Cited by 1347 — C. Mbow, N. H. Ravindranath, C. W. Rice, C. Robledo Abad, A. Romanovskaya testing of 50 % biofuel in jet fuel for commercial domestic and trans-.
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811Agriculture, Forestry and Other Land Use (AFOLU)Coordinating Lead Authors: Pete Smith (UK), Mercedes Bustamante (Brazil) Lead Authors: Helal Ahammad (Australia), Harry Clark (New Zealand), Hongmin Dong (China), Elnour A. Elsiddig (Sudan), Helmut Haberl (Austria), Richard Harper (Australia), Joanna House (UK), Mostafa Jafari (Iran), Omar Masera (Mexico), Cheikh Mbow (Senegal), Nijavalli H. Ravindranath (India), Charles W. Rice (USA), Carmenza Robledo Abad (Switzerland / Colombia), Anna Romanovskaya (Russian Federation), Frank Sperling (Germany / Tunisia), Francesco N. Tubiello (FAO / USA / Italy)Contributing Authors: Göran Berndes (Sweden), Simon Bolwig (Denmark), Hannes Böttcher (Austria / Germany), Ryan Bright (USA / Norway), Francesco Cherubini (Italy / Norway), Helena Chum (Brazil / USA), Esteve Corbera (Spain), Felix Creutzig (Germany), Mark Delucchi (USA), Andre Faaij (Netherlands), Joe Fargione (USA), Gesine Hänsel (Germany), Garvin Heath (USA), Mario Herrero (Kenya), Richard Houghton (USA), Heather Jacobs (FAO / USA), Atul K. Jain (USA), Etsushi Kato (Japan), Oswaldo Lucon (Brazil), Daniel Pauly (France / Canada), Richard Plevin (USA), Alexander Popp (Germany), John R. Porter (Denmark / UK), Benjamin Poulter (USA), Steven Rose (USA), Alexandre de Siqueira Pinto (Brazil), Saran Sohi (UK), Benjamin Stocker (USA), Anders Strømman (Norway), Sangwon Suh (Republic of Korea / USA), Jelle van Minnen (Netherlands) Review Editors: Thelma Krug (Brazil), Gert-Jan Nabuurs (Netherlands) Chapter Science Assistant: Marina Molodovskaya (Canada / Uzbekistan)
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812812Agriculture, Forestry and Other Land Use (AFOLU) 11Chapter 11This chapter should be cited as:Smith P., M. Bustamante, H. Ahammad, H. Clark, H. Dong, E. A. Elsiddig, H. Haberl, R. Harper, J. House, M. Jafari, O. Masera, C. Mbow, N. H. Ravindranath, C. W. Rice, C. Robledo Abad, A. Romanovskaya, F. Sperling, and F. Tubiello, 2014: Agricul -ture, Forestry and Other Land Use (AFOLU). In: Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Edenhofer, O., R. Pichs-Madruga, Y. Sokona, E. Farahani, S. Kadner, K. Seyboth, A. Adler, I. Baum, S. Brunner, P. Eickemeier, B. Kriemann, J. Savolainen, S. Schlömer, C. von Stechow, T. Zwickel and J.C. Minx (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.
