The Associated Press State & Local Wire July 15, 2006 Saturday Retired scientist's moon theory points to upcoming drought AMES Iowa Louis Thompson says he's learned to keep quiet when Iowa's crops begin to wither. For decades, the retired soil scientist had been forming his moon theory to explain widespread drought every couple decades, but he says critics prefer to use other explanations. "People thought I was a nut, so I quit talking about it," says Thompson, 92. That doesn't mean he abandoned his theory. The statistics, after all, are eerily accurate. Thompson has studied weather and crop records for almost 50 years and his research at Iowa State University pointed him to an 18.6-year cycle of drought and rainy weather that coincides with the moon's path around the Earth. When the moon's orbit is at its northernmost track above the equator as it is now the Corn Belt is due for a drought, Thompson says. 1988 was the last year when severe drought hit, which means the probabilities are mounting that dry weather could hit this year or next. With many areas of Iowa receiving less precipitation this year, Thompson is quietly pointing to his theory. S. Elwynn Taylor, an Iowa State University Extension climatologist, says Thompson is known around the world for his 18-to 19-year crop cycle. He says the correlation of the moon's orbit and rainfall lacks scientific proof but at least has historical support. Tree ring records going back 800 years in parts of the United States show the cycle has been amazingly consistent, Taylor says. Thompson's resume indicates he knows what he's talking about. He was educated as a soil scientist at Texas A&M and Iowa State University, where he received a doctorate in 1950 in soil fertility. Thompson taught agronomy at Iowa State, was the professor in charge of farm operations for seven years and served as an associate dean in the agriculture college. He retired in 1983. In 1960, Thompson developed an interest in climatology while he served in the U.S. Army Reserve. "I proposed that I could develop a method to predict crop yields from weather data," Thompson says. "I was told it couldn't be done, but I did it in a year." Digging into records going back to 1810, he found there was an 18-to 19-year cycle between drought years. That lined up with the moon's orbit cycle, Thompson says. Decades of the 1930s, 1950s and 1970s were mostly dry, Thompson says. The 1920s, 1940s and 1960s were generally wetter. Thompson has spoken about other weather phenomena over the years, including the impact of the warming or cooling of the eastern Pacific Ocean known as El Nino-La Nina. Those forces trump the moon's impact on climate and drought, Thompson says, and that's why a drought may not happen this year. Taylor says that after months of neutral signals, the scale is tipping toward El Nino conditions, which generally produce better crops in the Corn Belt. "That's nothing but good news for us," Taylor says. "It means it won't be oppressively hot." If this El Nino develops and trumps the moon cycle, as Thompson says it might, there's always next year.