Warming, other factors worsened Pakistan floods, study finds

Climate change likely juiced rainfall by up to 50% late last month in two southern Pakistan provinces, but global warming wasn’t the biggest cause of the country’s catastrophic flooding that has killed more than 1,500 people, a new scientific analysis finds.

Pakistan’s overall vulnerability, including people living in harm’s way, is the chief factor in the disaster that at one point submerged one-third of the country under water, but human-caused “climate change also plays a really important role here,” said study senior author Friederike Otto, a climate scientist at Imperial College of London.

There are many ingredients to the still ongoing humanitarian crisis — some meteorological, some economic, some societal, some historic and construction oriented. Add to that weather records that don’t go back far enough in time.

With such complications and limitations, the team of international scientists looking at the disaster couldn’t quantify how much climate change had increased the likelihood and frequency of the flooding, said authors of the study. It was released Thursday but not yet peer reviewed.

What happened “would have been a disastrously high rainfall event without climate change, but it’s worse because of climate change,” Otto said. “And especially in this highly vulnerable region, small changes matter a lot.”

But other human factors that put people in harm's way and weren't adequate to control the water were even bigger influences.

“This disaster was the result of vulnerability that was constructed over many, many years,” said study team member Ayesha Siddiqi of the University of Cambridge.

August rainfall in the Sindh and Balochistan provinces -- together nearly the size of Spain -- was eight and nearly seven times normal amounts, while the country as a whole...