US weather whiplash shows climate change

A series of "once-in-a-millennium" rainstorms have lashed the United States in recent weeks, flooding areas baked dry by long-term droughts, as human-caused climate change brings weather whiplash.

And scientists warn that global warming means once-rare events are already much more likely, upending the models they have long used to predict possible disasters, with worse to come.

At least 40 people have been killed in the last month by storms in Kentucky, Illinois, Texas and Missouri, inundating areas that in some cases had seen little to no rain for months.

Up to 12 inches (30 centimeters) fell in one of these storms, the kind of downpour that statistical models say should only happen once in a thousand years.

"This is 'weather whiplash,'" tweeted Peter Gleick, co-founder of the Pacific Institute, a non-governmental organization that works on water issues around the world.

It is "caused by an intensification of the global hydrological cycle & how it distributes water around the planet, influenced by human-caused climate change."

The warnings scientists have been sounding for decades about the effects of unchecked fossil fuel use are suddenly coming into focus for millions of people.

A warming planet is not a benign place in a far-off future where it is always a bit sunnier; it's a place of wild swings, where the wets are wetter and the dries are drier. And it's now.

"The commonality between these and other extreme rainfall events is you need just the right set of ingredients to come together," said David Novak, director of the Weather Prediction Center at the National Weather Service.

"You need moisture, you need instability in the atmosphere. And you need some sort of... feature to kind of ignite the...