Directory UMM :Data Elmu:jurnal:A:Agricultural Systems:Vol66.Issue3.Dec2000:
Agricultural Systems 66 (2000) 145±166
www.elsevier.com/locate/agsy
Prioritizing greenhouse gas emission mitigation
measures for agriculture
S.N. Kulshreshtha a,*, B. Junkins b, R. Desjardins c
a
Department of Agricultural Economics, University of Saskatchewan, Saskatoon, SK, S7N 5A7, Canada
b
Policy Branch, Agriculture and Agri-food Canada, Ottawa, ON, Canada
c
Research Branch, Agriculture and Agri-food Canada, Ottawa, ON, Canada
Received 31 March 2000; received in revised form 10 August 2000; accepted 14 August 2000
Abstract
Since the signing of the Kyoto Protocol, a major eort has been launched in Canada to
identify cost-eective measures to reduce greenhouse gas (GHG) emissions. Agriculture is an
important contributor of methane and nitrous oxide in Canada. Over one-third of methane
and almost four-®fths of nitrous oxide emissions are from agriculture either directly or indirectly. By 2010 primary agricultural production is expected to generate about 67 megatonne (in
carbon dioxide equivalent), which increases to 97 megatonnes if all activities related to agricultural production are considered. Based on a systems approach, nutrient management was
selected as a possible scenario for mitigation. Estimated results indicate that this could lead to
a reduction of 0.9 megatonnes of GHG emissions at the primary agricultural production level,
and 1.2 megatonnes if the total agriculture and food sectors are included. Compared to the
direct emissions (from fertilizer rate and timing of application), the systems approach suggests
up to a doubling (from 0.4 to 0.92 Mt) of this reduction potential at the primary production
level. If one were to include emissions from the entire agriculture and agri-food system,
potential of up to tripling (from 0.4 to 1.23 Mt) the reduction of GHG can be achieved. The
need of a systems approach in prioritizing measures to reduce GHG emissions is supported by
this study. # 2001 Elsevier Science Ltd. All rights reserved.
Keywords: Greenhouse gas emission; Agriculture; Mitigation measures; Prioritizing; Canada
* Corresponding author. Tel.: +1-306-966-4014; fax: +1-306-966-8413.
E-mail address: kulshres@duke.usask.ca (S.N. Kulshreshtha).
0308-521X/01/$ - see front matter # 2001 Elsevier Science Ltd. All rights reserved.
PII: S0308-521X(00)00041-X
146
S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
1. Introduction
1.1. Background
Behind many of the natural disasters that have occurred during the 1990s lurks the
specter of human-induced global climate change. Armed with this information along
with other global changes as background, in 1992, some 176 countries met in Rio de
Janeiro to sign the UN Framework Convention on Climate Change. The major
objective of this Convention was to start the process of stabilizing the greenhouse
gas (GHG) concentrations in the atmosphere at a level below which they would not
contribute to climate change. Such reductions were viewed as instrumental in
achieving sustainable economic activity world wide. The Convention was supplemented by the Kyoto Protocol, which was a result of the Conference of the Parties,
which met in Kyoto, Japan, in December of 1997. At this meeting, further commitments in the form of targets for reducing GHG emissions were agreed upon. Under
this Kyoto Protocol, Canada signed an agreement to reduce its GHG emissions in
2010 (or during the period 2008±2012) to a level that is 6% lower than the 1990
level. As a baseline, these future emissions are projected under a non-intervention1
type of economic policy regime, called ``Business as usual'' (BAU).
Meeting the commitments made under the Kyoto Protocol requires careful planning, prioritization, and eventual implementation of mitigation measures and policies. In response to these commitments, the Government of Canada has instituted a
process of developing a ``National Implementation Strategy'' for mitigating GHG
emissions. Under this Program, a sum of $150 million has been allocated over 3
years for activities devoted to four themes: Technology Early Action Measures;
Science, Impacts and Adaptation; Foundation Analysis, and, Public Outreach2.
Under the Foundation Analysis theme, the Government has established 16 Issue
Tables, one of which deals with the agriculture and agri-food sector.
The Agriculture and Agri-Food Climate Change Table (henceforth referred to as
the Table) was set up to develop recommendations on various mitigation strategies
and govemment/industry policies (and programs) that would lead to a reduction in
the emissions of GHGs from agriculture, and thus help Canada meet its commitment under the Kyoto Protocol. Developing recommendations for various mitigation strategies that can be undertaken by producers requires information on several
fronts. These include, although are not necessarily limited to, the following:
1. development of emission estimates from agricultural production for the two
base periods Ð 1990 and 2010 under the BAU scenario;
2. identi®cation of mitigation strategies that can be implemented at the farm level
which would lead to reductions in agriculturally induced GHG emissions; and
1
This refers to a set of conditions where no speci®c measure to reduce emissions of GHG is undertaken
by the country.
2
The allocation of resources for these themes is as follows: Technology Early Action Measure Ð $6
million; Science, Impacts and Adaptation Ð $15 million; Foundation Analysis Ð $34 million; and Public
Outreach Ð $30 million.
S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
147
3. a comparative analysis of the eectiveness of each strategy and/or measures in
reducing emissions of GHGs from the agriculture and agri-food sector.
In addition, the Table was also expected to evaluate each mitigation strategy in
terms of broad socioeconomic, health, and environmental impacts, as well as to
assess various policy measures that may be required to ensure the adoption of the
recommended mitigation strategy3.
