Sustainable pathways of biofuel crop expansion in the Tropics?
Gibbs, University of Wisconsin-Madison, email@example.com
Johnston, University of Wisconsin-Madison, firstname.lastname@example.org
Foley, University of Wisconsin-Madison, email@example.com
We are in the midst of a major worldwide shift from fossil fuel to renewable bioenergy, and some predict that biofuels could fulfill 25% of global energy needs within the next 15-20 years. This move away from fossil fuels could curb greenhouse gas emissions and be a major positive force for global climate mitigation. Without thoughtful planning, however, the biofuels boom may spur tropical deforestation, which currently accounts for ~20% of annual worldwide emissions of carbon dioxide. Expansion of biofuel crops will undoubtedly increase these emissions, potentially negating a major benefit of bioenergy. Here, we examine the likely sources for newly expanded agricultural land in the Amazon Basin and across the tropics. We also calculate the “carbon payback time”, or how long it will take for annual carbon savings of liquid biofuel use to offset emissions from the initial land conversion in the tropics. The carbon payback time for even the most productive crops is ~30 to 400 years if biofuel crops expand into tropical forests.
Science Theme: LC (Land Use and Land Cover Change)