NOAA: Climate Change Did Not Cause Last Year's Megadrought

Last year's epic drought was a freak, a new NOAA report says, and climate change didn't have anything to do with it.

The agency is not entirely sure what did cause it.

But they've basically ruled out human factors.

To recap, the drought was the most wide-reaching in half a century, and created the hottest July ever. One count put its damages as the second-most expensive weather event in history.

And it could not have been predicted, NOAA says.

"The central Great Plains drought during May-August of 2012 resulted mostly from natural variations in weather," the agency says.

Their report continues: "Neither ocean states nor human-induced climate change, factors that can provide long-lead predictability, appeared to play significant roles in causing severe rainfall deficits over the major corn producing regions of central Great Plains," they say.

Instead, there was an unusual drop in moist Gulf of Mexico air, which usually drifts northward this time of year, as well as a lack of large summertime thunderstorms.

Not everyone is buying it.

Meteorologist Jeff Master's of Weather Underground says NOAA basically blew it:

I would have liked to have seen the paper mention the growing body of research that has linked unusually early May snow melt in the Northern Hemisphere and Arctic sea ice loss in recent years to unusual summertime jet stream patterns, like the jet stream pattern observed during 2012. A March 2013 paper by scientists at the Potsdam Institute for Climate Impact Research (PIK) in Germany found that under special conditions, the atmosphere can start to resonate like a bell.

This causes the jet stream pattern to freeze in place and amplify, leading to months-long periods of weather extremes.

They showed that warming of the Arctic due to human-caused climate change might be responsible for this resonance phenomenon, which became twice as common during 2001 - 2012 compared to the previous 22 years.

One of the more extreme examples of this resonance occurred during the summer of 2012, and could have been the cause of the 2012 drought.

Meanwhile, much of the western U.S. continues to suffer through severe drought conditions.