The 1980-84 drought in Sudan, Ethiopia and other African countries was caused by a predictable 11-year cycle in sun-spot activity, a prominent American geologist told a news conference last week. Egyptian-born Farouk el-Baz, who was a member of the science support teams for the United States Apollo moon missions, said the worst part of the cycle had now passed.
The Sahel belt on the southern edge of the Sahara could now expect rains for the next seven years, he said.
Baz said policy makers should accept the sun-spot cycle theory instead of blaming the droughts on bad farming and over-population and should avoid ``quick fix'' solutions which often did more harm than good.
``We must learn to live with the cycles -- I believe we can reduce the effects of the droughts by pumping up ground water only during the dry spells,'' he said.
The scientist, who was attending a conference here in Khartoum on sand movements and desertification, said the appearance of sun spots coincided with greater energy transmission by the sun, which in turn produced clouds and rain in the Sahel.
Ancient and modern records of the level of the River Nile provide additional evidence for the theory of an 11-year cycle, he added.
Baz said he had also detected three long-term rain cycles of 200 years, 2,000 years and of many thousands of years but could not yet identify with certainty the mechanisms behind them.
Contrary to popular belief, the Sahara Desert had not always been expanding southwards.
He said that 200,000 years ago it extended 180 miles south of its present lines.
To blame the recent droughts on misuse of the desert by nomads was arrogant and gave rise to the misguided notion that aid agencies and politicians could reverse the trend in the short term, he added.
The geologist said the world was now about 70 years past the rainiest time in the 200-year cycle, so the Sahara would not begin to contract substantially again until after 2015.