Agricultural Greenhouse Gas Indicator
The Agricultural Greenhouse Gas (GHG) Budget Indicator tracks the greenhouse gas emissions (carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) emissions) associated with Canadian agricultural activities from 1981 to 2011, and reports them in terms of carbon dioxide equivalents (CO2e).
The indicator does not attempt to capture carbon dioxide emissions from fossil fuel consumption by farm machinery, as these emissions are typically reported by the manufacturing and transportation sectors.
What are Agri-Environmental Indicators?
Agri-Environmental Indicators (AEIs) are measures of key environmental conditions, risks, and changes resulting from agriculture and of the management practices that producers use to mitigate these risks. They help explain:
- how the agriculture sector is performing,
- why it is performing as it is,
- whether that performance is satisfactory, and
- how it is likely to evolve in the future.
Agriculture and Agri-Food Canada (AAFC) has been compiling and analyzing data and reporting on AEIs since 1993, but we use data from as far back as 1981. The Agricultural Greenhouse Gases indicator is one of several national indicators being tracked by AAFC.
Overall state and trend
In 2011, the net GHG emissions (emissions minus absorption by soils) from Canadian agricultural activities, excluding fossil fuel use, amounted to 42 million tonnes of CO2 equivalents (Mt CO2e) which is equal to about 6% of Canada's overall GHG emissions. Total agricultural GHG emissions (not factoring in carbon sequestration by agricultural soils) comes to 8% of Canada's total emissions. You can view these statistics in Environment Canada's National Inventory Report 1990-2011: Greenhouse Gas Sources and Sinks in Canada - Executive Summary.
Use the interactive map below to zoom in and explore different regions. Note that all the Prairie Provinces show relatively low emissions, despite the agricultural intensity of the region. This is attributed to the uptake of beneficial management practices (BMPs) that promote the sequestration (absorption and storage) of carbon in soils, such as conversion from annual crops to perennial cover, reduced soil disturbance through no- or minimum-tillage, and the shift away from summerfallow – a practice of leaving fields bare.
In addition to exploring the 2011 emissions, click the play button to view changes over time. Since 1981, there has been a reduction in net agricultural GHG emissions by approximately 10%. Most of this reduction has taken place in the Prairie Provinces as a result of BMPs that favour soil carbon sequestration.
Interestingly, while GHG emissions as a whole have decreased since 1981, carbon dioxide equivalent gases have not all followed a similar trend. In the same period, nitrous oxide has increased by 31% and methane has increased by 2%. This confirms that the improvements in net agricultural GHG emissions have primarily come from the change in carbon dioxide emissions from agricultural soils.
Use the interactive map in Figure 2 to explore the change in net agricultural GHG emissions between 1981 and 2011. It is apparent that the reduction (i.e., negative values) is most significant in the Canadian Prairies.
Greenhouse gas performance index
The state and trend of the Greenhouse Gas Indicator can also be seen in the performance index below.
Description - Figure 3
In 2011, the state of the environment, as it relates to GHG emissions resulting from farming activities in Canada, was in the "Desired" category. The index illustrates a relatively constant trend since 1981, with emissions caused by increased production being largely countered by improvements in production efficiency and by enhanced carbon storage in soils due to tillage reductions. Since 2006, the decline in beef production has led to a decrease in methane emissions, resulting in a slight index value increase – from 79 back to the 1981 value of 81.
The index tends to aggregate and generalize trends. In particular, it is not capturing significant reductions within the lowest and highest emission classes, which have a decline in annual greenhouse gas emissions of nearly 5 Mt CO2e, or about 10% since 1981.
How performance indices are calculated
- Trend 1 – Prairie farmland, significant carbon dioxide sink
- Trend 2 – Nitrous oxide increase attributed to nitrogen fertilizer increase
- Trend 3 – Declining animal populations and methane emissions
- Trend 4 - Eastern Canada farming changes result in increased net GHG emissions
This section highlights a few other trends of interest. In some cases, these are occurring in certain regions and in others they are affecting certain sectors, such as the beef or dairy industries. This is not an exhaustive list; additional findings can be found in the full publication: Environmental Sustainability of Canadian Agriculture, Agri-Environmental Indicator Report Series - Report #4
Trend 1 – Prairie farmland, significant carbon dioxide sink
The primary reason for declining net agricultural GHG emissions in Canada is due to the change in carbon dioxide emissions from agricultural soils, which went from being a minor source (emitting CO2) of about 1.1 Mt CO2e in 1981 to a sink (indicating absorption of carbon) of about -11.9 Mt CO2e in 2011. Agricultural soils, particularly in the Prairie Provinces of Canada, are now a significant sink for carbon dioxide. Figure 4 demonstrates how this change in status from source to sink in the Prairies (Alberta, Saskatchewan and Manitoba) has changed the trend in net emissions, despite the increases in nitrous oxide and methane emissions.