1.2. Need for the study
In order to make recommendations for the selected mitigation strategies for GHG
emission reduction, two types of tools are required: (1) tools for developing estimates of GHG emissions from the Agriculture and Agri-Food Sector (AAFS) in
Canada at both national and regional levels; and (2) tools for testing the eectiveness of selected mitigation strategies. The ®rst set of tools requires information on
the manner in which the adopted strategy would reduce GHG emissions in various
regions of Canada. Such information could be obtained from scienti®c experiments
under the assumed rate of adoption of the selected strategy.
In determining the emissions of GHGs from agriculture, two other considerations
are important.
1. Farm level activities, although a major contributor of GHG emissions from
agriculture, are related to other economic activities in the region as well as
those outside the region. Two types of linkages that exist are: backward linkages of the agriculture sector, and forward linkages. Backward linkages are
established between sectors when agriculture purchases its input needs from
other sectors. The forward linkages, in turn, are established between agriculture and those sectors that use its products for further value-added activities. Let us illustrate the interrelationships between mitigation strategies and
forward and backward linkages of agriculture. Let us assume that the selected
mitigation measure is the adoption of proper soil nutrient management on
farms. Such an adoption will lead to a change in the amount of nutrients added
to various crops in various regions of Canada. Depending upon the nature of
change, fertilizer input demand by farms would change. If the adjustment
aects yields, it may also aect the relative pro®tability of various crops and
may lead to a dierent production mix in dierent regions. Changes in the crop
mix may also lead to impacts on livestock production. Depending upon the
magnitude of such changes, this may further aect the competitiveness of
processing industries, and thereby aect emissions from the food processing
sub-sector. Such changes may be instrumental in bringing forth changes in
regional trade, and may aect production of various agricultural products
in other regions of Canada. Each of these changes would trigger an adjustment
of GHG emissions in Canada.
3
This analysis was considered outside the scope of the present study and, therefore, not reported here.
148
S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
2. Although most farmland is used for commercial agricultural pursuits, there are
other land use activities from the farm unit that have implications for GHG
emissions. This requires an examination of GHG emissions in a `whole farm'
context.
The above two considerations raise the central question: ``How should the emissions from agriculture be measured, particularly in the context of prioritizing various mitigation strategies in terms of their eectiveness for reducing GHG
emissions?'' In this study, the suggested framework is that of the entire agriculture
and agri-food system within a whole farm context. Adoption of a mitigation strategy by a producer may lead to other changes on the farm itself or at the regional
level. Therefore, in addition to developing appropriate estimates of GHG emissions
from agriculture, in the context of prioritizing various mitigation strategies, one
should also resolve the issue related to changes in other farm and/or regional level
activities resulting from the adoption of a given mitigation strategy.
2. Objectives and scope of the study
The major objective of this study is to develop a methodology for the estimation
of GHG emissions from Canadian agriculture using a combined agriculture and
agri-food sector approach and the whole farm context. This model is then used to
illustrate the changes in GHG emissions for various mitigation strategies. Results
are compared against model results where such linkages and whole farm context are
not considered.
The objectives of the study are accomplished through the following sub-objectives:
1. to develop a conceptual model of accounting for GHG emissions from the
AAFS that is appropriate in the context of developing recommendations for
the National Implementation Strategy for Canada on Climate Change;
2. to estimate various components of the conceptualized model for two base
periods Ð 1990, and 2010 under the BAU scenario;
3. to illustrate the estimated changes in emissions levels from the 2010 BAU case
for a simple scenario involving fertilizer use in various regions of Canada; and
4. to draw implications for using an appropriate methodology for prioritizing
GHG emission mitigation strategies for the Canadian AAFS.
The results presented here are part of the broader study of economic impacts of
GHG mitigation strategies under consideration by the Table4. However, discussion
in this study is limited to the examination of the GHG reduction potential for a
selected mitigation scenario. Results of all possible scenarios that can be considered
to meet Canadian agriculture's intended commitment under the Kyoto Protocol
are not reported here, since this requires another study. Other impacts, such as
4
The broader study is prepared by the Agriculture and Agri-Food Climate Change Table. Technical
aspects of various mitigation strategies are reported by Junkins et al. (2000).
S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
149
economic development impacts, ®scal impacts on various levels of governments, and
regional development are also not included.
3. Model
3.1. Considerations involved
Proper determination of GHG emissions for the AAFS can be guided by three
considerations: (1) the need to include all anthropogenic activities of the Canadian
AAFS that lead to GHG emissions; (2) the need to include all other farmland uses
besides agricultural pursuits, which is consistent with the `whole farm' approach;
and (3) the need for consistency with the Intergovernmental Panel for Climate
Change (IPCC) and Canada's Greenhouse Gas Inventory in accounting for and the
aggregation of GHG emissions from various economic activities.
The ®rst consideration led to relating agricultural production to all major forward
and backward linkages in the region. Two types of forward linkages were identi®ed
for agriculture: (1) those within primary agriculture; and (2) those beyond primary
agriculture. The former includes linkages between feed grain production and livestock
production, while the latter includes links with transportation of agricultural products beyond the farm gate (excluding that undertaken by producers), and processing
activities induced by the availability of raw material for value added activities.
The second aspect of accounting for all agricultural GHG emissions required the
inclusion of emissions from all farmlands and related activities within the agroecosystem level. Producers, in addition to cultivated lands, have uncultivated lands on
farms. Some of these are waterlogged (farm potholes or wetlands), some are woodlots (bushes and other vegetation), while others are forested. These land use activities either emit GHGs or sequester carbon.
