The floods in Swat and the Indus valley are, like the yellow fever mosquitoes of the Netherlands, an indication that things could get worse.

Arid lands, surprisingly, contain some of the world's largest river systems, such as the Murray-Darling in Australia, the Rio Grande in North America, the Indus in Asia, and the Nile in Africa.

Those cattle are both assets and income generators for Pakistani villagers along the Indus River.