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813813Agriculture, Forestry and Other Land Use (AFOLU) 11Chapter 11ContentsExecutive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81611.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81811.2 New developments in emission trends and drivers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81911.2.1 Supply and consumption trends in agriculture and forestry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82211.2.2 Trends of GHG emissions from agriculture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82211.2.3 Trends of GHG ˜uxes from forestry and other land use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82511.3 Mitigation technology options and practices, and behavioural aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82911.3.1 Supply-side mitigation options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82911.3.2 Mitigation effectiveness (non- permanence: saturation, human and natural impacts, displacement) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83211.4 Infrastructure and systemic perspectives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83611.4.1 Land: a complex, integrated system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83611.4.2 Mitigation in AFOLU Š feedbacks with land-use competition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83711.4.3 Demand-side options for reducing GHG emissions from AFOLU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83811.4.4 Feedbacks of changes in land demand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84111.4.5 Sustainable development and behavioural aspects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84211.5 Climate change feedback and interaction with adaptation (includes vulnerability) . . . . . . . . . . . . 84311.5.1 Feedbacks between ALOFU and climate change . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84511.5.2 Implications of climate change on terrestrial carbon pools and mitigation potential of forests . . . . . . . . . 84511.5.3 Implications of climate change on peatlands, grasslands, and croplands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84511.5.4 Potential adaptation options to minimize the impact of climate change on carbon stocks in forests and agricultural soils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84611.5.5 Mitigation and adaptation synergies and tradeoffs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 846
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814814Agriculture, Forestry and Other Land Use (AFOLU) 11Chapter 1111.6 Costs and potentials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84711.6.1 Approaches to estimating economic mitigation potentials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84811.6.2 Global estimates of costs and potentials in the AFOLU sector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84811.6.3 Regional disaggregation of global costs and potentials in the AFOLU sector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84911.7 Co-bene˚ts, risks, and spillovers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85211.7.1 Socio-economic effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85311.7.2 Environmental effects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85511.7.3 Public perception . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85711.7.4 Spillovers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85811.8 Barriers and opportunities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85811.8.1 Socio-economic barriers and opportunities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85811.8.2 Institutional barriers and opportunities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85811.8.3 Ecological barriers and opportunities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85911.8.4 Technological barriers and opportunities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85911.9 Sectoral implications of transformation pathways and sustainable development . . . . . . . . . . . . . . 85911.9.1 Characterization of transformation pathways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86011.9.2 Implications of transformation pathways for the AFOLU sector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86211.9.3 Implications of transformation pathways for sustainable development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86211.10 Sectoral policies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86211.10.1 Economic incentives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86411.10.2 Regulatory and control approaches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86411.10.3 Information schemes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86811.10.4 Voluntary actions and agreements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86811.11 Gaps in knowledge and data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 868