The need for the third consideration was of paramount importance in the context
of the Kyoto Protocol, since measurement of success is done in a framework prescribed by the IPCC (Houghton et al., 1997). The recommendations of the IPCC
include a well-de®ned accounting framework for reporting inventories of GHG
emissions. Details of this framework are provided in Houghton et al. (1997). Two
stipulations in these guidelines are signi®cant for this study: (1) this framework
suggested that accounting for emissions from non-energy sources be done separately
from those from the energy-based inputs; and (2) soils as sinks of carbon are not
recognized under the Protocol at this time. Thus, under this framework, agricultural
soils as emitters of carbon dioxide (through the loss of soil carbon) are included in
Canada's inventory of agricultural emissions, but when soils reach an equilibrium
and beyond (i.e. becoming net sinks of carbon), carbon sequestration activities are
not included5.
5
At the time of writing this paper, two activities were underway: (1) the IPCC has just completed a
special report on the soils as sinks; and (2) negotiations are currently underway at various Conference of
the Parties to have sinks recognized as a part of the reduction targets under the Kyoto Protocol.
150
S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
In order to maintain consistency with the IPCC guidelines, as well as to conduct
the analysis incorporating the entire AAFS and the whole farm concept, estimated
emissions from on-farm energy use and soil carbon were kept separate. This led to
the model being more disaggregated in nature so as to allow for the accounting of
GHG emissions from agriculture under the IPCC framework, as well as providing a
more realistic picture of the total agricultural and agriculturally induced emissions
for Canada.
3.2. Overview of the model
The model used in the study was designed to estimate emissions of three main
GHGs associated with agriculture Ð carbon dioxide, methane, and nitrous oxide.
This distinction was necessitated by the fact that each of these gases have a dierent
global warming potential6. In order to ensure that the estimated emissions could be
used for the purposes of examining mitigation strategies for meeting the Kyoto
Protocol commitment, the model combined economic decision-making under a
given set of physical and economic environments with emissions of GHGs. The
resulting model was named the Canadian Economic and Emissions Model for
Agriculture (CEEMA). The CEEMA being used in this study is a second generation
model. The ®rst generation model CEEMA Version 1.0 is described in Kulsbreshtha
et al. (1999). An overview of the model used in this study is shown in Fig. 1.
The CEEMA is organized into three sub-models (or blocks): resource allocation,
science of GHG emissions, and estimation of total GHG emissions. The ®rst submodel depicts regional resource allocations for crops and livestock, and is named the
Canadian Regional Agriculture Sub-Model (CRAM). This sub-model was disaggregated using three criteria:
1. geographical location of agricultural activity;
2. type of enterprise (crop type or livestock type); and
3. technology of production (based on tillage systems, and crop rotations).
Agricultural activities were modeled on a provincial basis for all livestock production activities and for crop activities in regions outside the Prairies. However, crop
production in each of the three Prairie provinces was disaggregated on a sub-provincial level based on Census of Agriculture regions. Details on the number of
regions for the crop and livestock production blocks are shown in Table A1 in the
Appendix. Using the second criteria, all important crops were included in the model,
as shown in Table A2. Various crop production regions had dierent mixtures of
crops. Forages are important to the model since they provide an important linkage
between crop and livestock production. Major livestock production included in the
6
The term global warming potential refers to the relative contribution of each of these gases towards
radiative forcing, which is responsible for the climate change phenomenon. According to Environment
Canada (1997), these potentials are measured relative to carbon dioxide. Resulting values are called
``Carbon Dioxide Equivalent''.
S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
151
Fig. 1. Schematic of the components of CEEMA.
study were: beef cattle, dairy cattle, hogs, poultry, and sheep and lambs7. Using the
third criterion Ð technology of production, various crops in the three prairie provinces and sub-regions were modeled using summerfallow and stubble (continuous
cropping) rotations. Furthermore, wherever relevant, each of these production
practices were speci®ed using one of three tillage systems: conventional tillage,
minimum tillage, and no or zero tillage.
The second sub-model in CEEMA was the block where information on the science of GHG emissions was collected. This led to the development of emission
coecients for the various crop and livestock activities speci®ed in the resource
7
Sheep and lambs were included in the GHG emissions sub-model. These were exogenous to the
resource allocation sub-model.
152
S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
allocation model. The order of priority in selecting a particular emission coecient
should be regional, national (Canadian), and IPCC default values. In other words, if
region-speci®c information was available, it should be used in the model. If such
were not the case, national data would be selected and used for all regions. However,
for most activities, regional or Canadian emission coecients still need to be estimated. The only information that was Canadian based was the soil carbon sequestration coecients, which were obtained using the Century model calibrated for the
region speci®c situations8. In all other cases, the model used the IPCC default values
as emission coecients.
The third sub-model of CEEMA is the Greenhouse Gas Emissions Sub-Model
(GHGEM). This model had the same level of disaggregation as the CRAM for
regional, enterprise and technology of production. It used the information on emission coecients (in sub-model 2) and the level of primary production activities from
the resource allocation model to estimate GHG emissions.
