EIA and a carbon footprint threshold

Since carbon dioxide is the major source of anthropogenic greenhouse gases (GHG) (see figure 1), it is relevant to evaluate the environmental impact of our activities by evaluating the equivalent amount of carbon dioxide we are generating, i.e. our carbon footprint [1].

Figure 1. USA anthropogenic greenhouse gases proportions in 2009 (based on Tg CO2e) [2]

How can the carbon footprint concept be integrated into the Environmental Impact Assessment (EIA) process?

One of the first and maybe most important phase of the EIA process is the screening phase [3].   Among the different screening approaches, one is the threshold-based approach where the EIA process automatically applies to the project being investigated if it is evaluated that an activity-specific quantitative threshold is reached.

These activity-specific thresholds might need to be individually re-evaluated in the future if their initial perceived effect on the environment is later seen to have a different impact based on climate change and new environmental conditions.

Integrating a “carbon footprint threshold” in the EIA screening process could be feasible especially since GHG assessment frameworks are already taking shape worldwide:

  • ISO 14064 standards: Identifying, quantifying and monitoring of GHG emissions.  The quantifying aspect of this framework could serve as the basis for a “carbon footprint threshold” and the monitoring aspect could be used in the EIA process.
  • Government of Canada “Regulatory Framework for Industrial Greenhouse Gas Emissions”: Defining minimum emission thresholds to exclude smaller facilities which are less contributing to the overall GHG emissions of their specific sector.  Facilities from chemicals, nitrogen-based fertilizers and natural gas pipelines sectors could be excluded from the regulation if their annual level of emissions is below 50,000 tonnes of CO2e.
  • USA Environmental Protection Agency (EPA) “Mandatory Reporting of Greenhouse Gases Rule”: Most facilities emitting more than 25,000 tonnes of CO2e annually need to submit an annual report to the EPA.

Of course, no system is perfect.  Converting the actual activity-specific thresholds to a unified “carbon footprint threshold” might raise questions such as:

  • How would a carbon footprint be evaluated in the case of decommissioning a facility?  Would this activity decrease the actual carbon footprint?  In that case, could a carbon credit be an incentive for companies to ensure that their end-of-life facilities are adequately decommissioned?
  • What about other types of pollutant not associated with GHG? Can all types of pollutant be eventually converted as CO2e in a “carbon footprint threshold”?
  • And more importantly: If a carbon tax system is implemented, how well could such a “carbon footprint threshold” system works if the threshold limit can be manipulated with the purchase of carbon credits?

Carbon footprint is not the ultimate assessment parameter and surely not the only one but by reducing the multitude of project-specific thresholds (who will need to be re-evaluated over time), the EIA process would be streamlined and made more transparent.  Since a “carbon footprint threshold” would be directly associated with climate change, a project proponent who tries to lower its carbon footprint in order to avoid triggering the EIA process, would actually have achieved the main objective of reducing its environmental impact!


GOVERNMENT OF CANADA (2008) – Turning the Corner: Regulatory Framework for Industrial Greenhouse Gases Emissions.  ISBN 978-0-662-05525-9.

INTERNATIONAL ORGANIZATION FOR STANDARDIZATION (2006) – ISO 14064-1:2006, Greenhouse gases – Part 1: Specification with guidance at the organization level for quantification and reporting of greenhouse gas emissions and removals.

NOBLE B.F. (2010) – Introduction to Environmental Impact Assessment, A Guide to Principles and Practice (OXFORD University Press, 2nd Edition).

WRIGHT L., KEMP S., WILLIAMS I. (2011) – “‘Carbon footprinting’: towards a universally accepted definition”. Carbon Management 2 (1): 61-72.

USA ENVIRONMENTAL PROTECTION AGENCY (2009) – EPA–HQ–OAR–2008–0508, Mandatory Reporting of Greenhouse Gases Rule.  Federal Register, Vol. 74, No. 209.

USA ENVIRONMENTAL PROTECTION AGENCY (2011) – EPA 430-R-11-005, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2009.

[1]  WRIGHT et al. (2011) define carbon footprint as: “A measure of the total amount of carbon dioxide (CO2) and methane (CH4) emissions of a defined population, system or activity, considering all relevant sources, sinks and storage within the spatial and temporal boundary of the population, system or activity of interest. Calculated as carbon dioxide equivalent (CO2e) using the relevant 100-year global warming potential (GWP100).”

[2]  EPA (2011) – EPA 430-R-11-005, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2009.

[3]  NOBLE (2010) defines screening as the “narrowing of the application of EIA to projects that require assessment because of perceived significant environmental effects or specific regulations”.


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