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Terrestrial Carbon Sequestration Adrian Martin. Global terrestrial C budgets Historical C emissions from land use change Global potential for LULUCF sequestration Reforestation Managing agricultural lands Institutional framework: Kyoto and CDM Social issues. IIED (2002).
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Terrestrial Carbon SequestrationAdrian Martin • Global terrestrial C budgets • Historical C emissions from land use change • Global potential for LULUCF sequestration • Reforestation • Managing agricultural lands • Institutional framework: Kyoto and CDM • Social issues
Net Ecosystem Productivity • Tropical Forests: 0.7- 5.9 MgC/ha/yr • Temperate forests: 0.8 – 7.0 MgC/ha/yr • Boreal forests: (<0?) – 2.5 MgC/ha/yr (IPCC 2001)
Historical Losses of Terrestrial Carbonthrough Land Use Change • Houghton (1990) estimates 121PgC lost 1850 – 1990 • De Fries et al (1999) further 60PgC lost prior to 1850 • Total 180PgC (280 from fossil fuels) • Approx 40% of this in atmosphere • Substantial (but ultimately limited) opportunities for modifying above and below ground carbon storage
Deforestation (cont.) • Deforestation responsible for estimated 90% of land use change emissions since 1850 • FAO (2001) Global Forest Resources Assessment 2000: • Gross annual loss 1990-2000: 14.6 million ha. • Net annual loss 1990-2000: 9.4million ha.
Forest Area Changes 1990-2000 Source: FAO 2001 Main cause of loss in tropical areas: conversion to agriculture
Global Potential: LULUCF • IPCC (1996 SAR) slowing deforestation and promoting reforestation could increase carbon stocks by 60-87PgC 1995-2050 • IPCC (2000 SRLULUCF) various management options could lead to global land-atmosphere flux of -1.3PgC/yr in 2010 and -2.5PgC/yr in 2040 • Plantations: Coniferous AUS & NZ: 10 t/ha/yr Coniferous EUR & US: 1.5 - 4.5 t/ha/yr Canada and former SU: 0.9 –1.2 t/ha/yr Tropical: 6.4 – 10 t/ha/yr
Repositories for extra carbon storage in terrestrial ecosystems
Predicted responses to different pools of soil organic matter for agricultural land converted to forest in northeastern United States of America (Gaudinski et al. 2000, in SRLULUCF)
Carbon sequestration through reforestation in the tropics 80 year average: 2.36Mg/ha/yr First 20 years: 6.17 Mg/ha/yr Silver et al (2000)
100 year average: 0.41 Mg/ha/yr First 20 years: 1.30 Mg/ha/yr Silver et al (2000) Silver et al (2000)
Can sequestration continue beyond 80 years? • One way is to harvest biomass for energy • The other is to ensure wood products have a long residence time Average estimated lifetime of wooden products [Germany] Fruewald & Scharai-Rad (2000) NB The fate of stored carbon in wood products is poorly known
Changing agricultural practices for below ground carbon storage • Historical loss of soil C through oxidation~ 50 PgC (Ingram & Fernandes, 2001) Average loss of carbon from top 100 cm of soil following conversion to agriculture = 15-40% Restoration possible through land use change and land management Global potential for C sequestration in agricultural soils 20-30 PgC over 50-100 years. (Paustian et al, 1997, cited in Ingram & Fernandes) Global sequestration from improved management of degraded lands 0.6 – 2 PgC/yr (Batjes, 1999, cited in Olsson & Ardo, 2002)
Carbon sequestration situation against soil organic carbon level. Source: Ingram & Fernandes (2001)
Main Issues Management Options • Soil erosion (especially loss of clay content) • Oxidation of carbon • Tillage • Temperature (e.g. reduced canopy) • Removal of organic residues • Drainage (aeration) • No tillage • Change of crops (raise NPP) • Fertiliser • Land use change – agroforestry, grassland • Fallow with grasses/legumes • Grazing of rangelands (see Schuman et al, 2002)
Olsson & Ardo (2002) case study from Sudan • Modelling of 6 different management systems in Sudanese cropland
Institutional Basis • Kyoto article 3 “removals by sinks resulting from direct human-induced land-use change and forestry activities, limited to afforestation, reforestation and deforestation since 1990, measured as verifiable changes in carbon stocks in each commitment period, shall be used to meet the commitments under this Article….” • Other sinks (such as agricultural soils may be included in the future) • 6th COP (resumed July 2001) agreement that reforestation and afforestation allowed under Clean Development Mechanism. • CDM – allows developed countries to meet their own commitments by funding emission reduction or carbon sequestration projects in developing countries. • Limited to 1% of a country’s baseline emissions (i.e. can meet about 20% of their reduction through CDM forestry projects).
Sequestration: a few concerns • Verification issues and transaction costs • What kind of forestry? • Large-scale? • Monocultures • Fast-growing exotics? • Whose development priorities? • Will sinks solve the problem? • Global feedbacks
FAO (2001) Global Forest Resources Assessment 2000, www.fao.org/forestry/fo/fra/main/index.jsp • Fruehwald, A. & Scharai-Rad (2000) Wood products as carbon sinks: a methodological approach,www.bib.fsagx.ac.be/coste21/ftp/2001-04-26/sharai-rad-sum.pdf • IPCC (2001) Climate Change 2001: the scientific basis. www.grida.no/climate/ipcc • IPCC (2000) Special Report on Land Use, Land Use Change and Forestry • IPCC (2001) Climate Change 2001: Mitigation. Section 4. Technological and Economic Potential of Options to Enhance, Maintain, and Manage Biological Carbon Reservoirs and Geo-engineering. • IIED (2002) Laying the Foundations for Clean Development: preparing the land use sector: a quick guide to the Clean Development Mechanism, London: International Institute for Environment and Development, www.cdmcapacity.org • Ingram, J. & Fernandes, E. (2001) Managing carbon sequestration in soils: concepts and terminology, Agriculture, Ecosystems and Environment, 87, 111-117. • Schuman, G., Janzen, H. & Herrick, J. (2002) Soil carbon dynamics and potential carbon sequestration by rangelands, Environmental Pollution, 116, 391-396 • Silver, W., Ostertag, R. & Lugo, A. (2000) The potential for carbon sequestration through reforestation of abandoned tropical agricultural and pasture lands, restoration Ecology, 8 (4), 394-407. • Olsson, L. & Ardo, J. (2002) Soil carbon sequestration in degraded semiarid agro-ecosystems – perils and potentials, Ambio 30 (6), 471-477. • Seely, B., Welham, C., Kimmins, H. (2002) ‘Carbon sequestration in a boreal forest ecosystem: results from the ecosystem simulation model, FORECAST’, Forest Ecology and Management 169, 123-135 • Ridgwell, A., Maslin, M. & Watson, A. (2002) Reduced effectiveness of terrestrial carbon sequestration due to an antagonistic response of ocean productivity, Geophysical Research Letters, 29 (6), 19