Paul Burgess and Richard Halsey, from WYG, provide an EIA Practitioner's view on the use of GHG emissions as a measure of a development project's impact on climate change.
Environmental impact assessments (EIAs) play an important role in supporting the reduction of greenhouse gas (GHG) emissions and ensuring adaptation to our changing climate.
The EIA process has the opportunity to influence projects to optimise energy efficiency performance and limit the negative impact of GHG emissions, but there is a need to enhance the consideration of climate change and consistency of method in EIA practice. To achieve this, the scope of climate change impact assessment within EIA needs to be more clearly defined.
IEMA’s recent guidance on Climate Change Mitigation and EIA provides a useful steer on how to determine the size and significance of climate change effects arising from GHG emissions. It suggests that when evaluating importance of such effects, all new net emissions contribute to a negative effect on climate change. However, there is little supplementary guidance on how to best assess the magnitude and effects of climate change impact in EIA in practice.
Scoping
One the biggest difficulties lies in establishing what “net GHG impact” is in the absence of baseline data or easy access to it. A clearly defined scope and assessment methodology for performing an impact assessment of climate change and GHG emissions, and the relevant supporting evidence required to inform this process, is critical. A comprehensive scope and method will help to ensure local authorities, planners, developers and their advisors all understand what it means to integrate climate change within EIA and to achieving optimum mitigation measures.
Baseline setting
While GHG emissions’ impact at a global scale is important in defining the baseline environment for EIA purposes, the regional and local picture is more important. Emissions at a local level, for example a city or town, in the context of national indicatorsnational indicators and local climate change strategies are especially relevant.
Defining the baseline emissions arising within a site boundary, whether greenfield, brownfield or a renovation project, requires analysis of existing operational uses, which may be diverse and difficult to accurately quantify. In certain cases using local GHG emissions, as defined within local climate change strategies, may provide a sound baseline year and the basis for providing the future baseline for evaluating the significance of impact.
This might not, however, be appropriate for a greenfield site, for example, where agriculture, peat or woodland might be acting as a large carbon dioxide store or sink and would require a bespoke site analysis.
Assessing the hypothetical impact of a typical mixed-use site or housing development, assuming it is built to existing buildings standards, can provide a benchmark development scenario in cases where no development exists.
Impact assessment
Obviously a development which represents a less than 1% increase in local GHG emissions has a lower significance of effect than a development which represents a 20% or 50% increase in emissions. However, in all cases IEMA’s principles require EIA professionals to recognise that the development has significantly increased the local area’s net emissions.
In this context impact magnitude thresholds and corresponding significance-of-effect thresholds need to be clearly defined in the EIA. For practical purposes, the level of detail required in EIAs must be scoped appropriately and, as a minimum, should allow the likelihood of significant climate change effects to be determined, with the limitations clearly stated.
Energy statements can provide useful information on emissions from the heating and powering of developments. However, assessing the impact of embodied (scope 3) GHG emissions is more challenging and such emissions, for example those related to construction, travel and transportation, are less commonly captured as a part of the development assessment process.
Undertaking an impact analysis of the lifecycle GHG emissions of large development projects at the masterplanning stage is not commonplace, but is an emerging practice with a growing evidence base to support it. Frequently the calculation is subjective, particularly when dealing with large projects at the initial stages where materials and plans are unlikely to be defined in enough detail to enable a robust, quantitative appraisal of emissions.
Tools are available for measuring the levels of both direct and indirect emissions (scopes 1, 2 and 3), such as Censa software TBL2, and there are also carbon calculators which look specifically at construction phase GHG emissions, which can be used for useful basic quantification and testing the effectiveness of mitigation options.
It is likely that many developments will have significant net negative effects, given the timeframes for decarbonisation of the UK’s electricity supply, and recent changes to the zero carbon home compliance standards to exclude unregulated emissions.
Summary
For practical purposes, the level of detail required in EIAs must be scoped appropriately and, as a minimum, should allow the likelihood of significant climate change effects to be determined, with the limitations clearly stated.
Setting an appropriate assessment boundary and undertaking benchmarking and assessment, means the effectiveness of mitigation can be seen in the appropriate context. However, to achieve this in a consistent manner across EIAs requires further development of robust and transparent impact assessment processes and supplementary guidance.
This article was written as a contribution to the EIA Quality Mark’s commitment to improving EIA practice. To discuss the themes raised by the article with other environmental professionals visit IEMA’s LinkedIn group.
For more information about the article or its contents contact Paul Burgess, Associate Environmental Consultant, at [email protected]
