Pakistan floods shows threat from warmer world: Scientists

Floods that have devastated Pakistan could be a sign of the future as climate change brings greater extremes of weather to the region.

While climate scientists say single flooding events can't be directly blamed on global warming, more intense droughts and floods could be in the forecast for the future.

And for Pakistan's 160 million people, many already facing regular droughts and floods, that could cost more lives and threaten cotton, wheat and rice crops and infrastructure.

It could also add to the security challenges in what is already one of the world's poorest and volatile nations that is battling Islamic militancy. The government has been heavily criticised over its poor response to the crisis.

Scientists say Pakistan could also suffer in the long-term from declining amounts of meltwater from glaciers feeding the Indus River, which is nation's life-blood.

For the current floods, rainfall of about 400 millimetres (16 inches) in mountainous areas in the far north of Pakistan and adjoining parts of Afghanistan between July 28 and 29 triggered a torrent of water down the Indus and Kabul Rivers.

"That was a record," said Qamar-uz-Zaman Chaudhry, director-general of the Pakistan Meteorological Department.

"The only explanation can be the link to climate change. Because that area very rarely receives monsoon rains," he told Reuters, pointing to the risk of the monsoon belt shifting as well as changes in the intensity of the monsoon.

He said the current floods could also be blamed to some degree on deforestation and more people living in flood-prone areas as the population keeps growing.

Pakistan has lost vast areas of forest over the past few decades, while overgrazing often strips degraded land of whatever plant cover is left. The government has set a target to boost forest cover from 5.2% to 6% by 2014. 

Climate scientists say it is much easier to link climate change and heatwaves such as the one that has triggered wildfires and wiped out wheat crops in Russia.

"Floods are harder to pin down," said leading Australian climate scientist Neville Nicholls.

"We expect changes in precipitation but the science to actually to attribute those to global warming hasn't been done yet," Nicholls, of Monash University in Melbourne, said.

He also pointed to the global climate moving from an El Nino to a La Nina, a natural swing in sea surface temperatures in the Pacific Ocean that can trigger drought in Australia and Southeast Asia and then floods, as well affecting South Asia monsoon.

"In parts of the world, that sequence does lead to really quite strange, anomalous rainfall," he said.

Indian experts point to evidence of rising temperatures in the Himalayas and more intense rainfall events.

"No one can say for sure that this is all related to climate change, but yes there is circumstantial evidence that over (the last) 20 years very heavy rainfall events have drastically increased," Bishwajit Mukhopadhyay, deputy director-general of meteorology at the India Meteorological Department, told Reuters.

Scientists say nations will need to start adapting to climate change impacts such as more intensive droughts and floods but poorer nations with limited cash face the toughest challenge.

Pakistan, like any flood-prone country, needed early warning systems, better storage of drinking water, even to move people from vulnerable areas, said Andrew Ash, who leads a climate adaption programme for Australia's state-funded research body the CSIRO.

"There are definite limits to adaptation. We often talk about adaptation as if we can adapt our way out of trouble," he told Reuters. "But these sorts of events highlight that we can't adapt our way out of all the impacts of climate change." 

Pakistani food expert Abid Suleri, executive director of the Sustainable Development Policy Institute, said the country would need to work on seed varieties to adapt to climate change.