The team, led by Charles Vorosmarty of the City College of New York, used a composite index of water threats to both humans and biodiversity, such as scarcity and pollution, in 2,500-square-kilometre squares over the world’s surface. ‘What we’ve done is to take a very dispassionate look at the facts on the ground – what is going on with respect to humanity’s water security and what the infrastructure that has been thrown as this problem does to the natural world,’ Vorosmarty said.

They found that some of the world’s most threatened rivers are in the developed world, including examples in the USA and western Europe, despite decades of attention to pollution control and investments in environmental protection. Rivers were at least risk in areas where human populations are smallest, such as in the Arctic and in relatively inaccessible parts of the tropics.

According to the researchers, conserving water in dams and reservoirs helps to provide security for people, but often damages biodiversity. Instead, governments should combine infrastructure with efforts to safeguard natural resources such as watersheds, wetlands and floodplains.   

December 2010