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Data Sources and Methods for the Greenhouse Gas Emissions Indicators

5. Caveats and limitations

Annex 2 of the National Inventory Report (NIR) presents the uncertainty assessment for Canada's greenhouse gas (GHG) emissions. Further details on uncertainty related to specific sectors can be found in the uncertainty sections of chapters 3 through 7 of the NIR.

The sum of emissions from all provinces and territories does not equate to the national total, because emissions from some minor sources are estimated only at the national level. In particular, GHG emission estimates from consumption of perfluorocarbons (PFCs) and nitrogen trifluoride (NF3), as well as emissions of sulphur hexafluoride (SF6) from semi-conductor manufacturing, are only available at the national level. Nevertheless, the trends in emissions from provinces and territories are considered representative of the actual emission trends in these jurisdictions.

As part of the continuous improvement process, recalculations are performed annually on Canada's previously reported GHG emission estimates, to reflect updates to source data and estimation methodology. Chapter 8 (section 8.1) of the NIR provides a summary of the recalculations that occurred due to methodological changes and/or refinements since the previous submission, with a brief description, justification and summary of individual impacts on previously reported emission estimates.