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815815Agriculture, Forestry and Other Land Use (AFOLU) 11Chapter 1111.12 Frequently Asked Questions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86911.13 Appendix Bioenergy: Climate effects, mitigation options, potential and sustainability implications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87011.13.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87011.13.2 Technical bioenergy potential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87011.13.3 Bioenergy conversion: technologies and management practices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87311.13.4 GHG emission estimates of bioenergy production systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87711.13.5 Aggregate future potential deployment in integrated models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88211.13.6 Bioenergy and sustainable development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88311.13.7 Tradeoffs and synergies with land, water, food, and biodiversity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 883References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 887
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816816Agriculture, Forestry and Other Land Use (AFOLU) 11Chapter 11Executive SummaryAgriculture, Forestry, and Other Land Use (AFOLU) is unique among the sectors considered in this volume, since the mitiga – tion potential is derived from both an enhancement of removals of greenhouse gases (GHG), as well as reduction of emissions through management of land and livestock (robust evidence; high agreement). The land provides food that feeds the Earth™s human population of ca. 7 billion, ˜bre for a variety of purposes, livelihoods for billions of people worldwide, and is a critical resource for sustain – able development in many regions. Agriculture is frequently central to the livelihoods of many social groups, especially in developing coun – tries where it often accounts for a signi˜cant share of production. In addition to food and ˜bre, the land provides a multitude of ecosystem services; climate change mitigation is just one of many that are vital to human well-being (robust evidence; high agreement ). Mitigation options in the AFOLU sector, therefore, need to be assessed, as far as possible, for their potential impact on all other services provided by land. [Section 11.1] The AFOLU sector is responsible for just under a quarter (~10 Œ 12 GtCO2eq / yr) of anthropogenic GHG emissions mainly from deforestation and agricultural emissions from livestock, soil and nutrient management ( robust evidence; high agreement ) [11.2]. Anthropogenic forest degradation and biomass burning (forest ˜res and agricultural burning) also represent relevant contributions. Annual GHG emissions from agricultural production in 2000 Œ 2010 were estimated at 5.0 Œ 5.8 GtCO2eq / yr while annual GHG ˚ux from land use and land-use change activities accounted for approximately 4.3 Œ 5.5 GtCO2eq / yr. Leveraging the mitigation potential in the sec -tor is extremely important in meeting emission reduction targets (robust evidence; high agreement ) [11.9]. Since publication of the IPCC Fourth Assessment Report (AR4), emissions from the AFOLU sector have remained similar but the share of anthropogenic emissions has decreased to 24 % (in 2010), largely due to increases in emissions in the energy sector ( robust evidence, high agreement ). In spite of a large range across global Forestry and Other Land Use (FOLU) ˚ux estimates, most approaches indicate a decline in FOLU carbon dioxide (CO2) emis-sions over the most recent years, largely due to decreasing defores – tation rates and increased afforestation (limited evidence, medium agreement). As in AR4, most projections suggest declining annual net CO2 emissions in the long run. In part, this is driven by technological change, as well as projected declining rates of agriculture area expan – sion, which, in turn, is related to the expected slowing in population growth. However, unlike AR4, none of the more recent scenarios proj – ects growth in the near-term [11.9]. Opportunities for mitigation include supply-side and demand-side options. On the supply side, emissions from land-use change (LUC), land management and livestock management can be reduced, terrestrial carbon stocks can be increased by sequestration in soils and biomass, and emissions from energy production can be saved through the substitution of fossil fuels by biomass (robust evidence; high agree – ment) [11.3]. On the demand side, GHG emissions could be mitigated by reducing losses and wastes of food, changes in diet and changes in wood consumption (robust evidence; high agreement ) [11.4] though quantitative estimates of the potential are few and highly uncertain. Increasing production without a commensurate increase in emissions also reduces emission intensity, i. e., the GHG emissions per unit of product that could be delivered through sustainable intensi˜cation; another mechanism for mitigation explored in more detail here than in AR4. Supply-side options depend on the ef˜cacy of land and livestock management ( medium evidence; high agreement ) [11.6]. Considering demand-side options, changes in human diet can have a signi˜cant impact on GHG emissions from the food production lifecycle (medium evidence; medium agreement ) [11.4]. There are considerably different challenges involved in delivering demand-side and supply-side options, which also have very different synergies and tradeoffs. The nature of the sector means that there are potentially many barriers to implementation of available mitigation options, including accessibility to AFOLU ˚nancing, poverty, institutional, ecological, technological