Cropping Africa's wet savannas would bring high environmental costs

A press release from Princeton University (the Woodrow Wilson School): With the global population rising, analysts and policymakers have targeted Africa's vast wet savannas as a place to produce staple foods and bioenergy groups at low environmental costs. But a new report published in the journal Nature Climate Change finds that converting Africa's wet savannas into farmland would come at a high environmental cost and, in some cases, fail to meet existing standards for renewable fuels.

Led by researchers from Princeton University's Woodrow Wilson School of Public and International
Affairs and Department of Ecology and Evolutionary Biology, the study finds that only a small percentage of Africa's wet savannas (2-11 percent) have the potential to produce staple crops while emitting significantly less carbon dioxide than the world’s average cropland. In addition, taking land conversion into account, less than 1 percent of these lands would produce biofuels that meet European standards for greenhouse-gas reductions.

"Many papers and policymakers have simply assumed that Africa's wetter savannas are expendable from an environmental standpoint because they aren’t forests,” said co-lead author Tim Searchinger, a research scholar at Princeton's Program in Science, Technology and Environmental Policy (STEP), which is based at the Woodrow Wilson School. "Governments have used this assumption to justify large leases of such lands to produce food for the outside world and large global targets for bioenergy. But when you actually analyze the realistic potential to produce food or bioenergy relative to the losses of carbon and animal biodiversity, the lands turn out not to be low cost."

Even if these lands are converted for agricultural use, the only way Africa could become an exporter of crops is by depriving its own people of food, the researchers report. Farming a large expansion of Africa's savannas — nearly half of the world's remaining savannas — would also have negative impacts on the rich and diverse population of tropical birds and mammals....

On the Cameroon savanna, shot by Amcaja, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license