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This section focuses on biofuels and forest products and their implications for land use and carbon dynamics. Section 4.4.5 discusses the in situ stock of carbon in growing forest; this section deals with carbon in forest products (Section 4.5.6) and the tradeoff between biofuels and in situ sequestration, including environmental and socioeconomic impacts (Sections 4.5.2, 4.5.3, 4.5.4 and 4.5.5). Fact Sheets at the end of this chapter deal with tradeoffs (Fact Sheet 4.20), biofuel from plantations (Fact Sheet 4.21), and biofuel from food and fiber production wastes such as sawdust (Fact Sheet 4.22).
When biomass displaces fossil fuels, the mitigation is captured as a decrease in fossil fuel use. The change in carbon stored in and on the land during biofuel growth must be accounted for separately. Tradeoffs between carbon storage and displacement of fossil fuels and energy-intensive materials have implications for land use and forest management. Article 3.3 of the Kyoto Protocol clearly distinguishes between biofuels and fossil fuels, establishing that biofuels are part of the cycling of carbon in the biosphere. Distinguishing biofuels from other fuels entails assessing options for managing carbon through the land-use change and forestry sector and looking at effects in the energy sector.
Globally, biofuel contributes about 14 percent of primary energy supply. Most biofuel use is traditional wood fuel in developing countries, but agricultural and forest wastes provide significant industrial feedstocks for energy production in developed economies (see Fact Sheets 4-21 and 4-22). Modern biofuel technology can provide electricity, gases, and transportation fuels and more efficiently support traditional uses of wood fuel, with environmental and social benefits. These benefits include job creation, productive use of surplus agricultural land, avoidance of health hazards from traditional wood burning, reduced urban and agricultural wastes, and nutrient recycling.
Agroforestry systems can provide multiple benefits, including energy, to rural communities, with synergies between sustainable development and GHG mitigation. Large-scale biofuel production raises questions, however, involving land availability and productivity (short- and long-term), species selection and mixtures, environmental sustainability, social and economic feasibility, and ancillary effects. Issues include fertilizer and pesticide requirements, nutrient cycling, energy balances, biodiversity impacts, hydrology and erosion, conflicts with food production, and the level of financial subsidies required.
Three broad questions arise if biofuels are to significantly reduce net CO2 emissions:
Underlying these questions is the tradeoff between stocking carbon in standing forest and producing a flow of woody biomass that displaces fossil fuels directly as biofuel or by displacing energy-intensive building materials.
The key message of this section is that managing land use for maximum on-site carbon storage may not always result in the most effective mitigation of GHG emissions. Increased carbon storage in the biosphere yields benefits, but over time greater mitigation is possible by managing the entire system-including the production and use of biofuels and other products.
From a policy perspective, the potential for biofuel displacement of fossil fuel is an order of magnitude greater than any other land-use change. It may also impact atmospheric carbon levels earlier and at lower cost than other energy sector measures. This consideration has significant precautionary potential against the possibility that undesired climate effects may occur at lower levels of atmospheric GHG than have been previously postulated (e.g., the threshold for rapid, nonlinear climate change, which is currently unknown) (Houghton, 1998).
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