energy Agency says that hydropower is the world's top way to produce clean energy. Nearly 16 percent of the world’s electricity comes from hydroelectric dams. This year, droughts have caused problems for hydropower generators in the western United States and Brazil. China is still recovering from the effects of last year's drought in Yunnan province on its hydropower production. Those effects have forced power suppliers to depend on natural gas or coal fueled power. They are also asking businesses to cut their electricity use to prevent outages.
