Getting the Numbers Right: Revisiting Woodfuel Sustainability in the Developing World
Friday, November 13, 2015 : 1:50 PM
Gautier (Hyatt Regency Miami)
*Names in bold indicate Presenter
Traditional woodfuels, specifically firewood and charcoal used for cooking, water treatment, and space heating, represent approximately 55% of global wood harvest and 9% of primary energy supply. The current extent and future evolution of traditional woodfuel consumption are closely related to several key challenges in achieving sustainable development. Roughly 2.8 billion people worldwide, including the world’s poorest and most marginalized, burn wood to satisfy their basic energy needs. Woodfuels dependence negatively impacts public health, and can contribute to forest degradation and climate change. Woodfuel-based interventions have been enlisted in climate change mitigation efforts, primarily through the Clean Development Mechanism (CDM) under the United Nations Framework Convention on Climate Change (UNFCCC) but also through voluntary carbon markets. Nearly 300 carbon-offset projects are in various stages of implementation to reduce emissions from woodfuels by disseminating more efficient stoves or alternative technologies like biogas and solar cookers. However, it is not clear whether these efforts will be effective mitigation strategies. The climate change impacts of woodfuels depend on two independent factors. One factor is the combustion process, which releases CO2 and short-lived climate forcers (SLCFs) like black carbon (BC), methane, and other products of incomplete combustion. The second factor is the process of wood extraction itself. Nearly all landscapes produce a measurable increment of woody biomass over time, either as new growth, or as re-growth from previous harvesting. If woodfuels are harvested below this increment, then it is considered sustainable. However, if harvesting exceeds growth, then it will likely lead to forest degradation or deforestation. Under such circumstances, wood extraction is unsustainable, stocks of aboveground biomass are depleted, and atmospheric concentrations of CO2 increase. Interventions that reduce woodfuel consumption through increased efficiency or fuel switching can mitigate climate change by reducing SLCF emissions and reducing woodfuel consumption. However, the latter is only an effective mitigation strategy if wood extraction is unsustainable. Therefore, to understand the mitigation potential of woodfuel interventions, we must know the sustainability of woodfuel extraction. Few systematic studies of woodfuel sustainability have been conducted. Historically, woodfuel demand was considered a major driver of deforestation, but this position was challenged decades ago. More recent local or regional assessments find conflicting results, suggesting that geography is an important factor in determining woodfuel sustainability. The IPCC’s 4th Assessment claimed that 10% of global woodfuel is harvested unsustainably, but the 5th Assessment stressed that net emissions from woodfuels are still unknown. Here, we examine the discrepancies between estimates of woodfuel sustainability generated for carbon offset projects and estimates. We compare the methods utilized to generate each set of estimates, discuss why large differences arise, and explore the implications of harmonizing estimates made for carbon offset projects with the estimates that were produced by the pan-tropical study.