12. Tropical hydropower dams as greenhouse sources
Large tropical hydropower reservoirs in Latin America may have a potential adverse impact on the climatic system through releasing greenhouse gases into the atmosphere. Submerging large areas of land and tropical vegetation under water and fluctuations in water level promote physical-chemical processes that decompose the organic matter and generate methane and carbon dioxide emissions. In the initial years of operation, emission levels are especially high. In the case Tucuru and Balbina dams in the Amazon, potential emissions of greenhouse gases could be much higher than a natural gas combined-cycle plant of similar capacity.