Journal Article

High carbon and biodiversity costs from converting Africa’s wet savannahs to cropland

Licker, Rachel, Thornton, Philip K., Estes, Lyndon, Searchinger, Timothy D., Herrero, Mario, Notenbaert, An, Rubenstein, Daniel, Beringer, Tim, Heimlich, Ralph

2015

Overview

Do the wet savannahs and shrublands of Africa provide a large reserve of potential croplands to produce food staples or bioenergy with low carbon and biodiversity costs? We find that only small percentages of these lands have meaningful potential to be low-carbon sources of maize (∼2%) or soybeans (9.5–11.5%), meaning that their conversion would release at least one-third less carbon per ton of crop than released on average for the production of those crops on existing croplands. Factoring in land-use change, less than 1% is likely to produce cellulosic ethanol that would meet European standards for greenhouse gas reductions. Biodiversity effects of converting these lands are also likely to be significant as bird and mammal richness is comparable to that of the world’s tropical forest regions. Our findings contrast with influential studies that assume these lands provide a large, low-environmental-cost cropland reserve. Africa’s savannahs and shrublands have been assumed to provide a large area for the expansion of cropland with relatively little damage to the environment. Research now shows that conversion would be likely to have high carbon and biodiversity costs.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 704/106/694/682 / Agricultural land / Biodiversity / Carbon sources / Climate Change / Climate Change/Climate Change Impacts / Environment / Environmental Law/Policy/Ecojustice / Ethanol / Greenhouse effect / Greenhouse gases / Land use / Savannahs / Soybeans / Tropical forests / Zea mays