ROBERT SIEGEL, HOST:
It's been just a couple of months since we emerged from the latest El Nino, the ocean-warming trend that crops up in the Pacific every few years and changes weather patterns across the globe. Well, now scientists are keeping watch for the possible start of El Nino's frequent counterpart La Nina, an ocean-cooling trend that tends to produce the opposite effects. NPR's Nurith Aizenman reports the consequences could be especially important in southern Africa.
NURITH AIZENMAN, BYLINE: To appreciate why people in southern Africa are on edge right now, you need to know just how hard this past El Nino hit the region. El Nino always tends to bring dry spells to that part of the world, but the effects of this one, which ran from May 2015 through this past spring, were off the charts.
CHRIS NIKOI: This El-Nino-induced drought is the worst in 35 years in southern Africa.
AIZENMAN: Chris Nikoi is with the United Nations' World Food Programme. He notes that farmers in southern Africa - countries like Malawi, Mozambique, Zimbabwe - typically do their planting in October, when the annual rains began. But this past October...
NIKOI: The rains did not come.
AIZENMAN: Many people waited, hoping the rains would pick up in November or December or January. They didn't.
NIKOI: Some eventually - they just took a chance and planted, but all the crops wilted.
AIZENMAN: By this spring...
NIKOI: For many households, they basically had next to nothing to harvest.
AIZENMAN: This is particularly problematic because in southern Africa, there's only one harvest season. Nikoi says for people whose only source of food is what they grow - and that's the majority of people there...
NIKOI: You need to get a good harvest, so basically you've got to harvest enough to cover your needs for 12 months.
AIZENMAN: Already, hundreds of thousands of people are starting to run short of food. By next March, that number is projected to reach 18 million. And officials say they need to start getting food aid into place now, largely because of La Nina.
LISA GODDARD: So El Nino and La Nina are, in simple terms, like, flip side of the coin.
AIZENMAN: Lisa Goddard heads Columbia University's International Research Institute for Climate and Society.
GODDARD: You know, roughly, if you sort of squinted your eyes at a map, they look kind of opposite.
AIZENMAN: So if a La Nina develops - and most El Ninos are followed by La Ninas - in Southern Africa, the rainy season that's set to start again in October could be extra wet. And that's going to make it hard to get food into the places where people are going hungry. Here's Nikoi again.
NIKOI: Many are areas with very poor road infrastructure, so as soon as the rains start, these roads will become impassible by trucks.
AIZENMAN: But there's another reason for urgency that's more positive. See, all that extra rain from La Nina could produce the best harvest in years. The trouble is right now farmers don't have the seeds to take advantage of the opportunity. Shukri Ahmed is with the U.N.'s Food and Agriculture Organization.
SHUKRI AHMED: Many of the farmers either sold what they have left, in terms of seeds, or they ate it.
AIZENMAN: Ate their seeds because we're talking about maize kernels, which, in a pinch, will fill your belly. So the U.N. is also now racing to get seeds to the farmers. In short, thanks to La Nina, things could turn around for southern Africa, but, says Ahmed, we have a narrow window to make that happen. Narith Aizenman, NPR News. Transcript provided by NPR, Copyright NPR.