The flooding witnessed in the Indus Valley is unprecedented in the country’s modern history and was caused by a combination of increasingly warm ocean water and a mysterious blockage of the jet stream, which drew warm, water-laden air north to Pakistan, over which it burst in sheets of raging liquid. If the floods that followed prove a harbinger of things to come, then they are a milestone in our experience of global warming, a big story in its own right.
This is the story as reported by Professor Juan Cole in his excellent article for anybody outside Pakistan:
The Great Pakistani Deluge Never Happened: Don’t Tune In, It’s Not Important
There you have the entire article, on Guernicamag.com. Juan Cole's writings can be read at Informed Comment.