Seven-year cycles

The CS Monitor reports:

When archaeologists sift through the debris of a vanished culture, they should consider the ancient climate. It can shed light on the bygone habitat and give plausibility to old myths. It can also give a useful perspective on our own climatically uncertain times.
Take the biblical tale of Joseph. The famous seven-year cycle of feast and famine appears to be one of Egypt's regular routines, according to Dmitri Kondrashov, Yizhak Feliks, and Michael Ghil at the University of California at Los Angeles.
The scientists used new statistical techniques to fill in gaps in 1,300 years of Nile River water levels recorded from AD 622 through 1922. They then searched these data for climatically significant cycles. Their results, reported in Geophysical Research Letters, suggest "quite strongly" that North Atlantic circulation influences East African climate. The scientists add that "most strikingly," their analysis picked out a North Atlantic driven seven-year cycle of high and low river levels that is "possibly related to the biblical cycle of lean and fat years."

Of-course if this were proven true, it would in a sense undermine the Joseph story as his prediction of the lean/fat years wouldn't be as remarkable if it were part of a regular cycle.