ST. LOUIS (CBS St. Louis/AP) — A new federal study reveals that global warming is not to blame for last year’s extreme drought that crippled the central Great Plains.
The study conducted by the National Oceanic and Atmospheric Drought Task Force places the blame on natural variations in weather patterns that caused the “flash drought.”
The Plains saw very little rain last summer due to two key meteorological processes which NOAA states was a “sequence of unfortunate events.” First, the Plains states saw very little rain in May and June because low pressure systems that brought storms were shunted northward into Canada. Second, thunderstorms were infrequent in July and August and produced little precipitation.
The report states that there were “no strong indicators” a drought of this magnitude would have struck the Midwest last year.
“This is one of those events that comes along once every couple hundreds of years,” lead author Martin Hoerling, a research meteorologist at NOAA, said. “Climate change was not a significant part, if any, of the event.”
Researchers focused on six states – Wyoming, Kansas, Nebraska, Colorado, Missouri and Iowa – but the drought spread much farther and eventually included nearly two-thirds of the Lower 48 states. For the six states, the drought was the worst four-month period for lack of rainfall since records started being kept in 1895, Hoerling said.
Other scientists have linked recent changes in the jet stream to shrinking Arctic sea ice, but Hoerling and study co-author Richard Seager of Columbia University said those global warming connections are not valid.
Hoerling used computer simulations to see if he could replicate the drought using man-made global warming conditions. He couldn’t. So that means it was a random event, he said.
A cool, rainy spring is easing dry conditions in parts of the nation’s farm belt that saw the worst of last year’s drought.
But optimism is being tempered, as that weather pattern has kept anxious farmers in most of Iowa, Nebraska, Illinois, and Wisconsin from planting.
The latest drought monitor released Thursday shows snowmelt and rain replenished ground moisture in parts of eastern Iowa, northern Illinois and southern Wisconsin. Central Iowa counties are improved but still short of moisture.
Rain has helped drought-parched areas of Texas, Oklahoma and Nebraska, but many counties remain woefully dry.
There is enough topsoil moisture in much of the farm belt to allow plants to emerge, but no deep moisture to rely on if the rain stops again.
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