development, diffusion and transfer barriers (medium evidence; medium agreement ) [11.7, 11.8]. Simi – larly, there are important feedbacks to adaptation, conservation of nat – ural resources, such as water and terrestrial and aquatic biodiversity (robust evidence; high agreement ) [11.5, 11.8]. There can be competi – tion between different land uses if alternative options to use available land are mutually exclusive, but there are also potential synergies, e. g., integrated systems or multi-functionality at landscape scale (medium evidence; high agreement ) [11.4]. Recent frameworks, such as those for assessing environmental or ecosystem services, provide one mecha – nism for valuing the multiple synergies and tradeoffs that may arise from mitigation actions (medium evidence; medium agreement ) [11.1]. Sustainable management of agriculture, forests, and other land is an underpinning requirement of sustainable development (robust evi- dence; high agreement ) [11.4].AFOLU emissions could change substantially in transformation pathways, with signi˚cant mitigation potential from agriculture, forestry, and bioenergy mitigation measures (medium evidence; high agreement). Recent multi-model comparisons of idealized imple – mentation transformation scenarios ˜nd land emissions (nitrous oxide, N2O; methane, CH 4; CO 2) changing by Œ 4 to 99 % through 2030, and 7 to 76 % through 2100, with the potential for increased emissions from land carbon stocks. Land-related mitigation, including bioenergy, could contribute 20 to 60 % of total cumulative abatement to 2030, and 15 to 40 % to 2100. However, policy coordination and implementation issues are challenges to realizing this potential [11.9]. Large-scale biomass supply for energy, or carbon sequestration in the AFOLU sector provide ˚exibility for the development of mitigation technologies in the energy supply and energy end-use sectors, as many technologies already exist and some of them are commercial (limited evidence; medium agree – ment) [11.3], but there are potential implications for biodiversity, food security, and other services provided by land ( medium evidence, high
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818818Agriculture, Forestry and Other Land Use (AFOLU) 11Chapter 1111.1 Introduction Agriculture, Forestry, and Other Land Use (AFOLU 1) plays a central role for food security and sustainable development (Section 11.9). Plants take up carbon dioxide (CO2) from the atmosphere and nitrogen (N) from the soil when they grow, re-distributing it among different pools, including above and below-ground living biomass, dead residues, and soil organic matter. The CO 2 and other non-CO2 greenhouse gases (GHG), largely methane (CH4) and nitrous oxide (N2O), are in turn released to the atmo -sphere by plant respiration, by decomposition of dead plant biomass and soil organic matter, and by combustion (Section 11.2). Anthropo – genic land-use activities (e. g., management of croplands, forests, grass -lands, wetlands), and changes in land use / cover (e. g., conversion of for -est lands and grasslands to cropland and pasture, afforestation) cause changes superimposed on these natural ˚uxes. AFOLU activities lead to both sources of CO 2 (e. g., deforestation, peatland drainage) and sinks of CO2 (e. g., afforestation, management for soil carbon sequestration), and to non-CO2 emissions primarily from agriculture (e. g., CH 4 from livestock and rice cultivation, N 2O from manure storage and agricultural soils and biomass burning (Section 11.2).The main mitigation options within AFOLU involve one or more of three strategies: reduction / prevention of emissions to the atmosphere by conserving existing carbon pools in soils or vegetation that would otherwise be lost or by reducing emissions of CH4 and N2O (Section 11.3); sequestration Š enhancing the uptake of carbon in terrestrial reservoirs, and thereby removing CO 2 from the atmosphere (Section 11.3); and reducing CO 2 emissions by substitution of biological prod-ucts for fossil fuels (Appendix 1) or energy-intensive products (Sec – tion 11.4). Demand-side options (e. g., by lifestyle changes, reducing losses and wastes of food, changes in human diet, changes in wood consumption), though known to be dif˜cult to implement, may also play a role (Section 11.4). Land is the critical resource for the AFOLU sector and it provides food and fodder to feed the Earth™s population of ~7 billion, and ˜bre and fuel for a variety of purposes. It provides livelihoods for billions of people worldwide. It is ˜nite and provides a multitude of goods and ecosystem services that are fundamental to human well-being (MEA, 2005). Human economies and quality of life are directly dependent on the services and the resources provided by land. Figure 11.1 shows the many provisioning, regulating, cultural and supporting services pro -vided by land, of which climate regulation is just one. Implementing mitigation options in the AFOLU sector may potentially affect other services provided by land in positive or negative ways. In the Intergovernmental Panel on Climate Change (IPCC) Second Assessment Report (SAR) (IPCC, 1996) and in the IPCC Fourth Assess -1 The term AFOLU used here consistent with the (IPCC, 2006) Guidelines is also consistent with Land Use, Land-Use Change and Forestry (LULUCF) (IPCC, 2003), and other similar terms used in the