Exploiting El Nino to Avert African Famines

Article excerpt

Like all farmers, maize growers in Zimbabwe must read the sky before planting. But instead of looking directly above their heads, southern African farmers should focus on weather in the Pacific Ocean, clear on the other side of the globe, according to the results of a new study

A team of US. and Zimbabwean researchers detected a strong correlation between temperatures in the Pacific and maize growth in Zimbabwe since 1970. When the Pacific cooled, Zimbabwe received plentiful rains and farmers there reaped large maize harvests. When so-called El Nino warmings brewed in the tropical Pacific, maize crops in Zimbabwe suffered, report Mark A. Cane of the Lamont-Doherty Earth Observatory in Palisades, N.Y., and his colleagues.

The link can have disastrous consequences. During the 1991-1992 El Nino, southern Africa weathered its worst drought this century and cereal harvests throughout the region fell by half.

But the Pacific connection also offers potential benefits, because Cane and other atmospheric scientists are learning how to predict the arrival of El Ninos more than a year in advance. By taking advantage of forecasts for the Pacific, farmers in Zimbabwe could try to predict the coming harvests before actually planting, Cane's group writes in the July 21 Nature. If forecasts call for poor rains, maize growers can use drought-resistant varieties and governments can build up regional grain stocks.

"If we can tell in September, before the rains start, what the whole season will be like, this would be an enormous advance," says coauthor Roger W. …