Climate Feedback: Flash floods – a sign of what’s in store?

Olive Heffernan, writing at Climate Feedback is writing on the increasing incidence of flooding being seen around the world:

“Calling it a ‘21st century catastrophe’, Michael McCarthy at the Independent writes that ‘Britain is suffering from a wholly new type of civil emergency: a disaster caused by 21st-century weather,’ which has left more than a third of a million people without drinking water, nearly 50,000 people without power, thousands more people homeless and caused more than £2bn worth of damage so far.

Britain is not alone in experiencing extremely heavy rainfall. As reported on MSNBC, ‘parts of China had the heaviest rainfall since records began, killing more than 700 so far this year. Hundreds of thousands have been displaced by flash floods in southern Pakistan.’

While these single events cannot be attributed to climate change, many are questioning if the flash flooding is a sign of what is in store for the future. And scientists have some of the answers.

In a paper coming out in Nature this Thursday, Francis Zwiers of the Canadian Centre for Climate Modelling and Analysis in Toronto and colleagues present the first evidence that human-generated greenhouse gas emissions have altered rainfall patterns in the 20th Century. In the region between 40 and 70 degrees North, covering northern Europe, Russia and parts of North America, rainfall increased by 62 millimetres per century between 1925 and 1999. Zwiers and colleagues say that 50-85% of this increase can be attributed to human activity. For further discussion and comments on the paper, there’s a news story by my colleague Daniel Cressy on News@Nature. And it’s also been picked up by the BBC.

And a recent paper published in Science in June suggests that global warming may result in even more rainfall worldwide than is currently evident in climate model simulations. Frank J. Wentz of Remote Sensing Systems in Santa Rosa, California and co-workers compared global satellite data from 1987 to 2006 and found that rainfall increased at the same rate as atmospheric water vapour per degree Celsius of surface warming. Climate models had projected a dampened response of rainfall to global warming owing to a decrease in surface winds, but Wentz and colleagues found that surface winds have in fact become stronger, leading to heavier rainfall (more on this in Nature Reports Climate Change soon).”

What the paper does not mention, but which others have, is that the effects these changes seem to be the most disruptive in the developing world – and represent a real crisis that may block their movement toward being fully sustainable economies.

Read the rest here: Flash floods – a sign of what’s in store?

(Via Climate Feedback.)

Author: Nick Knisely

Episcopal bishop, dad, astronomer, erstwhile dancer...