Climate Impacts of a Large-Scale Biofuels Expansion
Changes in land use from increased cultivation of biofuel crops can alter climate by increasing greenhouse gas emissions and by changing the reflective properties of Earth’s surface. A new modeling study by U.S. Department of Energy (DOE) researchers at the Massachusetts Institute of Technology Joint Program on the
Science and Policy of Global Change investigates how (1) land-use policies and economic factors influence where and how biofuel crops are planted, (2) potential implications for land-use change and
greenhouse gas emissions, and (3) the overall effect on global and regional climates. The study uses the DOE-supported Integrated Global Systems Model (IGSM) to simulate the climate effects of two
possible global biofuels futures—one that allows conversion of natural areas to meet the increased demand for land, and a second that encourages more intense use of existing managed land and restricts deforestation. Findings show that increased biofuel crop cultivation has a negligible effect on global temperature as
warming from increased greenhouse gas emissions from cultivation is balanced by cooling caused by increased surface reflectivity of cropland. Although global temperature will only be minimally
affected, more substantial regional warming may occur, and not necessarily in the regions where biofuel crops are grown. The model predicts the Amazon Basin and Central Africa will warm by as much
as 1.5°C. This effect is stronger in the first case that includes the conversion of forests into crop land. The effect is less pronounced when deforestation is limited. This indicates that future activities that promote land-use intensification may result in more tolerable future environmental conditions for local populations in tropical regions.
Hallgren, W., A. Schlosser, E. Monier, D. Kicklighter, A. Sokolov, and J. Melillo. 2013. “Climate
Impacts of a Large-Scale Biofuels Expansion,”Geophysical Research Letters, DOI: 10.1002/grl.50352.