Description - Figure 4
|Greenhouse Gas (in Mts carbon dioxide equivalents (CO2e)||1981||1986||1991||1996||2001||2006||2011|
|Nitrous Oxide (N2O)||13.93||16.04||16.32||20.52||20.05||20.83||21.86|
|Soil carbon (Soil CO2)||-1.58||-3.46||-4.28||-7.68||-11.58||-14.78||-15.20|
|Net total (All greenhouse gases combined)||22.20||21.68||22.24||25.76||22.95||21.52||19.54|
Reasons for trend 1
This reduction is primarily due to the widespread adoption of BMPs, such as the reduction in tillage intensity, the reduction in summerfallow – a practice of leaving fields bare – and the conversion of annual to perennial cropping systems. These practices improve soil health by encouraging the build-up of organic soil carbon.
Trend 2 – Nitrous oxide increase attributed to nitrogen fertilizer increase
The 31% increase in national agricultural nitrous oxide emissions is primarily due to the growth of nitrogen fertilizer application. You can see this trend in Figure 5.
Description - Figure 5
Reasons for trend 2
In 1981, national consumption was about 0.94 million tonnes of nitrogen, which more than doubled to 2.0 million tonnes in 2011. This increase has not been evenly distributed across the country; consumption in Western Canada has increased by more than 150%, whereas consumption in Eastern Canada has only increased by 22%. The dramatic increase in the use of nitrogen fertilizer has helped to set repeated crop production records in Canada, but as a consequence has also increased nitrous oxide emissions.
Trend 3 – Declining animal populations and methane emissions
Agricultural methane emissions in Canada increased by 2% between 1981 and 2011, but decreased substantially between 2006 and 2011 (see Figure 6).
Description - Figure 6
Reasons for trend 3
The majority (88%) of agricultural methane emissions comes from beef and dairy cattle and the remainder comes from manure management.
Between 1981 and 2011, the dairy cow population in Canada steadily declined from about 1.8 to 1 million head. This reduction was made without affecting total milk production in Canada thanks to productivity gains in milk production per cow.
The beef cattle population increased between 1986 and 2006, before significantly decreasing between 2006 and 2011. There are a variety of reasons for this decline, including:
- holdover effects from the bovine spongiform encephalopathy (BSE) crisis in 2003–2004,
- a high Canadian dollar that has made exports to the USA more expensive, and
- country-of-origin labelling that may discourage consumers in other nations from consuming Canadian beef.
These and other factors have combined to create a challenging economic environment for Canadian cattle producers. This has resulted in a reduction in the beef herd of about 2 million head, equaling a 14% decline since 2006.
While they have increased by 18% since 1981, the number of swine has also declined since 2006. Swine do not produce as much methane as cattle through enteric fermentation. However, their manure is high in methane, and since it is widely used in liquid manure management systems, swine manure is a contributing factor to overall methane emissions. Poultry production has also plateaued since 2001.
Trend 4 - Eastern Canada farming changes result in increased net GHG emissions
Between 1981 and 2011, Eastern Canada, large areas of southwestern Ontario, the St. Lawrence River Valley, and the St. John River Valley all experienced a net increase in agricultural GHG emissions.
Using the interactive map in Figure 7, move the vertical bar from side to side to see the net increase in GHG emissions over last 30 years.
Reasons for trend 4
Dairy herds in these regions have declined, prompting the conversion of perennial forages to annual crops that has resulted in increased soil carbon dioxide emissions. There has also been an increase in nitrogen-demanding crops, such as corn.
Why this indicator matters
Greenhouse gas emissions have been conclusively linked to climate change, and continued emissions may worsen this problem for future generations.
Agriculture has the potential to mitigate by:
- Implementing BMPs that either reduce emissions or encourage the capture and storage of carbon in agricultural soils, and
- Reducing the intensity of emissions on a per-unit production basis, whereby technological and management solutions are used to lower the amount of emissions it takes to produce a unit of product, such as meat or milk.
