Carbon definitions and typologies in environmental impact assessment: greenhouse gas confusion?

Abstract

Estimation of emissions of greenhouse gases (GHG) is becoming an established part of assessing sustainability within environmental impact assessment (EIA). However, a comparative study of 25 environmental impact statements (EISs) to analyse the practice of accounting for emissions during the EIA process suggests that consideration of the effects of development on emissions of GHG is poorly understood. The extent to which assessment is actually carried out is also inconsistent and sporadically implemented. A key indicator appears to be the varying and sometimes contradictory use of technical terminology, particularly of the term ‘carbon’ and its similar phraseology. This paper provides a critical evaluation of the differing terminology that is applied to GHG assessments undertaken as part of EIA process and explores the effect that misuse of these terms could have on an impact EIS.

Keywords:

• greenhouse gas
• carbon
• climate change
• typology
• EIA

Introduction

The calculation, or estimation, of greenhouse gas (GHG) emissions is rapidly becoming a key metric for assessing the overall sustainability of an organization, action, project or product. The use of ‘carbon calculators’ and toolkits is now so widespread across industries and processes that the expression ‘carbon footprint’ has almost become synonymous with ‘environmental impact’, although it has been suggested that the process of calculating emissions can be flawed (Jeswiet & Nava 2009; Johnson 2009).

As part of this developing trend, the need to consider GHG emissions is becoming more common in the environmental impact assessment (EIA) process. The UK Institute of Environmental Management and Assessment (IEMA) state in their Climate Change Mitigation and EIA guidance document (IEMA 2010) that 88% of respondents to a survey on current practice consider that ‘where relevant, carbon emissions should be considered in the assessment and reported in the Environmental Statement’ (p. 1). However, a comparative study undertaken by the authors to analyse current practice of accounting for emissions during EIA suggests that consideration of the effects of development on GHG emissions is poorly understood, whilst assessment itself is inconsistently and sporadically implemented. A key indicator of this oversight appears to be the inconsistent and potentially contradictory use of technical terminology, particularly the term ‘carbon’ and its similar phraseology.

This paper provides a critical evaluation of the differing terminology that is employed in 25 environmental impact statements (EISs) from a range of developed and ‘transitional’ countries, produced for a range of development projects. We explore the effect that misuse of these terms could have on the quality and robustness of the assessment process. The aim is to provide a ‘starting point’ for a consistent approach to assessment of GHG emissions for EIA practitioners and guidance on appropriate use of terminology.

The paper is laid out as follows: section 2 provides background information on some of the key terminology used to describe GHG emissions; section 3 describes the methodology, section 4 discusses the findings from the study, whilst section 5 makes recommendations on good practice.

Background on key terminology – potential for confusion

Understanding the role of emissions in climate change is a complex science (see for example, Gillenwater 2008). In the following section we outline some of the key terminology used to refer to GHG in EIA.

Terms such as ‘low carbon’ and ‘zero carbon’ are often used to refer to specific issues related to climate change (e.g. Bailey & Wilson 2009), but also as general terms relating to broader issues around environmental sustainability. In addition, although used to refer to carbon quantification, environmentally detrimental activities or climate impacts, the single term ‘carbon’ is most often used as a shorthand term for ‘carbon dioxide’ (CO₂) or ‘carbon dioxide-equivalent’ (CO₂-e). In certain cases, it is also used as reference to the mass of carbon contained within a released volume of CO₂.

According to the Intergovernmental Panel on Climate Change (IPCC), carbon dioxide (CO₂) is ‘a naturally occurring gas and also a by-product of burning fossil fuels and biomass, as well as land-use changes and other industrial processes. It is the principal anthropogenic GHG that affects the Earth's radiative balance’ (IPCC 2007). In some cases, for example where emission of other gases is negligible, or calculations of total GHG emissions are not possible, quantifying emissions of ‘carbon dioxide’ is appropriate. However, often references to ‘carbon dioxide’ or ‘CO₂’ emissions actually quantify total emissions, in terms of ‘carbon dioxide-equivalent’. For example, guidance to the UK Carbon Reduction Commitment (CRC), provided to organizations that are required to measure emissions (DECC 2010), suggests that the measure is only of carbon dioxide. However, closer examination shows that the methodology provided (developed by the UK Carbon Trust) actually calculates carbon dioxide-equivalent emissions (Carbon Trust 2010).

