COS 110-2 - Deforestation risk due to commodity crop expansion in sub-Saharan Africa

Wednesday, August 9, 2017: 1:50 PM
D133-134, Oregon Convention Center
Elsa M. Ordway, Earth System Science, Stanford University, Stanford, CA, Gregory P. Asner, Department of Global Ecology, Carnegie Institution for Science, Stanford, CA and Eric F. Lambin, Woods Institute for the Environment, Stanford University, Stanford, CA

Rapid integration of global agricultural markets and subsequent cropland displacement in recent decades has increased large-scale tropical deforestation in South America and Southeast Asia. Growing land scarcity and more stringent land use regulations in these regions could incentivize the offshoring of export-oriented commodity crops to sub-Saharan Africa (SSA), which harbors 25% of tropical forest biomass carbon stocks and thousands of endemic species. We: (i) determined whether export-oriented agricultural expansion is increasing more rapidly in SSA compared to domestic crops and previous years, and the contribution of SSA to expansion of these crops throughout the tropics; (ii) identified countries in SSA at risk of agricultural expansion in tropical forests; and (iii) evaluated whether deforestation is associated with industrial, large-scale monoculture expansion. Commodity crop expansion trends were analyzed at the regional scale. Risk of agricultural expansion in tropical forests was evaluated at the country-level using a disaster management framework, where risk is a function of exposure, vulnerability, and pressure. We conducted a remote sensing analysis of land-use change across Southwest Cameroon, a major crop-producing region in the Congo Basin, to analyze the association between deforestation and industrial monoculture expansion.


We found that commodity crops are expanding in SSA, increasing pressure on tropical forests. Four Congo Basin countries, Sierra Leone, Liberia, and Cote d’Ivoire were most at risk in terms of exposure, vulnerability and pressures from agricultural expansion. These countries averaged the highest percent forest cover (58% ±17.93) and lowest proportions of potentially available cropland outside forest areas (1% ±0.89). Foreign investment in these countries was concentrated in oil palm production (81%), with a median investment area of 41,582 thousand ha. Cocoa, the fastest expanding export-oriented crop across SSA, accounted for 57% of global expansion in 2000-2013 at a rate of 132 thousand ha yr-1. However, cocoa only amounted to 0.89% of foreign land investment. Commodity crop expansion in SSA appears largely driven by small- and medium-scale farmers rather than industrial plantations. Land-use changes associated with large-scale investments remain to be observed in many countries. Although domestic demand for commodity crops was associated with most agricultural expansion, we provide evidence of a growing influence of distant markets on land-use change in SSA. Understanding land use change pressures on African tropical forests is critical for curtailing the loss of these important ecosystems.