Boehm, M.

Lemke, R.

English

University of Saskatchewan Research Archive

Greenhouse Gas Management in AgricultureReynald Lemke and Marie BoehmAgriculture & Agri-Food Canada, Saskatoon, SK.2“Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic GHG concentrations.”“Unmitigated climate change would, in the long term, be likely to exceed the capacity of natural, managed and human systems to adapt.”Climate Change 2007:Synthesis Report - (IPCC: http://www.ipcc.ch/)Background…….3Climate change..... a difficult policy issue Long lag between cause (GHG emissions) and effect (climate change) Cannot prove that current actions will cause future interference with the climate system• Sound theoretical basis for concern (physics); compelling supporting evidence (measurements and modelling) • Ultimately, requires decisions based on uncertain predictions  UNFCCC/IPCC have taken “precautionary approach”• If consequences are irreversible and potentially dangerous, it is reasonable to take mitigative action even with uncertainty• prevention requires action now• There are many win-win opportunities – at least act on those4A particular dilemma for agriculture By 2050 projected global population will approach 9 billion Food production will need to double possibly in addition to increased demand for bioenergy production 80% of the future increases in food production will have to come from intensification (FAO)• Cannot rely on area expansion but• Yield growth rates are decelerating, and • Land and water resources are already stressed• Peak oil is on the horizon (or already here?) Greatest impact of climate change in most vulnerable countries that lack adaptive capacity5International challenge for agricultureHow to mitigate agricultural emissions and ensure food security in spite of climate change impacts?6Current State of Play - Copenhagen Accord• Key outcome of Copenhagen meeting• COP only ‘taking note of’ but can be the basis for a legally-binding agreement• Drafted by countries that represent 80% of global emissions (Kyoto countries only represent 30% of global emissions) and 4 billion people7Copenhagen Accord• Copenhagen Accord supported by vast majority of countries• Limits warming to 2ºC globally• Sets economy-wide emission reduction targets for developed and developing countries• Contains financing and new mechanisms for climate action• $30 billion US fast – track• $100 billion by 2020• Adaptation, technology and REDD mechanisms to help least developed and vulnerable countries • Work will continue throughout 2010 with goal of legally binding agreement in Mexico in December 2010 – including a goal for action in the agriculture sector8Domestic policy challenge• How should Canadian agriculture sector react to international climate policy?• What actions can farmers take to mitigate agricultural emissions?9Mitigation policy for agriculture in the context of the precautionary principle• Focus on practices that mitigate climate change and provide economic and/or other environmental benefitsExamples– Improve input use efficiency• Less N2O emissions from N fertilizer is more N for the crop• Less CH4 loss from livestock is more feed converted to biomass– Improve resilience to impacts of climate change• Farming systems that are vulnerable to climate change impacts will not survive in the long-term– Low-GHG intensity• Reducing GHG emissions per unit of product to ensure that food is produced with greatest efficiency possible• Increasing international interest  - carbon footprint, life cycle analysis of food systems.10Canada’s Greenhouse Gas Emissions Trend500550600650700750800199019921994199619982000200220042006Mt CO2-equivalentsProposed “Copenhagen” target(607 Mt by 2020)11Canada’s anthropogenic GHG emissions by sector3%82% 7%8%Energy Industry Agriculture WasteAgriculture emissions by gasN2O57%CH442%Environment Canada, National Inventory Report: 1990-2007, GHG Sources and Sinks in Canada12nitrification NH4+ NO3-NO2-N2NO2-NO2-chemodenitrificationN2N2ON2ON2O denitrificationnitrifier-denitrificationSources of soil-emitted N2O13Original derivation of IPCC coefficient for soil-emitted N2OTotal N2O DIRECT = Ninputs * EF1y = 1 + 0.0125x 0.01.02.03.04.00 50 100 150 200N rateN 2O emitted“background” anthropogenic14Conceptualization of the influence of WFPS on nitrification,denitrification, and N2O emission rates40% 50% 60% 70% 80% 90% 100%water-filled pore space proportion of totalnitrification denitrification15Tier II methodology for calculating N2O Emissions.Soil_N2O = Ninputs_N2O + “modifiers”Ninputs_N2O = (Fertilizer N + residue N + manure N)*EF1600.0020.0040.0060.0080.010.0120.0140.0160.0180 0.2 0.4 0.6 0.8 1 1.2P/PE (mm mm-1)EFeco (kg N2O-N kg N-1)EFeco = 0.022 P/PE - 0.0048EFeco < 0.0016 were