scienti˜c literature. ment Report (AR4) (IPCC, 2007a), agricultural and forestry mitigation were dealt with in separate chapters. In the IPCC Third Assessment Report (TAR) (IPCC, 2001), there were no separate sectoral chapters on either agriculture or forestry. In the IPCC Fifth Assessment Report (AR5), for the ˜rst time, the vast majority of the terrestrial land surface, comprising agriculture, forestry and other land use (AFOLU) (IPCC, 2006), is considered together in a single chapter, though settlements (which are important, with urban areas forecasted to triple in size from 2000 global extent by 2030; Section 12.2), are dealt with in Chapter 12. This approach ensures that all land-based mitigation options can be considered together; it minimizes the risk of double counting or inconsistent treatment (e. g., different assumptions about available land) between different land categories, and allows the consideration of systemic feedbacks between mitigation options related to the land surface (Section 11.4). Considering AFOLU in a single chapter allows phenomena common across land-use types, such as competition for land (Smith et˛al., 2010; Lambin and Meyfroidt, 2011) and water (e. g., Jackson et˛al., 2007), co-bene˜ts (Sandor et˛al., 2002; Venter et˛al., 2009), adverse side-effects (Section 11.7) and interactions between mitigation and adaptation (Section 11.5) to be considered consistently. The complex nature of land presents a unique range of barriers and opportunities (Section 11.8), and policies to promote mitigation in the AFOLU sector (Section 11.10) need to take account of this complexity. In this chapter, we consider the competing uses of land for mitigation and for providing other services (Sections 11.7; 11.8). Unlike the chap – ters on agriculture and forestry in AR4, impacts of sourcing bioenergy from the AFOLU sector are considered explicitly in a dedicated appen – dix (Section 11.13). Also new to this assessment is the explicit con – sideration of food / dietary demand-side options for GHG mitigation in the AFOLU sector (Section 11.4), and some consideration of freshwa – ter ˜sheries and aquaculture, which may compete with the agriculture and forestry sectors, mainly through their requirements for land and / or water, and indirectly, by providing ˜sh and other products to the same markets as animal husbandry. This chapter deals with AFOLU in an integrated way with respect to the underlying scenario projections of population growth, economic growth, dietary change, land-use change (LUC), and cost of mitigation. We draw evidence from both ‚bottom-up™ studies that estimate mitiga – tion potentials at small scales or for individual options or technologies and then scale up, and multi-sectoral ‚top-down™ studies that consider AFOLU as just one component of a total multi-sector system response (Section 11.9). In this chapter, we provide updates on emissions trends and changes in drivers and pressures in the AFOLU sector (Section 11.2), describe the practices available in the AFOLU sector (Section 11.3), and provide re˜ned estimates of mitigation costs and potentials for the AFOLU sector, by synthesising studies that have become available since AR4 (Section 11.6). We conclude the chapter by identifying gaps in knowledge and data (Section 11.11), providing a selection of Frequently Asked Questions (Section 11.12), and presenting an Appendix on bioen -ergy to update the IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation (SRREN) (IPCC, 2011; see Section 11.13).
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819819Agriculture, Forestry and Other Land Use (AFOLU) 11Chapter 1111.2 New developments in emission trends and drivers Estimating and reporting the anthropogenic component of gross and net AFOLU GHG ˚uxes to the atmosphere, globally, regionally, and at country level, is dif˜cult compared to other sectors. First, it is not always possible to separate anthropogenic and natural GHG ˚uxes from land. Second, the input data necessary to estimate GHG emis -sions globally and regionally, often based on country-level statistics or on remote-sensing information, are very uncertain. Third, methods for estimating GHG emissions use a range of approaches, from simple default methodologies such as those speci˜ed in the IPCC GHG Guide -lines2 (IPCC, 2006), to more complex estimates based on terrestrial car -bon cycle modelling and / or remote sensing information. Global trends in total GHG emissions from AFOLU activities between 1971 and 2010 are shown in Figure 11.2; Figure 11.3 shows trends of major drivers of emissions. 2 Parties to the United Nations Framework Convention on Climate Change (UNFCCC) report net GHG emissions according to IPCC methodologies (IPCC, 2006). Reporting is based on a range of methods and approaches dependent on available data and national capacities, from default equations and emission fac – tors applicable to global or regional cases and assuming instantaneous emissions of all carbon that will be eventually lost from the system following human action (Tier 1) to more complex approaches such as model-based spatial analyses (Tier 3). Figure 11 .1 | Multiple ecosystem services, goods and bene˜ts provided by land (after MEA, 2005; UNEP-WCMC, 2011). Mitigation actions aim to enhance climate regulation, but this is only one of the many functions ful˜lled by land.
