Questions on personal carbon footprints

A very attentive reader asked some excellent questions about my very last ECO work product, the factsheet on individual carbon footprints. We are so glad to see it being used. Here are the questions and the answers:

"I’ve recently been poring over your “Reducing My Footprint” report (it’s SO helpful!) and have a couple questions regarding the breakdown of overall Ontario emissions: 

  • Question 1: In the Appendix, you mention that about 1/3 of Ontario’s GHG emissions (within-geographic-boundary, I presume) are from fossil fuel combustion in people’s personal vehicles and home furnaces. You then mention the issue of multi-unit dwellings and how the report decided to treat all residential heating as a direct source of emissions. Does this mean that all residential heating-related emissions were included in this 1/3, regardless of the energy source (ie including electric heat and wood as well as fossil fuels)? Or just that all fossil-fuel based residential heating was included, regardless of dwelling type?

Answer to Question 1:

The "residential heating" stat is the per capita emissions from all residential building fossil fuel use. Electric heating would be captured in the tiny electricity wedge. Emissions from wood is not included. So it is calculated as an average across building types, as opposed to a median representing one particular building or fuel type. That said, we translated the average into equivalent natural gas emissions as an example.

  • Question 2: Also in the Appendix, you mention that in 2009, Ontario’s consumption-based emissions were estimated to divide out to 19 tonnes per person, although this includes emissions that are not controlled by individual-level lifestyle choices. I calculated that, with a 2009 population of 13 million, this would equate to 247 million tonnes of consumption-based emissions, only 143 million of which would be attributable to individual lifestyle choices if we assume that Ontarians in 2009 had a similar lifestyle-based carbon footprint as you calculated them to have in 2016: 11t. That means that 104 million tonnes are left to be attributed to consumption-based emissions that are NOT controlled by individual-level lifestyle choices. I know you mention one example of such an emission source to be government spending, but that seems to me to be a LOT of emissions (42% of our total consumption-based emissions) to be associated with government-spending! Unless I don’t have a full conception of what all the government spends money on. What else would be in this category? I am trying to figure this out.

Answer to Question 2:

The main take-away – due to the nature of the data available, it was not possible to put together a comprehensive list of each type of greenhouse gas (GHG) emission source excluded from the average carbon footprint of an Ontarian, relative to Ontario's per capita consumption-based emissions. However, the emissions associated with government spending would unquestionably be an important part of such a list. Approximately 40% of Canada’s GDP is government spending.

Footnote 78 of the backgrounder (and the “average emissions” textbox on p. 21 of the backgrounder) specifies in detail how the “other goods and services” wedge was calculated. This wedge includes the embodied GHG emissions of goods and services not covered in the other wedges. It was calculated using Statistics Canada household spending data for Ontario along with GHG emission factors from an Environmentally-Extended Input-Output Life Cycle Inventory model (see footnote 77 for a description of these types of models). The types of emission categories included in the “other goods and services” wedge, each with a different GHG emission factor, were based on the CoolCimate Network GHG calculator that was put together by researchers at the University of California, Berkeley (these emission categories were then matched with the Statistics Canada household spending categories). It is not clear to what extent the emissions associated with these categories (listed in footnote 78) are representative of those from all the goods and services that individuals consume. It is possible that other categories should also be included – however, the GHG emission factors for any such categories were not available.

As the data used for the carbon footprint estimates in the report were compiled from many sources that used different measurement techniques and modelling, substantial uncertainty should be expected (see “How certain are these numbers?” textbox on p. 29). This is especially the case for the “other goods and services” wedge.

Moreover,  specific emissions gap you calculated might be an overestimate because it compares 2009 consumption-based emissions (i.e., the 19 tonne per capita estimate based on a 2016 paper by Dolter and Victor) with the 2016 emissions calculated for this report. Ontario phased out coal-fired electricity between 2005 and April 2014.

Hope this helps. Do let us know how you are using our report.

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