set = 0.0016EFeco > 0.017 were set = 0.017Québec & Ontarion= 72Grey & Black soilsn= 155Brown & Dark Brown soilsn= 48EF = f (P/PE)Emission factor as a function of local climate(Source: Rochette et al., 2008)17Calculating N2O EmissionsEFeco = EF calculated specifically for each ecodistrict  Reference situation = ‘‘a non-irrigated soil located in well- drained portions of the landscapeunder conventional tillage practices’’18Calculating N2O EmissionsSoil_N2O = Ninputs_N2O + fallow_N2O + irrigation_N2O + topography_N2O + tillage_N2O + texture_N2OSource: Rochette et al. (2008)19Soil N2O emissions: TillageN2Otill = N2Oinputs x (RFtill -1) x FtillRegion tilled no-till RFtillEast 1.71 kg N ha-1 1.90 kg N ha-1 1.1Prairies 0.53 kg N ha-1 0.44 kg N ha-1 0.8RFtill = Tillage Ratio FactorFtill = Fraction of agricultural land under no-till20Soil N2O emissions: SummerfallowN2Ocrop = N2O back + N2O N-inputsN2Ofallow  = N2O back + N2O fallow-effectN2Ocrop = N2O fallowN2O back + N2O fallow-effect = N2O back + N2O N inputsN2O fallow_effect = N2O N inputs21Soil N2O emissions: TopographyLanscape type Positions associated with Ftopo Ftopo Inclined +Dissected none 0 Steep none 0 Undulating Depressions 0.08 Level Depressions 0.06 Terraced Depressions 0.10 Hummocky + Knoll + Kettle Depressions + ½  lower slope 0.16 Rolling Depressions + ½  lower slope 0.16 Ridged Depressions + ½  lower slope 0.10 All cultivated land  0.10  Topography_N2O = N2Oinputs x (0.017- EF)/EF  x FtopoFtopo = Fraction of agricultural land where soil moisture is likely to remain high Assumed that N2O emissions in lower sections of the landscape are equal to those where P/PE =1.  Accordingly, an EF value of 0.017 kg N2O kg-1 N was used in these areas.(Source: Rochette et al., 2008)22Indirect N2O emissionsNvolat = Fraction of N input lost via volatilization– Fertilizer N = N applied * 0.1 – Organic N = N applied * 0.3 • EF = 0.1Indirect_N2O = (Nleach)*EF + (Nvolat)*EF23Indirect loss of N2ONleach = Fraction of N input lost via leaching • IPCC Tier I - Nleach varies between 0.3 and 0.05• Canadian Tier II – accepted 0.3 and 0.05 as upper and lower boundaries and developed relationship with P/PE• EF = 0.075Indirect_N2O = (Nleach)*EF + (Nvolat)*EF24Summary: Inventory of soil-emitted N2O• Emissions factor now calculated for each year and each ecodistrict based on a relationship with P/PE• Emissions for summer fallow assumed equal to cropped situation (N2O from “crops” a proxy for N2O from fallow) • Emission factor adjusted for landscape position and a modifier included for tillage• Leaching losses calculated based on relationship with P/PE  25The Alberta example …Climate Change and Emissions Management Act“Establishing market demand through regulated emission reduction targets for large emitters;” and“ Enabling market supply through allowing emission offsets as a compliance option for regulated emitters.”Alberta Offset System Protocols - Quantification protocol for tillage system management (approved)- Draft nitrous oxide emission reduction quantification protocol- Draft summerfallow reduction agricultural practices quantification protocolhttp://carbonoffsetsolutions.climatechangecentral.com26Alberta Offset System ProtocolsQuantification protocol for tillage system management (approved)• - Principle motivation is carbon sequestration• - Nitrous oxide reduction calculation is includedDraft summerfallow reduction agricultural practices quantification protocol• - principle motivation is carbon sequestration• - neutral for nitrous oxide emissions Draft nitrous oxide reduction quantification protocol  • - based on the “4R Nitrogen Stewardship Plan”www.ipni.net/4r27Nitrogen fertility management  Fall applied N increases risk of N2O loss during spring thaw and pre-plant period Risk of N2O loss greatest from lower slopes & depressions• Precision application? • coated products or nitrification inhibitors ? N applied in excess of crop needs will increase risk of N2O loss• Rate determined by soil test or N balance calculation ?  Pulse crops in rotation reduces fertilizer N requirements and N2O emission28Negotiating challenge: two views of the future of agricultureProductivity and efficiency(how to feed 9 billion people)Diversity and resilience(how to adapt)versusAgribusinessBiotechnologyHigh inputGlobal marketsTraditional methodsOrganicLow inputLocal marketsversusThis is not a dichotomy - practical solutions will have to draw from both sides to meet local conditions and needsDeveloped countriesIndustryDeveloping countriesENGOs, indigenous peopleversus29

Greenhouse gas management in agriculture

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Greenhouse gas management in agriculture

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