Land-based greenhouse gas emissions and removals

National land-based greenhouse gas emissions and removals

Key results

• Between 1990 and 2018, land-based GHG emissions and removals ranged from removals of about 100 megatonnes of carbon dioxide equivalent (Mt CO₂ eq)^{Footnote 2} in 1992 to emissions of about 240 Mt CO₂ eq in 2018
  
• In 2018,
  • natural disturbances (such as wildfires and severe insect infestations) accounted for emissions of about 250 Mt CO₂ eq
  • human activities accounted for removals of 13 Mt CO₂ eq

National land-based greenhouse gas emissions and removals, 1990 to 2018

How this indicator was calculated

Note: Natural disturbances refer to emissions and removals related to wildfires and large forest insect infestations. Human activities refer to emissions and removals from managed lands and includes settlements, the forestry sector, agricultural land and wetlands. Net exchange is calculated by subtracting removals from emissions.
Source: Environment and Climate Change Canada (2020) National Inventory Report 1990-2018: Greenhouse Gas Sources and Sinks in Canada.

Natural disturbances such as forest fires and large insect infestations have occurred in Canada's forests for thousands of years. These disturbances are part of the natural life cycle of the forest and generally help the forest renew itself. However, there is evidence that climate change is driving an increase in natural disturbances. These disturbances can contribute to the release of large amounts of GHGs into the atmosphere through burning and decay of dead trees, as well as significant removals as forest regenerates over time.^{Footnote 3} For the past 20 years, the total net GHG exchange (that is, the land-based GHG emissions minus removals) has been significantly impacted by these natural disturbances.

In managed forests, emissions and removals due to natural disturbances such as forest fires or insect infestations are associated with human activities under specific circumstances. These circumstances are described in the methods section.

Land-based GHG emissions and removals from human activities

Land-based GHG emissions and removals from human activities are commonly referred to as land use, land-use change and forestry (LULUCF) according to international standards.

Key results

• In 2018, lands dominated by human activities removed 13 megatonnes of carbon dioxide equivalent (Mt CO₂ eq) from the atmosphere
  • forestry and agricultural land contributed removals of 11 and 6.2 Mt CO₂ eq, respectively
  • wetlands and settlements contributed emissions of 2.6 and 1.8 Mt CO₂ eq, respectively
• The forestry sector had the largest influence on the totals for all years in the time series and displayed the greatest variations between years

Land-based greenhouse gas emissions and removals from human activities by activity sector, Canada, 1990 to 2018

How this indicator was calculated

Note: Net exchange is calculated by subtracting removals from emissions.
Source: Environment and Climate Change Canada (2020) National Inventory Report 1990-2018: Greenhouse Gas Sources and Sinks in Canada.

Regional land-based emissions and removals from human activities

Key results

From 1990 to 2018,

• the agriculturally important Prairie region increased removals from 0.65 megatonnes of carbon dioxide equivalent (Mt CO₂ eq) to 12 Mt CO₂ eq
• the Southeastern region went from emissions of 3.0 Mt CO₂ eq to removals of about 4.1 Mt CO₂ eq
• the Mountain region, which is important for forestry, went from removals of 51 Mt CO₂ eq to emissions of about 7.3 Mt CO₂ eq

Regional land-based greenhouse gas emissions and removals from human activities, Canada, 1990 to 2018

How this indicator was calculated

Note: Regions are based on the location of the human activities across the country. Net exchange is calculated by subtracting removals from emissions.
Source: Environment and Climate Change Canada (2020) National Inventory Report 1990-2018: Greenhouse Gas Sources and Sinks in Canada.

The increased removals of GHGs in the Prairies can be attributed to changes in agricultural land management practices, such as the adoption of conservation tillage and the reduced use of summerfallow. These changes in land management resulted in decreased soil disturbance and thereby lower releases of carbon from soil organic matter.

In the West Coast and Southeastern regions, forestry management practices (changes in harvest rates and forest regeneration) contributed to the reduction in emissions.

