Greenhouse gas emissions

Note: Data are presented as rounded figures.

Download data file (Excel/CSV; 1.33 kB)

Note: Data are presented as rounded figures.

Download data file (Excel/CSV; 2.50 kB)

Greenhouse gas emissions from the oil and gas sector

Key results

• In 2021, the oil and gas sector was the largest source of GHG emissions, accounting for 28% of total national emissions with 189 megatonnes of carbon dioxide equivalent (Mt CO₂ eq) emitted
• In 2021, the sector's GHG emissions were 3% higher than in 2020
• Over the period from 1990 to 2021, the sector's GHG emissions have increased by 88%

Oil and gas sector greenhouse gas emissions, Canada, 1990 to 2021

How this indicator was calculated

Note: Conventional oil includes production from frontier, light and heavy oil fields. The Other category includes downstream oil and gas emissions (combustion and fugitive emissions from the production of refined petroleum products and the distribution of natural gas to end consumers) and oil, natural gas, and CO₂ transmission emissions (combustion and fugitive emissions from transmission, storage and delivery activities).
Source: Environment and Climate Change Canada (2023) National Inventory Report 1990-2021: Greenhouse Gas Sources and Sinks in Canada.

Between 1990 and 2021, total crude oil production more than doubled in Canada. This was mostly driven by a rapid increase in production from the oil sands, which are more GHG-intensive than conventional sources (that is, more GHGs are emitted per unit cubic meters of oil produced). This change thus had a major impact on total GHG emissions from the sector.

Over that period, GHG emissions from conventional oil production have increased by 24%, while emissions from oil sands production have increased by 463%. More than half of the increase in emissions from oil sands production over this period came from the growth of on site (in situ) production. Over the same period, production of natural gas from unconventional sources, such as those requiring the use of multi-stage fracturing techniques, also increased significantly (+55%).

Similar trends were observed between 2005 and 2020, leading to a 12% increase in GHG emissions for that period. However, over that period, emissions from natural gas and conventional oil productions decreased by 23% and 21%, respectively. Emissions from those activities have shown decreasing trends in the past decade.

Greenhouse gas emissions from the transport sector

Key results

• In 2021, the transport sector was the second largest source of GHG emissions, accounting for 22% of total national emissions with 150 megatonnes of carbon dioxide equivalent (Mt CO₂ eq) emitted
• In 2021, the sector GHG emissions were 4.8% higher than in 2020 (143 Mt CO₂ eq)
• Between 1990 and 2021, GHG emissions from the transport sector grew by 27%. The growth in emissions was mostly driven by increases from freight heavy-duty trucks and passenger light trucks

Transport sector greenhouse gas emissions, Canada, 1990 to 2021

How this indicator was calculated

Note: The Other category includes other recreational, commercial and residential uses. Categories have been adapted from the classification used in Annex 10 of the National Inventory Report. For more details, please consult the "Methods" section.
Source: Environment and Climate Change Canada (2023) National Inventory Report 1990-2021: Greenhouse Gas Sources and Sinks in Canada.

Between 1990 and 2021, part of the GHG emissions increase was due to a higher number of vehicles on the road and to changes in vehicle type used. Although total emissions from passenger transport grew by 8%, emissions from cars declined by 45%, while emissions from light trucks (including trucks, vans and sport utility vehicles) doubled. Emissions from freight travel grew by 62% between 1990 and 2021. Specifically, emissions from freight heavy-duty trucks almost doubled and emissions from other modes of freight transport increased by 13%.

Emissions from passenger and freight transport are influenced by a variety of factors, including population and economic growth, vehicle type, fuel efficiency and fuel type. Changes in the mix of vehicle type used, such as the increasing preference of passenger vehicle owners for light trucks rather than more fuel-efficient passenger cars, played an important role in shaping the evolution of GHG emissions.

Since 1990, the number of light trucks increased much faster than the increase of other passenger on-road vehicles. While there have been continual improvements in the fuel efficiency of both passenger cars and light trucks over the last few decades,^{Footnote 1}  these improvements were not sufficient to offset the increases in emissions due to the change in composition of the vehicle fleet.

Between 2005 and 2021, GHG emissions from the transport sector decreased by 4.3%. The reduction in emissions was mostly driven by decreases from passenger cars. However, it should be noted that GHG emissions increased by 13 Mt CO₂ eq. (+9%) between 2005 and 2019 before being completely offset by a 27 Mt CO₂ eq. reduction between 2019 and 2020. This emission reduction is the highest annual decrease since 1990 and was likely influenced by the impacts of the COVID-19 pandemic on the transport sector (fewer kilometres driven and a decrease in air traffic). Between 2020 and 2021, emissions from the transport sector increased by 7 Mt CO₂ eq. following recovery of economic activities and the resumption of travel that had been limited by the pandemic.