In addition to GHG emissions induced by crop and livestock production, this submodel included agroecosystem-based emissions. Total land base on farms was divided into two types: cultivated and uncultivated. The cultivated land base was handled through crop production levels in the resource allocation sub-model. The latter
category of land use included two types: (1) area under water (waterlogged) which
results in emissions of methane; and (2) land covered by shelterbelts and other trees
including agro-forestry, which results in the temporary sequestration of carbon. The
term temporary is used to denote that the carbon sequestered by the trees is released
into the atmosphere at the point of its ®nal use Ð either burnt as fuel, or left as a
waste product (either in the municipal waste sites or individual areas). In both cases,
this generates emissions of either carbon dioxide or methane into the atmosphere.
In addition to the three criteria for disaggregation, the GHGEM was further disaggregated with respect to processes associated with GHG emissions and the major
GHGs. For each of the three GHGs, various processes associated with GHG
emissions were grouped into eight modules, as shown in Fig. 2. These modules
depict all backward and forward linkages of primary agricultural production. In
total, 39 dierent processes in the agricultural and agri-food sector were hypothesized to be responsible for emissions from the sector. A complete list is presented in
Table A3.
3.3. Model Requirements
The model required three major components: (1) development of baseline data for
the 1990 and 2010 scenarios; (2) calibration of the resource allocation sub-model
for the baseline situation(s); and (3) incorporation of emission coecients for the
GHG emissions sub-model. In this study two baseline periods were used: 1990 and
2010. Their selection was based on the consideration that both of these are used for
8
The Century model was developed by Parton et al. (1987). This model has been extensively used for
various parts of Canada. For details on the Century model based results, see Desjardins et al. (unpublished).
S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
153
Fig. 2. Greenhouse gas emissions model for the Canadian Agriculture and Agri-Food Sector.
measuring commitments under the Kyoto Protocol. The 1990 baseline is the basis
against which to measure the required reduction in GHG emissions, while the 2010
BAU baseline is needed for measuring the performance of mitigation eorts by
Canada.
The 1990 baseline data were obtained from the 1991 Census of Agriculture (Statistics Canada, 1993). The 2010 BAU baseline was developed using results for
AAFC's Medium Term Policy Baseline projections9 to 2007, further extended to the
9
The Medium Term Baseline (MTB) is projected to the year 2007. The extension to the year 2010 was
simply a linear extrapolation. Details on the MTB projections are in Agriculture Canada (1998).
154
S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
year 2010. The. calibration of the CRAM involved matching the baseline data for
the two periods10 and was programmed using GAMS (see http://www.gams.com/
contacti.htm).
Estimation of the GHGEM was based on techniques referred to in Desjardins and
Riznek (2000). Emissions were calculated for three modules: crop production, livestock production, and the indirect agroecosystem. For the remaining modules,
information was collected either from IPCC (Houghton et al., 1997) or Environment
Canada (1997). Since energy use is the main source of emissions for non-primary
agricultural activities, energy use data were obtained from the ICE and/or CIPEC
Surveys11.
4. Results
4.1. Baseline (1990) emissions of GHG from agriculture
The Canadian AAFS contributes to GHG buildup through emissions of all three
major gases Ð carbon dioxide, methane and nitrous oxide. However, for carbon
dioxide, the sector is a minor contributor at the national level, which is not the case
with the other two gases. For nitrous oxide emissions, AAFS's share is 59% of the
total Canadian GHG emissions, and as such is the largest single source of such
emissions (Table 1). For methane, agriculture is also a major contributor, since 36%
of the total Canadian emissions are from the AAFS. Since agriculture is not a major
user of energy, its share of total Canadian emissions of carbon dioxide is very small.
The level of GHG emissions from the AAFS is either reported by the weight of
each gas emitted, or by the weight in carbon dioxide equivalent of each gas. The
latter is based on the respective 100-year global warming potential.12 In absolute
quantities, the major gas that is emitted from the agroecosystem is carbon dioxide.
The emissions are substantially larger than for methane and nitrous oxide (Table 1).
Although the other two gases are emitted in relatively small quantities (Fig. 3a), a
more realistic picture of the distribution of major GHG emissions is obtained after
these emissions are converted into CO2-Eq. Here, as shown in Fig. 3b, nitrous oxide
is the major GHG emitted by agriculture, followed by carbon dioxide, and methane.
A little over a third of the total emissions (37%) from the AAFS are in the form of
nitrous oxide. The main sources of such emissions are from fertilizer use, biological
®xation, crop residues and from manure handling systems and soil applications.
Application of manure and fertilizer to soils also give rise to indirect sources of
nitrous oxide. Much of the carbon dioxide emissions at the primary production level
10
More details on the CRAM are provided in Horner et al. (1992).
Details on these can be obtained from Statistics Canada (1997) and Natural Resources Canada
(1997).
12
The 100-year global warming potential for methane is estimated at 21 times that of CO2, whereas for
nitrous oxide, the global warming potential is 310 times that of CO2. For details see, Environment Canada
(1997).
