Africa's Sahel has seen drought and downpours intensify, but scientists don't know whether the long-term trend is drier or wetter. Pictured: Koungheul, Kaffrine, Senegal. Image: Flickr/Senegal - Agosto de 2009
DAKAR, Senegal – Just two seasons exist here: the rainy and the dry. At the best of times, the temperamental rains come for three or four months and turn dusty plains into green pastures, forests and fields.
But in the late 1960s, the rains came later and ended earlier. A drought started. Crops failed across the region; freshwater rivers turned to saltwater.
In the Sahel, a semi-arid belt across West Africa south of the Sahara Desert, at least 100,000 people perished and millions of cattle died for want of pasture. That was just in the beginning. The drought persisted – for five years, then 10, then 20.
The severity provoked a humanitarian catastrophe. It was the crisis of a generation, yet scientists did not understand why it was happening.
In the 1980s, with the drought still ongoing, Gregory Jenkins was studying atmospheric science as a graduate student at the University of Michigan. After finishing his doctorate, he moved to Boulder, Colo., for a fellowship with the National Center for Atmospheric Research. He focused on West Africa – in part because of the prolonged drought's ravaging impact. But he also saw a chance to develop a niche in a region where few other climate scientists were active.
"These changes were big. They caused hardship on tens of millions of people. Not for one year, but for decades. And we didn't see anything like that around the globe," said Jenkins.
Today Jenkins is an associate professor at Howard University and a climate modeler, a profession not particularly known for its field opportunities. But early on Jenkins realized that the global climate models are too coarse to tell much about what's going to happen in the Sahelian zone.
He had to get to Senegal.
The drought ended in the 1990s. Life in the Sahel hasn't been the same since. Pastoralists couldn't afford to rebuild their herds. Farmers abandoned their fields. Rural areas emptied, with once-thriving regional centers transformed into ghost towns that have never been able to bounce back. The ensuing urban explosion had its own consequences, too – in poverty and crime and even the pressure to leave the continent and go abroad, with papers or without.
Scientists now believe that the Sahelian drought was an indication of climate change. They expect climate change to do a number on this ecosystem, causing droughts and floods, disasters upon disasters. Prevention might not be possible, but if the world knows what's coming, local governments could at least prepare.
In 1993 Jenkins packed some instruments and headed to Dakar. In the two decades since, he has returned every year, traveling the countryside, visiting with friends, installing rain gauges, stopping for a bowl of ceebujen, the national dish of fish and rice. He'll sit with Senegalese colleagues on their ateliers and help their students analyze data. Sometimes he brings his students from Howard University. It's important, he says, to expose young Americans to important science and societal issues abroad.
Senegal has been a good base, too, with consistent political stability over the last 20 years. Every country that it shares a land border with has had a coup d'etat or two or even three since then.
In Africa, weather systems develop from east to west, but continuous data are rare. Security problems and war plague parts of the region. Funds are scarce. "We have no data from Sudan, not much from Chad, and we know the weather systems are developing and going past those areas. And when bad things happen in Mali, we know we lose observations," he said. Satellite data can help, he added, but it is sometimes too coarse to be meaningful.
This gap hampers scientists' ability to understand what the future holds for this part of the world. Scientists don't know if West Africa will be wetter or drier. And that has huge policy and humanitarian implications.