Carbon dioxide is only one of a number of chemical species considered to contribute to climate change. Collectively these are called the greenhouse gases. The IPCC index for these gases (termed the Global Warming Potential, GWP) allows for a relative estimate to be made of the possible impact of each of the gases on climate change by assigning each a GWP value relative to carbon dioxide, expressed as carbon dioxide-equivalent (CO₂-e). The carbon dioxide-equivalent for a gas is derived by multiplying the tonnes of the gas by the associated GWP. The European Environment Agency Environmental Terminology and Discovery Service provides a useful example of this: ‘the GWP for methane is 21 and for nitrous oxide 310. This means that emission of 1 million metric tonnes of methane and nitrous oxide respectively is equivalent to emissions of 21 and 310 million metric tonnes of carbon dioxide’ (European Environment Agency, undated).

With so many terms, each with different connotations, it could be considered that the consequence of inventing the term ‘carbon dioxide-equivalent’ (or CO₂-e), although designed as a simple way of representing a complex issue, is that its similarity to other terms has actually resulted in an increase in confusion, a lack of clarity and the potential for misuse and misunderstanding of the terms.

Methodology of comparative study

This paper is based on the findings of a short comparative study carried out by the authors to consider how ‘carbon’ is accounted for in EIA. The study arose from a discussion with practitioners that this was an area of practice in need of development. The study comprised an analysis of 25 EISs drawn from five ‘developed’ nations (UK, USA, Canada, Australia and New Zealand), and a series of six transitional nations (Egypt, Hong Kong, India, Russia, Georgia and Mauritius) and considered a range of developments (renewable energy, land transport, water resources, airport expansions, industrial and leisure developments). The developments chosen were those considered most likely to have included some consideration of GHG emissions and the characteristics of the ‘carbon narrative’ within the EISs was examined.

Our methodology to assess the characteristics of the narrative comprised:

•	comparison of terminology used to assess GHGs in each of the 25 EISs, in both general descriptive sections, and in calculations or estimates of emissions;
•	identification of which EISs provided explanations or justifications of GHG terms used in descriptions and calculations;
•	highlighting of where estimates of emissions based on toolkits or external methodologies were not recorded using correct terminology from the methodology when reproduced in the EIS (e.g. where a toolkit provides a result in carbon dioxide-equivalent, but the EIS records emissions as carbon dioxide).

A list of eight terms was drawn up (using the key terminology referred to previously) and these are shown as List 1. The first stage determined whether any of the eight terms were used in the EIS in reference to the impacts of the proposed projects. During this stage any other terms used in reference to GHG emissions were also recorded as ‘Other’. Assessment was carried out using a simple text search applied to each EIS to identify the expressions used.

List 1 – terms for assessment

•	carbon;
•	C;
•	carbon dioxide;
•	CO2;
•	CO2e /equivalent/eq;
•	carbon dioxide-equivalent;
•	greenhouse gas(es);
•	GHGs;
•	(other).

This list included each expression separately, and considered abbreviations as individual terms. While some terms could be considered interchangeable (such as C/carbon, CO₂/carbon dioxide) non-specialist readers of EISs could not be expected to know this. The assessment was designed with this in mind to consider all possible areas of confusion.

Each EIS was examined to identify whether an explanation or justification of the terms used to describe GHGs was provided (for example whether terminology reflected that used in calculation methodology or requirements of local law). Finally, for each EIS that specified that a particular toolkit or methodology for the estimation/calculation of GHG emissions had been used, the terminology within the EIS was contrasted with the prescribed terminology for that toolkit/method to determine the level of consistency between the two.

Certain expressions were excluded from the assessment, for example where terms such as ‘low carbon’ or ‘carbon neutral’ were used as part of official names for local or national policies and planning strategies, where carbon was considered only as a pollutant (hydrocarbon spills), or where carbon was considered only as a health impact (carbon monoxide).