11
155
S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
Table 1
Estimated emissions of greenhouse gases, by individual gas, Canada, 1990a
Source of emissions
Level of emissions in kilotonnes
Carbon dioxide
Crop production (including loss of soil carbon)
Livestock production
Indirect crop and livestock production
On-farm fuel use (farm machinery, transportation,
and stationary combustion)
Soil carbon sequestrationb
Agroecosystemb
Methane
Nitrous oxide
6033
0
0
7657
0
977
0
1
36
32
31
1
ÿ10
ÿ643
0
17
0
0
Total primary agriculture
13,037
994
100
Farm input manufacturing
O-farm transportation and storage
Food processing
10,771
1179
4488
271
www.elsevier.com/locate/agsy
Prioritizing greenhouse gas emission mitigation
measures for agriculture
S.N. Kulshreshtha a,*, B. Junkins b, R. Desjardins c
a
Department of Agricultural Economics, University of Saskatchewan, Saskatoon, SK, S7N 5A7, Canada
b
Policy Branch, Agriculture and Agri-food Canada, Ottawa, ON, Canada
c
Research Branch, Agriculture and Agri-food Canada, Ottawa, ON, Canada
Received 31 March 2000; received in revised form 10 August 2000; accepted 14 August 2000
Abstract
Since the signing of the Kyoto Protocol, a major eort has been launched in Canada to
identify cost-eective measures to reduce greenhouse gas (GHG) emissions. Agriculture is an
important contributor of methane and nitrous oxide in Canada. Over one-third of methane
and almost four-®fths of nitrous oxide emissions are from agriculture either directly or indirectly. By 2010 primary agricultural production is expected to generate about 67 megatonne (in
carbon dioxide equivalent), which increases to 97 megatonnes if all activities related to agricultural production are considered. Based on a systems approach, nutrient management was
selected as a possible scenario for mitigation. Estimated results indicate that this could lead to
a reduction of 0.9 megatonnes of GHG emissions at the primary agricultural production level,
and 1.2 megatonnes if the total agriculture and food sectors are included. Compared to the
direct emissions (from fertilizer rate and timing of application), the systems approach suggests
up to a doubling (from 0.4 to 0.92 Mt) of this reduction potential at the primary production
level. If one were to include emissions from the entire agriculture and agri-food system,
potential of up to tripling (from 0.4 to 1.23 Mt) the reduction of GHG can be achieved. The
need of a systems approach in prioritizing measures to reduce GHG emissions is supported by
this study. # 2001 Elsevier Science Ltd. All rights reserved.
Keywords: Greenhouse gas emission; Agriculture; Mitigation measures; Prioritizing; Canada
* Corresponding author. Tel.: +1-306-966-4014; fax: +1-306-966-8413.
E-mail address: kulshres@duke.usask.ca (S.N. Kulshreshtha).
0308-521X/01/$ - see front matter # 2001 Elsevier Science Ltd. All rights reserved.
PII: S0308-521X(00)00041-X
146
S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
1. Introduction
1.1. Background
Behind many of the natural disasters that have occurred during the 1990s lurks the
specter of human-induced global climate change. Armed with this information along
with other global changes as background, in 1992, some 176 countries met in Rio de
Janeiro to sign the UN Framework Convention on Climate Change. The major
objective of this Convention was to start the process of stabilizing the greenhouse
gas (GHG) concentrations in the atmosphere at a level below which they would not
contribute to climate change. Such reductions were viewed as instrumental in
achieving sustainable economic activity world wide. The Convention was supplemented by the Kyoto Protocol, which was a result of the Conference of the Parties,
which met in Kyoto, Japan, in December of 1997. At this meeting, further commitments in the form of targets for reducing GHG emissions were agreed upon. Under
this Kyoto Protocol, Canada signed an agreement to reduce its GHG emissions in
2010 (or during the period 2008±2012) to a level that is 6% lower than the 1990
level. As a baseline, these future emissions are projected under a non-intervention1
type of economic policy regime, called ``Business as usual'' (BAU).
Meeting the commitments made under the Kyoto Protocol requires careful planning, prioritization, and eventual implementation of mitigation measures and policies. In response to these commitments, the Government of Canada has instituted a
process of developing a ``National Implementation Strategy'' for mitigating GHG
emissions. Under this Program, a sum of $150 million has been allocated over 3
years for activities devoted to four themes: Technology Early Action Measures;
Science, Impacts and Adaptation; Foundation Analysis, and, Public Outreach2.
Under the Foundation Analysis theme, the Government has established 16 Issue
Tables, one of which deals with the agriculture and agri-food sector.
The Agriculture and Agri-Food Climate Change Table (henceforth referred to as
the Table) was set up to develop recommendations on various mitigation strategies
and govemment/industry policies (and programs) that would lead to a reduction in
the emissions of GHGs from agriculture, and thus help Canada meet its commitment under the Kyoto Protocol. Developing recommendations for various mitigation strategies that can be undertaken by producers requires information on several
fronts. These include, although are not necessarily limited to, the following:
1. development of emission estimates from agricultural production for the two
base periods Ð 1990 and 2010 under the BAU scenario;
2. identi®cation of mitigation strategies that can be implemented at the farm level
which would lead to reductions in agriculturally induced GHG emissions; and
1
This refers to a set of conditions where no speci®c measure to reduce emissions of GHG is undertaken
by the country.
2
The allocation of resources for these themes is as follows: Technology Early Action Measure Ð $6
million; Science, Impacts and Adaptation Ð $15 million; Foundation Analysis Ð $34 million; and Public
Outreach Ð $30 million.
S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
147
3. a comparative analysis of the eectiveness of each strategy and/or measures in
reducing emissions of GHGs from the agriculture and agri-food sector.
In addition, the Table was also expected to evaluate each mitigation strategy in
terms of broad socioeconomic, health, and environmental impacts, as well as to
assess various policy measures that may be required to ensure the adoption of the
recommended mitigation strategy3.
