Pakistan, Oct. 5 -- Some fifty million years ago tectonic plates crashed and the Himalayas were pushed upwards. The seabed transformed into still rising mountains. Ocean currents started circulating anew, and wind patterns changed. Warming waters caused increased moisture evaporation, with it precipitation of rain and snow. Glaciers formed. The Indus River System was born. The geography and climate of the subcontinent started evolving into the form we see today. This was about ten million years ago.

Monsoons and the resulting flooding are an ancient phenomenon. Over millennia, climate systems have adjusted slowly, but a few times the change has been sudden, and catastrophic. Change is the only constant. Our geologic era is called the Ant...