Findings and discussion arising from the comparative study

Initially 41 EIS were collected for the study. However not all the EISs gathered for the study made any reference to GHG emissions (despite careful selection of a range of development types that theoretically would be likely to consider emissions). Of the EISs without GHG reference, two assessed major transport infrastructure projects, three concerned leisure projects and one concerned airport expansion. That projects of these types could be undertaken without reference to GHG emissions is striking. Once these were removed from the sample set, 25 EISs remained and the findings are based on assessment of these. Complete results of the assessment are shown in Table 1, but the comparative study revealed a number of notable issues from the sample EISs.

Table 1 Summary of assessment of GHG terminology.

		UK	Australia	USA	Canada	New Zealand	Others
Renewable energy	Number of GHG reference terms used	6	3	2	3	2	3
	Choice of GHG terms explained/justified?	No	No	No	No	Yes	No
	Consistent use of terms from calculations/method to EIS?	No	No calculation	Yes	No calculation	Yes	No calculation
Transport	Number of GHG reference terms used	4	5	2	1	No GHG reference	No GHG reference
	Choice of GHG terms explained/justified?	Yes	Yes	Yes	No	No GHG reference	No GHG reference
	Consistent use of terms from calculations/method to EIS?	Yes	Yes	No calculation	No calculation	No GHG reference	No GHG reference
Water	Number of GHG reference terms used	2	1	3	2	No GHG reference	No GHG reference
	Choice of GHG terms explained/justified?	Yes	Yes	Yes	No	No GHG reference	No GHG reference
	Consistent use of terms from calculations/method to EIS?	Yes	Yes	Yes	Yes	No GHG reference	No GHG reference
Airport expansion	Number of GHG reference terms used	4	1	No GHG reference	1	No EIS available	3
	Choice of GHG terms explained/justified?	No	No	No GHG reference	No	No EIS available	No
	Consistent use of terms from calculations/method to EIS?	Yes	Yes	No GHG reference	No calculation	No EIS available	No calculation
Industrial	Number of GHG reference terms used	5	1	2	1	No GHG reference	No GHG reference
	Choice of GHG terms explained/justified?	Yes	No	No	Yes	No GHG reference	No GHG reference
	Consistent use of terms from calculations/method to EIS?	Yes	Yes	Yes	Yes	No GHG reference	No GHG reference
Leisure, tourism, social	Number of GHG reference terms used	3	No GHG reference	1	No GHG reference	No GHG reference	1
	Choice of GHG terms explained/justified?	No	No GHG reference	Yes	No GHG reference	No GHG reference	No
	Consistent use of terms from calculations/method to EIS?	Yes	No GHG reference	Yes	No GHG reference	No GHG reference	No calculation

Using multiple terms for GHG reference

•	Only three EISs used a single, consistent reference to GHG emissions.

The assessment revealed that the most frequent problem was the use of multiple terms to describe GHG emissions. While inconsistency from one chapter to the next is explainable (if not excusable) by the use of multiple consultants, the assessment showed that terminology frequently changed during the course of individual chapters. The unintended effect of this appears to be increased confusion and reduced clarity with regard to the actual impact being discussed. To casual readers, changing terms can have the effect of making it unclear if the impact being discussed is the same or if new ideas have been introduced. This problem is exacerbated through the use of abbreviated terms. Using the carbon dioxide and carbon dioxide-equivalent abbreviations only improves the accessibility of the text when a single term is used consistently, not when several are used interchangeably.

Effect of lack of explanation of terms and choices

•	The majority of EISs (15 from 25) provided no explanation of GHG terms employed and their implications.

The lack of justification for the use of GHG terms is also a frequent problem. Again there is no clear explanation as to why this problem exists. With no clarification of terms, the effect is to further increase confusion for the non-expert reader with the potential to create resentment towards the project (Glasson et al. 2012), while for those involved in the projects under assessment, making impartial decisions on the suitability and sustainability of proposed development is made difficult, particularly if several options are being compared.

Effect of using wrong metrics for calculations

•	One EIS used terminology inconsistently between the calculations of emissions and the recording of these emissions in the EIS.