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820820Agriculture, Forestry and Other Land Use (AFOLU) 11Chapter 11Figure 11 .2 | Top: AFOLU emissions for the last four decades. For the agricultural sub-sectors emissions are shown for separate categories, based on FAOSTAT, (2013). Emissions from crop residues, manure applied to soils, manure left on pasture, cultivated organic soils, and synthetic fertilizers are typically aggregated to the category ‚agricultural soils™ for IPCC reporting. For the Forestry and Other Land Use (FOLU) sub-sector data are from the Houghton bookkeeping model results (Houghton et˚al., 2012). Emissions from drained peat and peat ˜res are, for the 1970s and the 1980s, from JRC / PBL (2013), derived from Hooijer et˚al. (2010) and van der Werf et˚al. (2006) and for the 1990s and the 2000s, from FAOSTAT, 2013. Bottom: Emissions from AFOLU for each RC5 region (see Annex II.2) using data from JRC / PBL (2013), with emissions from energy end-use in the AFOLU sector from IEA (2012a) included in a single aggregated category, see Annex II.9, used in the AFOLU section of Chapter 5.7.4 for cross-sectoral comparisons. The direct emission data from JRC / PBL (2013; see Annex II.9) represents land-based CO 2 emissions from forest and peat ˜res and decay that approximate to CO 2 ˛ux from anthopogenic emission sources in the FOLU sub-sector. Differences between FAOSTAT / Houghton data and JRC / PBL (2013) are discussed in the text. See Figures 11.4 and 11.6 for the range of differences among available databases for AFOLU emissions.
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821821Agriculture, Forestry and Other Land Use (AFOLU) 11Chapter 11Figure 11 .3 | Global trends from 1971 to 2010 in (top) area of land use (forest land Š available only from 1990; 1000 Mha) and amount of N fertilizer use (million tonnes), and (bottom) number of livestock (million heads) and poultry (billion heads). Data presented by regions: 1) Asia, 2) LAM, 3) MAF, 4) OECD-1990, 5) EIT (FAOSTAT, 2013). The area extent of AFOLU land-use categories, from FAOSTAT, (2013): ‚Cropland™ corresponds to the sum of FAOSTAT categories ‚arable land™ and ‚temporary crops™ and coincides with the IPCC category (IPCC, 2003); ‚Forest™ is de˜ned according to FAO (2010); countries reporting to UNFCCC may use different de˜nitions. ‚Permanent meadows and pasture™, are a subset of IPCC category ‚grassland™ (IPCC, 2003), as the latter, by de˜nition, also includes unmanaged natural grassland ecosystems. ˜˚˛˜˚˛˝˜˚˚˝˙˝˜˝˜˚˛˝˜˚˚˝˙˝˜˝˜˚˛˝˜˚˚˝˙˝˜˝˜˚˛˝˜˚˚˝˙˝˜˝˜˚˛˝˜˚˚˝˙˝˜˝˝ˆ˝˝ˆ˙ ˝ˆˇ ˝ˆ˘˜ˆ˝˜ˆ˙˜ˆˇ ˝˜˝ ˙˝ ˇ˝†˝˘˝˛˝˜ˆ˘˙ˆ˝˚˝˜˝˝ ˝˜ ˙ ˇ†˝˜˝˝˜†˝†˝˛ ˜ ˜˚˛˝˜˚˚˝˙˝˜˝˜˚˛˝˜˚˚˝˙˝˜˝˜˚˛˝˜˚˚˝˙˝˜˝˜˚˛˝˜˚˚˝˙˝˜˝˜˚˛˝˜˚˚˝˙˝˜˝˝˜˝˝˙˝˝ˆ˝˝ˇ˝˝˘˝˝ ˛˝˝˝˙ˇ˜˝ ˜˙ ˚˝˝˜˝˝˝˜˜˝˝˜˙˝˝˜ˆ˝˝˜ˇ˙˝˝˘˜˝ ˜˘˙˝˙˘˝˘˝˝˜˝˝˝ ˜˘˝˝˙˘˝˝˙˝˝˝ˆ
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