Thilde Bech Bruun

Carbon outcomes of major land‐cover transitions in SE Asia: great uncertainties and REDD+ policy implications

Policy makers across the tropics propose that carbon finance could provide incentives for forest frontier communities to transition away from swidden agriculture (slash-and-burn or shifting cultivation) to other systems that potentially reduce emissions and/or increase carbon sequestration. However, there is little certainty regarding the carbon outcomes of many key land-use transitions at the center of current policy debates. Our meta-analysis of over 250 studies reporting above- and below-ground carbon estimates for different land-use types indicates great uncertainty in the net total ecosystem carbon changes that can be expected from many transitions, including the replacement of various types of swidden agriculture with oil palm, rubber, or some other types of agroforestry systems. These transitions are underway throughout Southeast Asia, and are at the heart of REDD+ debates. Exceptions of unambiguous carbon outcomes are the abandonment of any type of agriculture to allow forest regeneration (a certain positive carbon outcome) and expansion of agriculture into mature forest (a certain negative carbon outcome). With respect to swiddening, our meta-analysis supports a reassessment of policies that encourage land-cover conversion away from these [especially long-fallow] systems to other more cash-crop-oriented systems producing ambiguous carbon stock changes - including oil palm and rubber. In some instances, lengthening fallow periods of an existing swidden system may produce substantial carbon benefits, as would conversion from intensely cultivated lands to high-biomass plantations and some other types of agroforestry. More field studies are needed to provide better data of above- and below-ground carbon stocks before informed recommendations or policy decisions can be made regarding which land-use regimes optimize or increase carbon sequestration. As some transitions may negatively impact other ecosystem services, food security, and local livelihoods, the entire carbon and noncarbon benefit stream should also be taken into account before prescribing transitions with ambiguous carbon benefits.

Recognizing contemporary roles of swidden agriculture in transforming landscapes of southeast Asia.

Geography Department, AS2-04-21, 1 Arts Link, Kent Ridge. National University of Singapore117570, Singapore, emailgeoadz@nus.edu.sg†Program on Environment, East-West Center, 1601 East-West Road, Honolulu, HI 96848, U.S.A.‡Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore, 117543

The sustainability of cassava-based bioethanol production in southern Mali

The demand for biofuels has been rising, which has led developing countries to focus on production of feedstocks for biodiesel and bioethanol production. This has caused concerns for the impacts on food security, food prices and environmental sustainability. This paper examines a hypothetical case of cassava-based bioethanol production in southern Mali, assessing its environmental, economic and social sustainability. Results demonstrate that environmental sustainability of cassava-based bioethanol production depends on the ‘baseline’ chosen: Compared to the situation before the decline in cotton production 10 years ago, the carbon stocks will increase. However, if compared to the current situation, where considerable carbon stocks have accumulated in fallow fields, the loss of carbon will be substantial. Increased cassava production will create greater incomes and better temporal distribution of labour input. Analysis of the significance of current cassava production for food security shows that bioethanol production should be based on the attiéké variety of cassava, thereby avoiding interference with the important role of the bonouma in assuring food security in northern Mali. The key factor determining the economic feasibility is whether local farmers will be willing to supply cassava at a realistic price. The results indicate that this is likely to be the case.