It is important to remember that there is a difference between contextual terms used in describing the issue and those used in empirical calculations. The confusion caused by using multiple terms to describe emissions has the potential to cause non-specialists difficulty in understanding the issue and in assessing the true impacts of proposed developments. However, the inconsistent use of terms for calculations is potentially more worrying in terms of impact. This occurred only once in the study. The EIS in question (from the UK) showed a methodology that provided a process to calculate emissions as ‘carbon dioxide-equivalent’, but the calculations and tables in the EIS provided some figures as ‘carbon dioxide’ and others as ‘carbon dioxide-equivalent’. Six other EISs provided an estimation of GHG emissions, but gave no information on the method of calculation, making it impossible to assess whether the designation of terms was consistent between methodology and EIS. If this error is replicated there is the potential for mistakes and under-/overestimation of the total impact from GHG emissions from a development. While quantitative assessments of impact in EIA are inevitably difficult and are frequently inaccurate (see Dipper 1998), using terms inconsistently from one estimate to the next makes it impossible to even compare emissions within individual projects and from one project to another. If EIA is considered to be a measure of sustainability (Weaver et al. 2008), assessing the total effect of a project, and the cumulative effect of multiple projects, then using a consistent approach and appropriate method for assessment is essential, both within individual EIAs and across EIAs, on a national and international level.

Effect of an inconsistent approach from country to country

•	Terms referring to GHGs varied from one EIS to the next, both within EIS from the same country, and from country to country.

Although similar in principle, EIA guidance and practice is already variable according to local jurisdiction (Lee & George 2000; Wood 2003), so the effect of differing approaches to terminology for GHG assessment can be considered simply to add to existing inconsistency. However, the effect of using more than one term for calculations from one country's EIS to the next has significant potential as a negative impact owing to the cumulative impact of GHG emissions. Where one country uses a fully disclosed assessment of all GHG emissions, accounting for all potential emissions, and another only accounts for carbon dioxide, the overall impact of development on a global scale is much harder to assess and in most cases will be higher than is actually reported.

This initial study is too small to draw conclusions on the contrasting approaches to GHG quantification from developed countries compared with developing countries, but does suggest some potential areas of concern in the wider global context and echoes the perception that EIS from developing nations are often ‘unsatisfactory’ (Lee & George 2000). That none of the studies from the ‘Other’ group provide justification or explanation of terminology used suggests that GHG consideration is either poorly understood or has yet to become a common element of EIA in these places. If the EIA approach in transitional nations either ignores any consideration of GHG emissions or chooses to use calculations without any basis in robust methodologies, there is significant potential to ‘hide’ the true effect on increased emissions through development. Taken further, when this lack of explanation and transparency is considered on a wider scale, taking account of levels of construction in rapidly emerging economies such as China and India, there is the potential for even greater levels of GHG emissions to be neglected, with potentially wider reaching impacts than any of the ‘local’ impacts traditionally considered in EIS.

Conclusions

As the study demonstrates, terminology used to describe GHG emissions varies, even between EIS produced within the same country, creating confusion, lack of transparency, difficulties in comparison and cumulative consideration both nationally and internationally, and occasionally the provision of inaccurate estimates of emissions. Although mistakes are being made, steps towards including GHG assessment are positive; GHG assessment provides a starting point for estimating cumulative effects of development, while the number of EISs that include reference to GHG emissions demonstrates that practitioners are beginning to understand the importance of considering the EIA process holistically. However, calculating GHG emissions can still be considered a fairly low priority for EIA practitioners; GHG consideration is not specified in EIA legislation from any of the study countries and many of the potential emissions from a development can be (sometimes inadvertently) mitigated against before they even need to be calculated (for example, providing public transport links has the effect of reducing emissions from transport fuels; adding renewable energy sources to a building reduces electricity or gas emissions). It could therefore be questioned why the use of appropriate, consistent, simple and GHG terminology is important, particularly in a comparatively new area of EIA, and why EIA practitioners should consider improving this element of assessments.

