The IPCC assessment reports note that higher ocean temperatures lead to more water vapor entering the atmosphere. This fact, Asrar said, already pointed toward a stronger than usual monsoon season in store for South Asia.
Abnormal airflow dumps supersaturated air
Normal air patterns would have dispersed this precipitation over as wide an area as possible. But an abnormal airflow caused by La Niña created a ridge of pressure that blocked the warm, saturated air from moving west to east normally, Arar said.
This same ridge prevented the rains from reaching western Russia, where a severe drought has been blamed for raging wildfires and the destruction of 20 percent of the wheat crop there. And with nowhere else to go, Pakistan and China's far west bore the brunt when the clouds became too saturated with moisture and opened up.
"Basically, this rift that was forming blocked the warm air moving from west to east, and then, on the other side, this air that was super saturated with water vapor had to precipitate all this excess water that was in the atmosphere, which created this unprecedented amount of rain in short period of time," Asrar explained. "The connecting factor is that clearly the warming is a driver for all these events."
The United Nations says that $459 million is need for international and nongovernmental relief agencies to respond to the disaster. About 35 percent of that appeal is now funded, mostly by contributions from the U.S. and U.K. governments.
Donations from other corners and the private sector have been slow in coming, though aid officials are reporting an uptick in contributions in recent days.
"The response has been a bit slower than perhaps with other disasters but definitely donations are starting to come now," said Airlie Taylor at the London offices of ActionAid International. "I think the world is now starting to wake up to the magnitude of the crisis."
The International Federation of Red Cross and Red Crescent Societies (IFRC) is asking for $16 million in donations to buffer the emergency relief activities of the Pakistan Red Crescent Society.
Though more rain is expected and the southern reaches of the country can expect further flooding as the rivers drain out, rumors that India might release even more water from dams upstream are causing a panic in some areas. Pakistani authorities say the rumors are baseless and are desperately trying to get the word out to prevent a spread of disorder.
"The data collected about the Indian dams on Ravi, Sutlej and Beaus Rivers indicate that these dams are not yet filled to their capacity and further no flood producing strong monsoon rainy system is in sight," said Qamar-uz-Zaman Chaudry, head of the Pakistan Meteorological Department, in a release. "As such we may not expect that India would release sudden flood water in these rivers in the next five to ten days at least."
Hundreds of thousands of homes lost
Hundreds of thousands of homes have been completely swept away all over the country, and several communities have been cut off from the outside world as floodwaters washed bridges and roads away. Officials don't yet know what the full cost of recovery will be, but all expect it to be tremendous -- Akram in Geneva told reporters that the cost to rebuild Khyber-Pakhtunkhwa province, one of the hardest hit, would be at least $2.5 billion.
"The needs on the ground require a massive response," said IFRC chief Bekele Geleta. "It's not just about saving people's lives today; we need to plan for their long-term recovery tomorrow."
The litany of weather incidents during the summer of 2010 reads like the latest Hollywood global disaster movie.
The hottest summer ever recorded in 130 years has sparked thousands of wildfires in Russia, burning some entire villages to the ground, killing 53 and leaving 3,500 homeless, according to Russian state media. Cooler temperatures are finally bringing some relief, shrinking the extent of the flames from more than 100,000 acres down to about 54,000 acres.