The decrease in GHG removals in the Mountain and Boreal regions is related to increased forest harvesting (in part in an effort to salvage timber after Mountain Pine beetle kill) and to a reduction in carbon removals from forests. The latter is due to insect infestations and fire in managed forests, which reduced the area of mature growing trees in these forests, increased decomposition and increased harvesting of dead or dying standing trees (salvage logging).

Land-based emissions and removals from natural disturbances

Forests remove carbon from the atmosphere as they grow and release it along with other GHGs when they decay after dying or burn in forest fires.

Key results

• Wildfires had the largest influence on land-based emissions and removals from natural disturbances (emissions of 260 megatonnes of carbon dioxide equivalent [Mt CO₂ eq] in 2018)
• Emissions caused by insect infestations reached a peak of 44 Mt CO₂ eq in 2008 and in 2018 were 22 Mt CO₂ eq
• Removals due to forest regrowth post wildfire reached a peak of 64 Mt CO₂ eq in 1994 and in 2018 were 27 Mt CO₂ eq

Land-based greenhouse gas emissions and removals from natural disturbances in managed areas, Canada, 1990 to 2018

How this indicator was calculated

Note: Wildfire emissions and removals are divided in 2 categories, (1) wildfires - immediate and (2) post wildfires. Wildfires - immediate include emissions from trees and soils from the burning of wildfires. Post wildfires include emissions released by the decay of dead trees and soil organic matter and removals related to forest regeneration. Insect disturbances include emissions from the decay of organic matter and removals from natural regeneration. Net exchange is calculated by subtracting removals from emissions.
Source: Environment and Climate Change Canada (2020) National Inventory Report 1990-2018: Greenhouse Gas Sources and Sinks in Canada.

Natural disturbances are an important factor in determining whether forests remove or release GHGs each year. These disturbances result in immediate emissions such as from the burning of trees, as well as post-disturbance emissions and removals. Post-disturbance emissions are from the gradual decay of dead organic matter. Post-disturbance removals are related to the natural regeneration and regrowth of forests.

The variability in emissions and releases from natural disturbances can be very large from year to year. For example, emissions from managed lands were lower in 2016 than in adjacent years because of the smaller area burned.^{Footnote 4} However, since the mid-2000s, emissions from wildfires and insect disturbances have generally been higher than in previous years.

About the indicator

What the indicator measures

The Land-based greenhouse gas emissions and removals indicator tracks exchanges of greenhouse gas (GHG) emissions and removals between the atmosphere and Canada's managed lands. Reported GHG emissions and removals from human-related activities result from land use and land-use change activities from the forestry sector (managed forested land and harvested wood products), agricultural land (cropland and grassland), wetlands (peat extraction and reservoirs for hydropower) and settlements. The indicator also tracks GHG emissions and removals from natural disturbances (insect infestations and wildfires) on Canada's managed lands.

Why this indicator is important

GHG emissions and their increasing concentrations in the atmosphere are having significant impacts on the environment, human health and the economy. Tracking the trends in Canada’s land-based GHG emissions and removals provides a useful context for understanding how different management activities could reduce emissions and increase removals over time. This indicator could also help identify opportunities for mitigating the impacts of climate change and the potential for enhancing carbon sequestration.

The distinction between emissions and removals from human activities versus natural disturbances allows for a better understanding of emissions that could be directly managed in the near to medium term. The National Inventory Report has made this distinction since 2017.

Related indicators

The Greenhouse gas emissions indicators report trends in total anthropogenic (human-made) GHG emissions at the national level, per person and per unit gross domestic product, by province and territory and by economic sector.

The Global greenhouse gas emissions indicator provides a global perspective on Canada's share of global GHG emissions.

The Carbon dioxide emissions from a consumption perspective indicator shows the impact of Canada's consumption of goods and services, regardless of where they are produced, on the levels of carbon dioxide released into the atmosphere.

