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- Cintas Sanchez, Olivia, 1982
(författare)
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On the contribution of forest bioenergy to climate change mitigation
- 2016
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Greenhouse gas (GHG) emissions have to be drastically reduced to keep global warming below 2 degrees. Bioenergy can play a role in climate change mitigation by substituting for fossil fuels. However, climate benefits associated with forest-based bioenergy are being questioned, and studies arrive at contrasting conclusions, mainly due to diverging methodological choices and assumptions. This thesis combines three papers to bring together different methodological perspectives to improve the assessment and understanding of the contribution of forest bioenergy to climate change mitigation. The thesis concerns carbon balances and GHG-mediated climate effects associated with the use of forest biomass for energy in Sweden. More specifically, the focus is on methodological choices including definition of spatial and temporal system boundaries, and character of forests and forest product markets, e.g., forest owners’ responses to changes in demand for forest products, and how different assessment scales and metrics capture the difference in timing between emission and sequestration of carbon in forests that are managed with long rotations.The results show that the assessed climate benefits of promoting forest bioenergy systems can differ depending on the scale of the assessment, the forest structure, market prospects for bioenergy and other forest products, and energy system developments. Based on these findings, we recommend that assessments intending to support policy-making (i) consider how an increase in bioenergy demand affects the forest carbon stock at the landscape level, i.e., the scale at which forest operations are typically coordinated; (ii) be context-specific rather than feedstock-specific; (iii) consider changes in forest management driven by increased bioenergy demand, which can affect forest carbon stock and climate change mitigation; (iv) combine the assessment with energy system modeling to understand the size and development of bioenergy demand and different technology pathways; and (v) acknowledge short-term vs. long-term benefits, as some bioenergy systems could be associated with initial forest stock losses but great long-term benefits that can be overlooked if the temporal scope is too narrow. The latter is especially relevant when the ultimate goal is a long-term climate target, e.g.., the 2-degree target.This thesis also shows that the Swedish forest sector can make an important contribution to the 2045 goal of climate neutrality, i.e., no net GHG emissions to the atmosphere, by supplying forest fuels and other products while maintaining or enhancing carbon storage in vegetation, soils, and forest products. The results indicate that the neutrality target can only be reached by 2050 if the net carbon balance effect from the forest is considered. Additionally, measures to enhance forest productivity can increase the output of forest products (including bioenergy) and also enhance carbon sequestration in forests and products, reaching net negative emissions earlier. All in all, studies intending to support policy- and decision-making may provide more relevant information if the focus is shifted from assessing individual bioenergy systems to consider all forest products and how forest management planning as a whole is affected by bioenergy incentives - and how this in turn affects carbon balances in forest landscapes and forest product pools. Studies should preferably employ several alternative scenarios for critical factors, including policy options, forest product markets, and energy technology pathways.
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| 2. |
- Cintas Sanchez, Olivia, 1982, et al.
(författare)
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The climate effect of increased forest bioenergy use in Sweden: evaluation at different spatial and temporal scales
- 2016
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Ingår i: Wiley Interdisciplinary Reviews: Energy and Environment. - : Wiley. - 2041-8396 .- 2041-840X. ; 5:3, s. 351-369
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Tidskriftsartikel (refereegranskat)abstract
- Bioenergy from boreal forests managed for productive purposes (e.g., pulp, timber) is commonly held to offer attractive options for climate change mitigation. However, this view has been challenged in recent years. Carbon balances, cumulative radiative forcing, and average global temperature change have been calculated for a variety of bioenergy management regimes in Swedish forests and the results support the view that an increased use of forest biomass for energy in Sweden can contribute to climate change mitigation, although methodological (e.g. spatial scales) and parameter value choices influence the results significantly. We show that the climate effect of forest-based bioenergy depends on the forest ecosystems and management, including biomass extraction for bioenergy and other products, and how this management changes in response to anticipated market demands; and on the energy system effects, which determine the fossil carbon displacement and other greenhouse gas (GHG) mitigation effects of using forest biomass for bioenergy and other purposes. The public and private sectors are advised to consider information from comprehensive analyses that provide insights about energy and forest systems in the context of evolving forest product markets, alternative policy options, and energy technology pathways in their decision-making processes.
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