Greenhouse gas emissions from the agriculture sector

Greenhouse gas emissions from the agriculture sector are essentially attributable to the crop production (such as cereals and oilseeds) and animal production (beef, dairy, poultry and swine) activities. Activities resulting in emissions include:

• Crop production: application of biosolids and inorganic nitrogen fertilizers, decomposition of crop residues, loss of soil organic carbon, cultivation of organic soils, indirect emissions from leaching and volatilization, field burning of agricultural residues, liming, and urea application
• Animal production: animal housing, manure storage, manure deposited by grazing animals, and application of manure to managed soils

Key results

• In 2021, the agriculture sector was the 5th largest source of GHG emissions, accounting for 10% of total national emissions with 69 megatonnes of carbon dioxide equivalent (Mt CO₂ eq) emitted
• In 2021, the sector’s GHG emissions were 2% lower than in 2020, mostly driven by a decrease in crop production emissions resulting from a hot and dry growing season
• Between 1990 and 2021, GHG emissions from the agriculture sector grew by 39%, mostly driven by an increase in emissions related to crop production 

Agriculture sector greenhouse gas emissions, Canada, 1990 to 2021

How this indicator was calculated

Source: Environment and Climate Change Canada (2023) National Inventory Report 1990-2021: Greenhouse Gas Sources and Sinks in Canada.

Between 1990 and 2021, emissions increased from 49 Mt CO₂ eq to 69 Mt CO₂ eq. This increase is primarily attributable to the doubling of crop production emissions. Even though emissions from animal production have always represented at least half of the total agriculture GHG emissions, since 2005, the proportion of emissions from the crop production has risen, reaching its highest level in 2020. The drivers of the change are a reduction of cattle populations combined with a continued increase of crop production and fertilizer use.

Between 2005 and 2021, GHG emissions from the agriculture sector showed a similar trend with an increase of 8%. 

Greenhouse gas emissions from the electricity sector

Key results

• In 2021, the electricity sector was the 6th largest source of GHG emissions, accounting for 7.7% of total national emissions with 52 megatonnes of carbon dioxide equivalent (Mt CO₂ eq) emitted
• In 2021, the sector’s GHG emissions were 4% lower than in 2020, 56% lower than in 2005, and 45% lower than in 1990

Electricity sector greenhouse gas emissions, Canada, 1990 to 2021

How this indicator was calculated

Note: The Other category includes diesel fuel oil, heavy fuel oil, light fuel oil, motor gasoline, petroleum coke, own use of primary electricity, solid wood waste, still gas and non-fuel related emissions.
Source: Environment and Climate Change Canada (2023) National Inventory Report 1990-2021: Greenhouse Gas Sources and Sinks in Canada.

Greenhouse gas emissions from combustion-based electricity generation have decreased from 95 megatonnes of carbon dioxide equivalent (Mt CO₂ eq) in 1990 to 52 Mt CO₂ eq in 2021. The growing share of electricity generated from low-GHG-emitting sources (such as hydro, other renewables and nuclear) and from fuels less GHG-intensive than coal contributed to the decline in GHG emissions from electricity generation. This transition can be observed in the fuel type shares, with coal's share of all combustion emissions having decreased from 85% in 1990 to 61% in 2021, while natural gas’ share increased from 2.9% to 33%. Similar trends were observed between 2005 and 2021, leading to a 56% decrease from 118 Mt CO₂ eq. to 52 Mt CO₂ eq.

Electricity generation technologies have various levels of GHG emission intensity (which is defined as the quantity of GHGs emitted per unit of electricity produced). Hydroelectricity and nuclear power are low emitters of GHGs, while coal-burning power plants have a higher GHG intensity than natural gas-burning power plants. The general decline in the GHG intensity of electricity generation of public electric utilities can be attributed partly to a reduction in the use of coal and increases in other power plant types.

The electricity sector’s GHG emissions were 4% lower in 2021 than in 2020. The impact of the pandemic on these emissions is uncertain since the sector's emissions have been decreasing for 13 of the last 15 years. The observed reduction can be considered similar to previous year-to-year fluctuations.

Note: ^[A] 1990 emissions data for the Northwest Territories include emissions for Nunavut, which was part of the Northwest Territories until 1999. n/a = not applicable.

Download data file (Excel/CSV; 1.52 kB)

Note: Data are presented as rounded figures. However, all calculations have been performed using unrounded data.

Download data file (Excel/CSV; 2.63 kB)

Data used to develop the emission and removal estimates presented in the National Inventory Report are drawn from published and unpublished sources from various government departments, industry sources and scientific papers.

Greenhouse gas emission estimates are provided at the national level, by economic sectors and at the provincial/territorial level. The greenhouse gas emission estimates are compiled annually and reported for the period from 1990 to 2021. Complete details of the temporal coverage for each data source used for the indicators can be found in chapters 3 through 7 of the National Inventory Report.

