Historical Climatologist Studies Climate Effects

By CnAgri2012-08-27 19:39:37 Print

If producers thought last year's drought was bad, this year's has not proven better. Weather has not been favorable for agricultural production recently, but that might be changing.

At least one climatologist is predicting a break for many Midwest producers suffering from the summer heat and dry weather. Evelyn Browning-Garriss is a historical climatologist who examines historical records, coral growth patterns, tree rings, sediment layers and glacial cores to determine previous climate patterns. She then uses the information those patterns provide to help explain current changing climate patterns and their effect on economic, societal and agricultural trends.

Speaking at the recent 2012 K-State Beef Conference at Kansas State University, Browning-Garriss said she expects La Nina conditions to dissipate, and El Nino conditions to develop within the month of August, bringing welcome relief for many producers throughout the U.S.

El Nino is an oscillating ocean current pattern that tends to shift winds and moisture eastward, bringing cooler temperatures and much needed moisture in from the Pacific. Typically El Ninos are good news for agriculture in the U.S., Brazil and Argentina, while increasing drought risks in other parts of the world, such as northern China, India, Pakistan and northern South America.

She makes predictions such as this based on examinations of 100,000 years worth of yearly weather records found in nature. She searches for a 5-year period exhibiting similar traits to what the world is currently experiencing in terms of natural factors shaping the weather. Then she looks at what follows that 5-year period, saying there is an 80 percent chance of a similar trend developing.

"I'm not making a future projection; I'm giving people perspective," she said.

Browning-Garriss said the world has been experiencing La Nina conditions for the past couple years, combined with a shifting pattern of ocean currents known to climatologists as a Pacific Decadal Oscillation (PDO). A changing PDO tends to magnify the effects of La Nina.

"PDOs make the western U.S. a little drier," she said, "but when you add on a La Nina, you get the kind of drought we saw in Texas."

Historically, a changing PDO tends to reduce production and drive up prices of mid-latitude crops, with little effect on tropical crops. Browning-Garriss said it typically takes a society about 10 years to adjust to the rainfall patterns of a new PDO and for crop prices to stabilize.

With the incoming El Nino, it might be possible to start seeing change sooner though. "I expect when El Nino fully develops, you'll start to see production increase and prices go down," she said.