Pacific predictions What's a reliable way to predict the size of maize harvests in southern Africa—and about a year in advance? Pacific Ocean temperatures, according to Earth scientists at Columbia University's Lamont-Doherty Earth Observatory. In the July 21 issue of Nature, the Earth science researchers report an “astonishing” link between the periodic shifts of tropical Pacific surface water temperatures known as El Niño/Southern Oscillations (ENSO) and Zimbabwe's maize crop yield. In the future, forecasts based on the ENSO can provide early warning of pending dangerous fluctuations in southern Africa's harvests, where maize yields have varied from 2.4 tons per hectare in 1986 to 0.4 tons in 1992. To be sure, lead authors Mark A. Cane and Gidon Eshel say, the ENSO cycle will continue, and there will times of drought in southern Africa. Predictions for next year should be available in September. What's more, Cane says, the model may be used to predict crop yields in other parts of the world, as “ENSO directly affects the climate of more than half the planet.”