Beneficial Management Practices
In the Prairies especially, producers can increase their land's carbon storage capacity by reducing summerfallow and tillage intensity and by converting annual crops to perennial cropping systems. Other innovations, such as dietary management to lower methane emissions or manure management to reduce nitrous oxide emissions, are encouraged. Canada is one of the founding members of the Global Research Alliance (GRA) on Agricultural Greenhouse Gases, an international network of more than 30 member-countries, devoted to collaboration in agricultural research on greenhouse gas mitigation and BMPs for farmers in Canada and around the world.
In 2010, AAFC launched the Agricultural Greenhouse Gases Program (AGGP) – a five-year, $27-million program, to encourage ground-breaking research to provide Canadian farmers with technologies to manage their land and livestock in a way that will mitigate GHG emissions. This program has since been extended until 2021.
Reducing emissions intensity
Due to the need to produce an increasing amount of food to satisfy growing Canadian and global demand, combined with the limitations of existing agricultural GHG mitigation measures, it is important to acknowledge that reducing net Canadian agricultural GHG emissions in the future is likely to be a significant challenge. Therefore, a more realistic expectation of the agricultural sector may be to achieve declining intensity of emissions for a given product over time. For this reason, AAFC is in the process of developing an Emission Intensity Metric which represents the combined GHG emissions associated with the growth, transportation and processing of one unit of a given product, for instance a tonne of grain or a kilogram of beef.
Additionally, AAFC has developed Holos, a model and software program that estimates GHG emissions based on information entered for individual farms.
How this indicator relates to trade
Reducing GHG emissions is a global priority and as such, nations and multi-national corporations have implemented policies that tend to favour products and services that emit less per unit product. For example, in 2012, Canada exported roughly 30,000 tonnes of canola oil to the European Union (valued at over $34 million), which was destined for consumption as biofuel for use in transportation. The Canadian producers of the canola oil had to demonstrate that the GHG emissions from the production and processing of their canola met or exceeded the European Union’s GHG reduction threshold. The values of the GHG indicator for Canadian agriculture were used to demonstrate that the Canadian canola exceeded this threshold, enabling access to the European market by Canadian canola producers.
Carbon Dioxide Equivalent
Carbon dioxide equivalent (CO2e) is a measure for describing how much global warming a given type and amount of GHG may cause, using the functionally equivalent amount or concentration of carbon dioxide as the reference. A CO2e is calculated by multiplying the amount of gas by its associated global warming potential. The global warming potential accounts for the unique ability of each gas to absorb radiation and for its residence time in the atmosphere.
The global warming potentials below are based on the Intergovernmental Panel on Climate Change (IPCC) Second Assessment Report, as these are the calculations used in determining the GHG indicator findings for 2011, reported above.
|Greenhouse Gas||Global Warming Potential|
This means that 1 kilogram of methane has 21 times the impact of carbon dioxide, and 1 kilogram of nitrous oxide has 310 times the impact of carbon dioxide on global warming.
The global warming potential values have since been revised and reported in the Fourth Assessment report. Recalculating the indicator with these values will result in a change in the magnitude of the emissions, but will not affect the trend in the emissions. The Environment Canada website has more information on global warming potentials.
How performance indices are calculated
The agri-environmental performance index shows environmental performance state and trends over time, based on weighting the percentage of agricultural land in each indicator class, such that the index ranges from 0 (all land in the most undesirable category) to 100 (all land in the most desirable category). The equation is simply "(% in poor class multiplied by .25) plus (% in moderate class multiplied by .5) plus (% in good class multiplied by .75) plus (% in desired class)." As the percentage of land in the "at risk" class is multiplied by zero, it is not included in the algorithm.
The table below shows the index classes. The index uses the same five-colour scheme as the indicator maps whereby dark green represents a desirable or healthy state and red represents least desirable or least healthy.
The index tends to aggregate and generalize trends and so should be viewed as a policy tool to give a general overview of state and trend over time.
- The Soil Organic Matter Indicator tracks the health of Canadian agricultural soils as it relates to soil carbon content and soil carbon exchange.
- The Ammonia Indicator estimates agricultural ammonia emissions.
- The Particulate Matter Indicator estimates the contribution to primary particulate matter from agricultural operations
Additional resources and downloads
- For detailed information on this indicator please see the publication entitled Environmental Sustainability of Canadian Agriculture, Agri-Environmental Indicator Report Series - Report #4.
- Discover and download geospatial data related to this and other indicators.
- National Greenhouse Gas Emissions – Environment Canada Indicator
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