1.2. Need for the study
In order to make recommendations for the selected mitigation strategies for GHG
emission reduction, two types of tools are required: (1) tools for developing estimates of GHG emissions from the Agriculture and Agri-Food Sector (AAFS) in
Canada at both national and regional levels; and (2) tools for testing the eectiveness of selected mitigation strategies. The ®rst set of tools requires information on
the manner in which the adopted strategy would reduce GHG emissions in various
regions of Canada. Such information could be obtained from scienti®c experiments
under the assumed rate of adoption of the selected strategy.
In determining the emissions of GHGs from agriculture, two other considerations
are important.
1. Farm level activities, although a major contributor of GHG emissions from
agriculture, are related to other economic activities in the region as well as
those outside the region. Two types of linkages that exist are: backward linkages of the agriculture sector, and forward linkages. Backward linkages are
established between sectors when agriculture purchases its input needs from
other sectors. The forward linkages, in turn, are established between agriculture and those sectors that use its products for further value-added activities. Let us illustrate the interrelationships between mitigation strategies and
forward and backward linkages of agriculture. Let us assume that the selected
mitigation measure is the adoption of proper soil nutrient management on
farms. Such an adoption will lead to a change in the amount of nutrients added
to various crops in various regions of Canada. Depending upon the nature of
change, fertilizer input demand by farms would change. If the adjustment
aects yields, it may also aect the relative pro®tability of various crops and
may lead to a dierent production mix in dierent regions. Changes in the crop
mix may also lead to impacts on livestock production. Depending upon the
magnitude of such changes, this may further aect the competitiveness of
processing industries, and thereby aect emissions from the food processing
sub-sector. Such changes may be instrumental in bringing forth changes in
regional trade, and may aect production of various agricultural products
in other regions of Canada. Each of these changes would trigger an adjustment
of GHG emissions in Canada.
3
This analysis was considered outside the scope of the present study and, therefore, not reported here.
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2. Although most farmland is used for commercial agricultural pursuits, there are
other land use activities from the farm unit that have implications for GHG
emissions. This requires an examination of GHG emissions in a `whole farm'
context.
The above two considerations raise the central question: ``How should the emissions from agriculture be measured, particularly in the context of prioritizing various mitigation strategies in terms of their eectiveness for reducing GHG
emissions?'' In this study, the suggested framework is that of the entire agriculture
and agri-food system within a whole farm context. Adoption of a mitigation strategy by a producer may lead to other changes on the farm itself or at the regional
level. Therefore, in addition to developing appropriate estimates of GHG emissions
from agriculture, in the context of prioritizing various mitigation strategies, one
should also resolve the issue related to changes in other farm and/or regional level
activities resulting from the adoption of a given mitigation strategy.
2. Objectives and scope of the study
The major objective of this study is to develop a methodology for the estimation
of GHG emissions from Canadian agriculture using a combined agriculture and
agri-food sector approach and the whole farm context. This model is then used to
illustrate the changes in GHG emissions for various mitigation strategies. Results
are compared against model results where such linkages and whole farm context are
not considered.
The objectives of the study are accomplished through the following sub-objectives:
1. to develop a conceptual model of accounting for GHG emissions from the
AAFS that is appropriate in the context of developing recommendations for
the National Implementation Strategy for Canada on Climate Change;
2. to estimate various components of the conceptualized model for two base
periods Ð 1990, and 2010 under the BAU scenario;
3. to illustrate the estimated changes in emissions levels from the 2010 BAU case
for a simple scenario involving fertilizer use in various regions of Canada; and
4. to draw implications for using an appropriate methodology for prioritizing
GHG emission mitigation strategies for the Canadian AAFS.
The results presented here are part of the broader study of economic impacts of
GHG mitigation strategies under consideration by the Table4. However, discussion
in this study is limited to the examination of the GHG reduction potential for a
selected mitigation scenario. Results of all possible scenarios that can be considered
to meet Canadian agriculture's intended commitment under the Kyoto Protocol
are not reported here, since this requires another study. Other impacts, such as
4
The broader study is prepared by the Agriculture and Agri-Food Climate Change Table. Technical
aspects of various mitigation strategies are reported by Junkins et al. (2000).
S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
149
economic development impacts, ®scal impacts on various levels of governments, and
regional development are also not included.
3. Model
3.1. Considerations involved
Proper determination of GHG emissions for the AAFS can be guided by three
considerations: (1) the need to include all anthropogenic activities of the Canadian
AAFS that lead to GHG emissions; (2) the need to include all other farmland uses
besides agricultural pursuits, which is consistent with the `whole farm' approach;
and (3) the need for consistency with the Intergovernmental Panel for Climate
Change (IPCC) and Canada's Greenhouse Gas Inventory in accounting for and the
aggregation of GHG emissions from various economic activities.
The ®rst consideration led to relating agricultural production to all major forward
and backward linkages in the region. Two types of forward linkages were identi®ed
for agriculture: (1) those within primary agriculture; and (2) those beyond primary
agriculture. The former includes linkages between feed grain production and livestock
production, while the latter includes links with transportation of agricultural products beyond the farm gate (excluding that undertaken by producers), and processing
activities induced by the availability of raw material for value added activities.
The second aspect of accounting for all agricultural GHG emissions required the
inclusion of emissions from all farmlands and related activities within the agroecosystem level. Producers, in addition to cultivated lands, have uncultivated lands on
farms. Some of these are waterlogged (farm potholes or wetlands), some are woodlots (bushes and other vegetation), while others are forested. These land use activities either emit GHGs or sequester carbon.