Preparation of the GHG emissions inventory takes almost 16 months from the end of the reporting year because of the time needed to collect, validate, calculate and interpret the data. Between November and January, emission estimates are prepared by Environment and Climate Change Canada's Pollutant Inventories and Reporting Division with input from numerous experts and scientists across Canada. From January through March, the National Inventory Report text and accompanying emissions data tables are developed. This material is reviewed by external experts and Environment and Climate Change Canada officials, and finally submitted electronically to the United Nations Framework Convention on Climate Change, by mid-April.

Since direct measurement of emissions from all sources is not possible, the United Nations Framework Convention on Climate Change requires that countries develop, update, publish and maintain national inventories using internationally approved and comparable emissions and removals estimation methods for 7 GHGs (carbon dioxide, methane, nitrous oxide, sulphur hexafluoride, perfluorocarbons, hydrofluorocarbons and nitrogen trifluoride). Canada's inventory is developed in accordance with the recently revised United Nations Framework Convention on Climate Change Inventory Reporting Guidelines for Annex I Parties  (PDF; 1.67 MB) which require the use of the 2006 methodological guidance developed by the Intergovernmental Panel on Climate Change. The Intergovernmental Panel on Climate Change guidelines are based on the best available science and developed through an international process that involves testing of methods through ongoing inventory development, country studies, technical and regional workshops, and national and international experts consultations.

Emissions calculation

In general, GHG emissions are estimated by multiplying activity data by the associated emission factor.

Activity data refer to the quantitative amount of human activity resulting in emissions during a given time period. The annual activity data for fuel combustion sources, for example, are the total amounts of fuel burned over a year.

Emission factors are based on samples of measurement data, and are representative rates of emissions for a given activity level under a given set of operating conditions. It is the estimated average emission rate of a given pollutant for a given source, relative to units of activity.

Guidelines produced by the Intergovernmental Panel on Climate Change for countries reporting to the United Nations Framework Convention on Climate Change provide various methods for calculating GHG emissions from a given human activity. The methods for estimating emissions are divided into "tiers," each encompassing different levels of activity and technological detail. The same general structure is used for all tiers, while the level of detail at which the calculations are carried out can vary. Annex 3 of the National Inventory Report describes the methods used to estimate Canada's GHG emissions and illustrates that the selection of Intergovernmental Panel on Climate Change method type is highly dependent on the importance of each category and the availability of data.

Carbon dioxide equivalents

Greenhouse gas emissions are reported in carbon dioxide equivalents (CO₂ eq), determined by multiplying the amount of emissions of a particular greenhouse gas by the global warming potential of that gas. Greenhouse gases differ in their ability to absorb heat in the atmosphere due to their differing chemical properties and atmospheric lifetimes. For example, over a period of 100 years, methane's potential to trap heat in the atmosphere is 25 times greater than carbon dioxide's potential. Therefore, methane is considered to have a global warming potential of 25. The Intergovernmental Panel on Climate Change publishes the global warming potentials and atmospheric lifetimes for each GHG; these can be found in Table 1-1 of the National Inventory Report.

Greenhouse gas emissions by economic sector

The Greenhouse gas emissions by economic sector indicator represents a different classification than the activity sector emissions prescribed by the Intergovernmental Panel on Climate Change's methodological guidance and United Nations Framework Convention on Climate Change's reporting guidelines. Instead of reporting on Canada's emissions by activity, GHG emissions have been allocated to the economic sector in which they are generated (for example, transport emissions directly supporting an industrial activity, like off-road trucks in mining activities, have been allocated to the economic sector in which they are generated rather than to the transportation "activity" sector). A comprehensive detailing of the emissions reported by economic sector can be found in chapter 2 and Annex 10 of the National Inventory Report.

Greenhouse gas emissions from the transport sector

The Greenhouse gas emissions from the transport sector indicator was calculated using a classification adapted from the one presented in Annex 10 of the National Inventory Report.

For the passenger transport, National Inventory Report's "Cars, light trucks and motorcycles" category was split into 2 separate categories ("Cars" and "Light trucks"), and the "Motorcycles" data were combined with the existing "Bus, rail and aviation" category.

For the freight transport, National Inventory Report's "Heavy duty trucks and rail" category was split into 2 separate categories. "Rail" data were then combined with the existing "Aviation and marine" category.

No change was made to the "Other: recreational, commercial and residential" category.

Quality assurance, quality control and uncertainty

Quality assurance and quality control procedures are an essential requirement of the GHG inventory development and submission process. Quality assurance and quality control procedures ensure and improve transparency, consistency, comparability, completeness and confidence in the national emissions for the purpose of meeting Canada's reporting commitments under the United Nations Framework Convention on Climate Change. Chapter 1 (section 1.3) of the National Inventory Report provides a complete description of the quality assurance and quality control procedures.

Uncertainty analysis helps to prioritize improvements and to guide decisions on methodological choices. Annex 2 of the National Inventory Report presents the uncertainty assessment for Canada's GHG emissions. Further details on uncertainty related to specific sectors can be found in the uncertainty sections of chapters 3 through 7 of the National Inventory Report.