Appropriate use of GHG terminology is likely to become more important for developers and EIA practitioners seeking to avoid refusal or reassessment of projects, particularly as understanding of GHG issues increases. Simply because assessments of GHGs are so new and not yet understood, terms can still be used interchangeably and inconsistently. Legal challenges to EIS have already occurred in the USA owing to incomplete, non-existent or inaccurate consideration of the climate change effect of GHG emissions in the USA (Eccleston 2011), and this trend is likely to continue. Projects without consistent and transparent terminology explaining GHG emissions are open to criticism and potentially legal challenges.

Ensuring a consistent approach to the terminology used in association with GHG emissions in EIA, across international borders and involving thousands of developers and practitioners, is clearly not a simple task. GHG terminology in EIA will continue to be affected by popular usage and the way in which the subject is discussed in other industries and in official documentation.

The aim of this study is not to provide a comprehensive list of recommendations to improve the practice of considering GHG emissions in EIA. There are already many resources available, which provide guidance on how GHG emissions should be measured in general terms, not necessarily specific to EIA (including the GHG Protocol (2012) and ISO (2012) standards) alongside specific advice on principles of EIA, both general, such as the IAIA Best Practice Principles (IAIA & IEA 1999) and specifically relating to climate change (IAIA 2012). However, there are some simple steps and additions that could improve the quality and the accessibility of GHG estimation and reporting within EIS. While many of the recommendations could be considered as essentially good practice, it is clear that, in the context of GHG assessment in EISs, these issues occur repeatedly and internationally.

Limit the number of terms used to refer to GHGs in EIS

Using a single term (or single term and abbreviated version) would avoid the confusion seen in many of the study EISs and improve the ability of non-specialists to understand assessments. Although the consistent and simple use of terminology is an acknowledged indicator of good EIA practice (e.g. see criterion relating to this in the EIS quality review scheme on p. 382 of Glasson et al. 2012), the fact that an average of three terms were used in each of the sample EISs demonstrates that this guidance is not penetrating GHG assessments. While a definitive list of appropriate terms for use internationally would simplify the process of comparing global development emissions, this must be a long-term goal owing to regional variations in GHG inventories and assessment methodologies.

Include a thorough definition of terms

Providing information and background to terminology employed to describe GHG emissions allows both specialist and non-specialist readers to understand and comment on the findings. Although most EIS guidelines recommend inclusion of a full list of terms used, these frequently appear only in a glossary for the entire EIS. To ensure that definitions can be used in the appropriate context this information should be included in the chapter(s) where GHGs are mentioned, appreciating that chapters may be read in isolation. In addition, providing guidance to assist competent authorities and those charged with approving developments to understand the terminology, metrics and methods used would allow balanced judgements to be made even in cases where GHG emissions terminology in an EIS is inconsistent.

Provide justification of choice of metric

Including justification and explanation of the metric or the methodology employed to estimate GHG emissions helps the reader judge the appropriateness of the calculation. The relative newness of the issue means that many readers are not yet equipped with the skills to fully understand how and why calculations and assumptions are made, and so need full illustrations of methodology in order to reach balanced decisions on appropriateness.

Ensure consistency

It is essential that estimates, particularly within individual projects, are provided using the same measure of GHG emissions. In the cases where this is not possible, an explanation of why this is the case needs to be included (for example, in those cases where no methodology is available to estimate total GHGs for part of a project, and a simple CO₂ figure is provided instead) as it also highlights the limitations of the study and allows a balanced decision to be reached.

International sharing

The issue of GHG emissions is one of global significance and guidance and approaches must be shared. While international standardization to address this issue is extremely difficult, developing international guidance on terminology based on national GHG inventories, and the work of standards organizations should be the long-term aim for GHG accounting in EIA. While organizations such as IAIA are offering guidance (IAIA 2012), it is important to remember that not all practitioners are part of these organizations, and ensuring that these messages are as widely shared as possible, through both formal and informal lines of communication, is key to improving the robustness of the assessments. Only through a consistent approach will it be possible to make comparisons of local and international GHG emissions and to accurately assess global impacts. Emulating existing models for standardizing approaches to international emissions trading could be used to simplify the process, but consensus will need to be achieved.