The need for the third consideration was of paramount importance in the context
of the Kyoto Protocol, since measurement of success is done in a framework prescribed by the IPCC (Houghton et al., 1997). The recommendations of the IPCC
include a well-de®ned accounting framework for reporting inventories of GHG
emissions. Details of this framework are provided in Houghton et al. (1997). Two
stipulations in these guidelines are signi®cant for this study: (1) this framework
suggested that accounting for emissions from non-energy sources be done separately
from those from the energy-based inputs; and (2) soils as sinks of carbon are not
recognized under the Protocol at this time. Thus, under this framework, agricultural
soils as emitters of carbon dioxide (through the loss of soil carbon) are included in
Canada's inventory of agricultural emissions, but when soils reach an equilibrium
and beyond (i.e. becoming net sinks of carbon), carbon sequestration activities are
not included5.
5
At the time of writing this paper, two activities were underway: (1) the IPCC has just completed a
special report on the soils as sinks; and (2) negotiations are currently underway at various Conference of
the Parties to have sinks recognized as a part of the reduction targets under the Kyoto Protocol.
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In order to maintain consistency with the IPCC guidelines, as well as to conduct
the analysis incorporating the entire AAFS and the whole farm concept, estimated
emissions from on-farm energy use and soil carbon were kept separate. This led to
the model being more disaggregated in nature so as to allow for the accounting of
GHG emissions from agriculture under the IPCC framework, as well as providing a
more realistic picture of the total agricultural and agriculturally induced emissions
for Canada.
3.2. Overview of the model
The model used in the study was designed to estimate emissions of three main
GHGs associated with agriculture Ð carbon dioxide, methane, and nitrous oxide.
This distinction was necessitated by the fact that each of these gases have a dierent
global warming potential6. In order to ensure that the estimated emissions could be
used for the purposes of examining mitigation strategies for meeting the Kyoto
Protocol commitment, the model combined economic decision-making under a
given set of physical and economic environments with emissions of GHGs. The
resulting model was named the Canadian Economic and Emissions Model for
Agriculture (CEEMA). The CEEMA being used in this study is a second generation
model. The ®rst generation model CEEMA Version 1.0 is described in Kulsbreshtha
et al. (1999). An overview of the model used in this study is shown in Fig. 1.
The CEEMA is organized into three sub-models (or blocks): resource allocation,
science of GHG emissions, and estimation of total GHG emissions. The ®rst submodel depicts regional resource allocations for crops and livestock, and is named the
Canadian Regional Agriculture Sub-Model (CRAM). This sub-model was disaggregated using three criteria:
1. geographical location of agricultural activity;
2. type of enterprise (crop type or livestock type); and
3. technology of production (based on tillage systems, and crop rotations).
Agricultural activities were modeled on a provincial basis for all livestock production activities and for crop activities in regions outside the Prairies. However, crop
production in each of the three Prairie provinces was disaggregated on a sub-provincial level based on Census of Agriculture regions. Details on the number of
regions for the crop and livestock production blocks are shown in Table A1 in the
Appendix. Using the second criteria, all important crops were included in the model,
as shown in Table A2. Various crop production regions had dierent mixtures of
crops. Forages are important to the model since they provide an important linkage
between crop and livestock production. Major livestock production included in the
6
The term global warming potential refers to the relative contribution of each of these gases towards
radiative forcing, which is responsible for the climate change phenomenon. According to Environment
Canada (1997), these potentials are measured relative to carbon dioxide. Resulting values are called
``Carbon Dioxide Equivalent''.
S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
151
Fig. 1. Schematic of the components of CEEMA.
study were: beef cattle, dairy cattle, hogs, poultry, and sheep and lambs7. Using the
third criterion Ð technology of production, various crops in the three prairie provinces and sub-regions were modeled using summerfallow and stubble (continuous
cropping) rotations. Furthermore, wherever relevant, each of these production
practices were speci®ed using one of three tillage systems: conventional tillage,
minimum tillage, and no or zero tillage.
The second sub-model in CEEMA was the block where information on the science of GHG emissions was collected. This led to the development of emission
coecients for the various crop and livestock activities speci®ed in the resource
7
Sheep and lambs were included in the GHG emissions sub-model. These were exogenous to the
resource allocation sub-model.
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allocation model. The order of priority in selecting a particular emission coecient
should be regional, national (Canadian), and IPCC default values. In other words, if
region-speci®c information was available, it should be used in the model. If such
were not the case, national data would be selected and used for all regions. However,
for most activities, regional or Canadian emission coecients still need to be estimated. The only information that was Canadian based was the soil carbon sequestration coecients, which were obtained using the Century model calibrated for the
region speci®c situations8. In all other cases, the model used the IPCC default values
as emission coecients.
The third sub-model of CEEMA is the Greenhouse Gas Emissions Sub-Model
(GHGEM). This model had the same level of disaggregation as the CRAM for
regional, enterprise and technology of production. It used the information on emission coecients (in sub-model 2) and the level of primary production activities from
the resource allocation model to estimate GHG emissions.
