Water resources issues in South America

South America has some of the richest water resources in the world. It is second only to Asia in total annual river discharge, but since its land area is less than half that of Asia, it far exceeds all other continents in cubic metres of runoff per square kilometre: almost double that of Asia. Annual water resources in South America average around 582,500 m3 km-2, whilst no other continent yields more than 300,000 m3 km-2. In common with most of the rest of the world, South American water resources face threats from four major trends: population growth, urbanization, climate change and rising water pollution. Climate change is also very much a matter for concern in South America. In general, climate change scenarios produced by the UK HadCM2 model based on increasing levels of greenhouse gases suggest that by the 2080s riverows in South America will exhibit some of the widest variations experienced on any continent, with some substantial regions experiencing over 50% reductions and others with increases of over 50%.