For most organisations, scope 3 is the largest category of emissions[i] and yet academic and industry literature yields little in the way of specific guidance for the practitioner wishing to accurately measure their full emissions profile. The GHG Protocol[ii], widely recognised as the leading information source, is far from prescriptive and our leading national publication on emission factors, the National Greenhouse Accounts Factors[iii], includes information on scant few scope 3 sources.  EPA Victoria’s leadership is certainly helpful to many members of this network, but is still limited to the scope offered through the example of their own operations.

In light of the limited guidance available, a research project conducted at Monash University tested whether a de facto standard for addressing scope 3 emissions exists in Australia.  Information from twenty two organisations, most of which had assessed their own greenhouse gas emissions, was used as a sample to evaluate current emissions assessment practices. The research specifically focused on completeness and accuracy, two of the five principles outlines by the GHG Protocol for a quality greenhouse assessment.  This article will focus on the findings relating to completeness, which was evaluated through the number of scope 3 emission sources included and excluded.

Including scope 3 in the organisations emissions assessment was mandatory for participation in the study and participants were found to include anything from two to thirteen scope 3 sources. The majority of organisations reported seven sources of scope 3 emissions or less, but a clear leadership group reported eleven sources or more. Thus no common standard of completeness was in evidence but best current practice for a complete emissions inventory entailed including thirteen scope 3 emission sources and, further still, including a round up value to cover for sources not individually measured.

An analysis of possible drivers for this differential was conducted, with longevity of reporting, previous experience, qualifications, drive from senior leadership and carbon neutrality intentions all showing no correlation to reporting higher numbers of emission sources.  The use of particular information sources, such as EPA Victoria or the National Greenhouse Accounts Factors, were also found to have no significant bearing on which organisations reported higher numbers of emission sources. The one element that did appear to impact the completeness of an assessment was access to a greater level of expertise, either internally or externally to the organisation through the use of consultants.

Nearly all respondents recognised a number of emission sources not included in their inventory, which they had either determined not to include or desired to include in their inventory in future.  Inclusions and desired future inclusions were often based on opportunity and ease rather than any established level of importance in each organisation’s emissions profile.  Also, while many excluded emissions were justified on a basis of materiality, no participants had established a formal materiality threshold and so these determinations were made subjectively.

With no single source of guidance or emission factor information available, there is no “quick fix” to developing a more comprehensive assessment. The recommendations arising from this research to best meet the principle of completeness are:

  1. Include as many sources as possible within your time/budget/knowledge constraints
  2. Define and disclose a materiality threshold if one is to be applied
  3. Disclose any emission sources you have chosen not to, or not been able to calculate
  4. Unless your report is in line with best practice for completeness as outlined above, chances are your report is at least a few percent short of your true emissions.  Consider making an allowance in the report to cover the shortfall.

[i] Huang, Y. A., Lenzen, M., Weber, C. L., Murray, J. & Matthews, H. S. 2009, The role of Input-Output analysis for the screening of corporate carbon footprints. Economic Systems Research, 21, 217-242.

[ii] WBCSD & WRI 2004, The Greenhouse Gas Protocol: A Corporate Accounting and Reporting Standard  Revised Edition, World Business Council for Sustainable Development and World Resources Institute, Geneva, Switzerland,

[iii] DCCEE, 2010, National Greenhouse Accounts (NGA) Factors July 2010, Department of Climate Change and Energy Efficiency, Canberra.

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