The greenhouse gas account covers annual emissions of the residuals carbon dioxide, methane, and nitrous oxide by industry, governments, institutions, and households. The unit of measure is kilotonnes.
The main data sources for the emissions estimates are the Energy Account and the National Inventory Report on Greenhouse Gas Sources and Sinks (NIR) published by Environment Canada.
The NIR is Canada’s official government response to Canada’s obligations under the United Nations Framework Convention on Climate Change (UNFCCC). It provides estimates of emissions for seven greenhouse gases from energy use, industrial processes and other sources. The reporting requirements of the UNFCCC differ from the methodological guidelines of the SEEA, and as such there are differences between the totals reported in the Greenhouse Gas Account and the NIR. A reconciliation table is included with the Greenhouse Gas Account to explain these differences, which are also outlined in more detail below.
Greenhouse gas emissions estimates are calculated based on the Energy Use Account and emissions factors provided in the NIR. Emissions from industrial processes and other sources are taken directly from the NIR and attributed to the appropriate industries using the detailed data tables that Environment Canada submits to the UNFCCC.
The differences between the greenhouse gas emissions according to Environment Canada’s NIR and Statistics Canada’s Physical Flow Accounts (PFA) are due to two main reasons: a) conceptual differences between the UNFCCC reporting guidelines and the SEEA, and b) different data sources or lack of data preventing an accurate allocation of some types of emissions.
The largest conceptual difference between the NIR and the PFA is in the treatment of emissions stemming from the combustion of biomass (specifically wood and spent pulping liquor). UNFCCC guidelines exclude CO2 emissions from biomass combustion because this CO2 can also be absorbed through biomass production. SEEA guidelines focus on the estimation of emissions from economic units without accounting for the potential re-absorption of those emissions later.
Emissions from solid waste are the second largest conceptual difference. Emissions from landfill gas could be allocated to the waste management industry, but these emissions are not a result of current production: they represent releases associated with the decay of waste discarded in previous accounting periods. As such, they are not included in the Greenhouse Gas Account since they would not vary with current period economic output and thus would not yield proper conclusions if used in conjunction with the Input-Output tables for modeling purposes.
International aviation fuel purchases are the third largest conceptual difference. The UNFCCC requires airline emissions to be calculated based on the national territory. The SEEA requires that those emissions are based on the residence principle, meaning that the Greenhouse Gas Account must include purchases and thus emissions of aviation fuel abroad by domestic airlines and exclude those purchases and related emissions of foreign airlines in Canada. The NIR total for emissions covers those that occur over Canadian territory regardless of the ownership of the airline, and excludes emissions of domestic aircraft abroad (although these are included elsewhere in the NIR for information purposes).
Four gases are covered in Environment Canada’s NIR that are not covered in the Greenhouse Gas Account, namely HFCs, PFCs, SF6 and NF3. These are excluded from the PFA since there are no data available to allocate these emissions across industries and households. Several of these substances are refrigerants used in many industries, and attributing the leaks of the gases properly cannot be done with current data sources. The small amount of SF6 emissions is a result of processes in several distinct industries, and the data to do this allocation properly are also not available. Emissions from solvent use suffer from the same data gap.
Another conceptual difference is the inclusion in the PFA of prescribed burns in the forestry industry as an industrial process that is part of the production function for forestry. This is allocated to the Land Use, Land-Use Change and Forestry section of the NIR.
The final difference between the NIR and the greenhouse gas account relates to the consumption of motor gasoline. Environment Canada treats all transportation activity as a separate sector in the NIR. The fuel use from this activity is modeled so that it can be attributed to different vehicle types for the calculation of emissions. The modeling process allows for a discrepancy between the modeled fuel use and the fuel use totals from Statistics Canada’s energy supply and demand balances. The Greenhouse Gas Account retains the fuel consumption amount from the energy balances, leading to the difference between the two accounting approaches.
The remaining statistical difference results from other sources including changes to source data that are required to reconcile that information with other data sources.