An African Region Beats Back the Desert, Thanks to Trees
The Sahel region in Northern Africa is sandwiched between the Sahara desert in the north and the savanna in the south, stretching across nearly a dozen countries. It is a hot, dry region where it’s hard to grow most crops, so locals depend on subsistence livestock herds, mostly cattle, sheep, and goats.
Overgrazing has long been blamed for creeping desertification of the Sahel, especially in the wake of devastating droughts in the 1970s and '80s.
Now, research from South Dakota State University blows both claims out of the water, showing that 84 percent of the watersheds in the Sahel have recovered.
“In the past people have had a negative perception of the Sahel, that the pastoralists are misusing and overgrazing the land, but these findings prove that’s not true,” said Niall Hanan, a savanna ecologist with SDSU who has focused on Africa for the past 25 years.
The researchers found that the Sahel region has bounced back from the epic droughts of decades past. Despite a mix of wet and dry years since then, the region has grown green as rainfall has increased. While grasslands have recovered, trees have made an even bigger comeback.
“Trees are the main change we’ve seen over the last 30 years,” he said. “In northern Senegal, for example, tree populations have doubled.”
The research underscores the key role trees play in fighting drought and climate change and influencing weather patterns.
Researchers tracked the recovery using NASA's and the National Oceanic and Atmospheric Administration’s satellite images.
That’s a rare bit of good news in the face of growing evidence of climate change’s impact on Africa. The parts of the Sahel region the scientists studied—Senegal, Mali, Niger, and Burkina Faso—have proved resilient.
“We think people were too pessimistic in talking about desertification and degradation in the '80s and '90s, and many in the general public still hold that opinion,” he said. “There’s no downward creeping of the Sahara, I can confidently say that.”
Niall emphasized, however, that the study was not about climate change and should not be misconstrued.
“If climate gets drier and hotter in the region, the livelihoods of the pastoralists will be in jeopardy,” he said. “But our findings indicate that their lifestyle and pattern of land use are well adapted to the area.”