The Progress towards Canada's greenhouse gas emissions reduction target indicator provides an overview of Canada's projected GHG emissions up to 2030.

The Greenhouse gas emissions from large facilities indicator reports GHG emissions from the largest GHG emitters in Canada (industrial and other types of facilities).

Data sources and methods

Data sources

Emissions and removals data from Canada's National Inventory Report are used to produce the Land-based greenhouse gas emissions and removals indicator for natural disturbances and land use, land-use change and forestry (LULUCF) activity on managed lands. Managed lands are defined by the Intergovernmental Panel on Climate Change (IPCC) as "land where human interventions and practices have been applied to perform production, ecological or social functions."^{Footnote 5} Information on the land category definition and representation of managed lands is available in Chapter 6 of the National Inventory Report.

Land-based greenhouse gas (GHG) emissions and removals include emissions and removals of carbon dioxide (CO₂). It also includes emissions of methane (CH₄), nitrous oxide (N₂O), and indirect CO₂ from the atmospheric oxidation of carbon monoxide (CO) due to controlled biomass burning; CH₄ and N₂O emissions from wetland drainage and rewetting due to peat extraction; and N₂O released following land conversion to cropland.

Methods

Land-based GHG emissions and removals are quantified using methods that are consistent with an internationally agreed methodological framework set out in the 2006 IPCC Guidelines for National Greenhouse Gas Inventories. The methodologies used to estimate emissions and removals are reviewed, updated and improved on a periodic basis. Collaborative work with sector experts from within and outside Environment and Climate Change Canada is undertaken to incorporate available expertise and the latest advancements in scientific knowledge. Further information on these methods is available through Environment and Climate Change Canada's National Inventory Report.

Caveats and limitations

The methodologies for compiling land-based GHG emissions and removals improve over time. As a result, the land-based emissions and removals data reported in the indicator may be different from previously published estimates.

Canada is a vast country with heterogeneous landscapes and climates. Factors such as geographic location, climatic conditions, plant species and age, and management activities all play a role in affecting the net amount of GHG that is removed or released back to the atmosphere from each location in Canada. The land-based emissions and removals data provide a simplified representation of the complex reality and may not account for all relevant ecological processes.

Current reporting of land-based emissions and removals does not account for climate feedback other than that expressed through changes in disturbance regimes. Climate feedback mechanisms can either amplify (positive feedback) or diminish (negative feedback) the effects of a changing climate. For example, as rising concentrations of GHGs warm Earth's climate, permafrost begins to melt. This melting releases the organic carbon stored, contributing to GHG releases that cause more warming, which causes more melting, and so on, in a self reinforcing cycle.

For a complete discussion of the caveats and limitations with respect to land-based GHG emissions and removals data, refer to the methodological issues sections in Chapter 6 of Canada's 2020 National Inventory Report.

Resources

References

Environment and Climate Change Canada (2020) National Inventory Report 1990-2018: Greenhouse gas sources and sinks in Canada. Retrieved on May 6, 2020.

Intergovernmental Panel on Climate Change (2003) Good Practice Guidance for Land Use, Land-use Change and Forestry. Retrieved on May 6, 2020.

Intergovernmental Panel on Climate Change (2006) 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Vol. 4: Agriculture, Forestry and Other Land Use. Retrieved on May 6, 2020.

Kurz WA, Hayne S, Fellows M, MacDonald JD, Metsaranta JM, Hafer M and Blain D (2018) Quantifying the impacts of human activities on reported greenhouse gas emissions and removals in Canada’s managed forest: conceptual framework and implementation. Canadian Journal of Forest Research 48: 1-14. Retrieved on August 5, 2020.

Warren FJ and Lemmen DS, editors (2014) Canada in a Changing Climate: Sector Perspectives on Impacts and Adaptation. Government of Canada. Retrieved May 6, 2020.

Related information

• Canada's Action on Climate Change
• Climate Change
• Greenhouse gas emissions
• Greenhouse gas emissions: drivers and impacts