In addition to GHG emissions induced by crop and livestock production, this submodel included agroecosystem-based emissions. Total land base on farms was divided into two types: cultivated and uncultivated. The cultivated land base was handled through crop production levels in the resource allocation sub-model. The latter
category of land use included two types: (1) area under water (waterlogged) which
results in emissions of methane; and (2) land covered by shelterbelts and other trees
including agro-forestry, which results in the temporary sequestration of carbon. The
term temporary is used to denote that the carbon sequestered by the trees is released
into the atmosphere at the point of its ®nal use Ð either burnt as fuel, or left as a
waste product (either in the municipal waste sites or individual areas). In both cases,
this generates emissions of either carbon dioxide or methane into the atmosphere.
In addition to the three criteria for disaggregation, the GHGEM was further disaggregated with respect to processes associated with GHG emissions and the major
GHGs. For each of the three GHGs, various processes associated with GHG
emissions were grouped into eight modules, as shown in Fig. 2. These modules
depict all backward and forward linkages of primary agricultural production. In
total, 39 dierent processes in the agricultural and agri-food sector were hypothesized to be responsible for emissions from the sector. A complete list is presented in
Table A3.
3.3. Model Requirements
The model required three major components: (1) development of baseline data for
the 1990 and 2010 scenarios; (2) calibration of the resource allocation sub-model
for the baseline situation(s); and (3) incorporation of emission coecients for the
GHG emissions sub-model. In this study two baseline periods were used: 1990 and
2010. Their selection was based on the consideration that both of these are used for
8
The Century model was developed by Parton et al. (1987). This model has been extensively used for
various parts of Canada. For details on the Century model based results, see Desjardins et al. (unpublished).
S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
153
Fig. 2. Greenhouse gas emissions model for the Canadian Agriculture and Agri-Food Sector.
measuring commitments under the Kyoto Protocol. The 1990 baseline is the basis
against which to measure the required reduction in GHG emissions, while the 2010
BAU baseline is needed for measuring the performance of mitigation eorts by
Canada.
The 1990 baseline data were obtained from the 1991 Census of Agriculture (Statistics Canada, 1993). The 2010 BAU baseline was developed using results for
AAFC's Medium Term Policy Baseline projections9 to 2007, further extended to the
9
The Medium Term Baseline (MTB) is projected to the year 2007. The extension to the year 2010 was
simply a linear extrapolation. Details on the MTB projections are in Agriculture Canada (1998).
154
S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
year 2010. The. calibration of the CRAM involved matching the baseline data for
the two periods10 and was programmed using GAMS (see http://www.gams.com/
contacti.htm).
Estimation of the GHGEM was based on techniques referred to in Desjardins and
Riznek (2000). Emissions were calculated for three modules: crop production, livestock production, and the indirect agroecosystem. For the remaining modules,
information was collected either from IPCC (Houghton et al., 1997) or Environment
Canada (1997). Since energy use is the main source of emissions for non-primary
agricultural activities, energy use data were obtained from the ICE and/or CIPEC
Surveys11.
4. Results
4.1. Baseline (1990) emissions of GHG from agriculture
The Canadian AAFS contributes to GHG buildup through emissions of all three
major gases Ð carbon dioxide, methane and nitrous oxide. However, for carbon
dioxide, the sector is a minor contributor at the national level, which is not the case
with the other two gases. For nitrous oxide emissions, AAFS's share is 59% of the
total Canadian GHG emissions, and as such is the largest single source of such
emissions (Table 1). For methane, agriculture is also a major contributor, since 36%
of the total Canadian emissions are from the AAFS. Since agriculture is not a major
user of energy, its share of total Canadian emissions of carbon dioxide is very small.
The level of GHG emissions from the AAFS is either reported by the weight of
each gas emitted, or by the weight in carbon dioxide equivalent of each gas. The
latter is based on the respective 100-year global warming potential.12 In absolute
quantities, the major gas that is emitted from the agroecosystem is carbon dioxide.
The emissions are substantially larger than for methane and nitrous oxide (Table 1).
Although the other two gases are emitted in relatively small quantities (Fig. 3a), a
more realistic picture of the distribution of major GHG emissions is obtained after
these emissions are converted into CO2-Eq. Here, as shown in Fig. 3b, nitrous oxide
is the major GHG emitted by agriculture, followed by carbon dioxide, and methane.
A little over a third of the total emissions (37%) from the AAFS are in the form of
nitrous oxide. The main sources of such emissions are from fertilizer use, biological
®xation, crop residues and from manure handling systems and soil applications.
Application of manure and fertilizer to soils also give rise to indirect sources of
nitrous oxide. Much of the carbon dioxide emissions at the primary production level
10
More details on the CRAM are provided in Horner et al. (1992).
Details on these can be obtained from Statistics Canada (1997) and Natural Resources Canada
(1997).
12
The 100-year global warming potential for methane is estimated at 21 times that of CO2, whereas for
nitrous oxide, the global warming potential is 310 times that of CO2. For details see, Environment Canada
(1997).
11
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S.N. Kulshreshtha et al. / Agricultural Systems 66 (2000) 145±166
Table 1
Estimated emissions of greenhouse gases, by individual gas, Canada, 1990a
Source of emissions
Level of emissions in kilotonnes
Carbon dioxide
Crop production (including loss of soil carbon)
Livestock production
Indirect crop and livestock production
On-farm fuel use (farm machinery, transportation,
and stationary combustion)
Soil carbon sequestrationb
Agroecosystemb
Methane
Nitrous oxide
6033
0
0
7657
0
977
0
1
36
32
31
1
ÿ10
ÿ643
0
17
0
0
Total primary agriculture
13,037
994
100
Farm input manufacturing
O-farm transportation and storage
Food processing
10,771
1179
4488
271