It is generally acknowledged that the world’s water problems continue to worsen, but the deterioration is not always directly linked to anthropogenic factors. Lake Chad has shrunk to one twentieth of its size 40 years ago, but this may have more to do with persistent drought than with direct human impact. The causes of other threats are more obvious. Since 1950, the number of large dams worldwide has increased from about 5,000 to roughly 45,000, with a proportionate increase in the degree of ecosystem alteration and destruction. In South America, the projected multinational Hidrovia Dam will (if it goes ahead) turn the Paraná and Paraguay Rivers into a barge canal that will drain the Pantanal – one of the world’s largest and most biodiverse wetlands.