Review of greenhouse gas emissions in SEA and EIA

The implementation of the Climate Change (Emissions Reduction Targets) (Scotland) Act 2019 has set a new climate change target for reducing emissions that aims to bring Scotland’s emissions to net-zero by 2045. Achieving this target will require a sound understanding of likely greenhouse gas (GHG) emissions (or reductions) arising from national, strategic and project level decision-making.

The requirement to consider the impacts of a plan, programme or strategy (PPS) or proposed development on GHG emissions is captured as part of a wider assessment under the Strategic Environmental Assessment (SEA) and Environmental Impact Assessment (EIA) regimes where relevant. This research seeks to review current practice in considering greenhouse gas (GHG) emissions as part of these processes, focusing in particular on:

  • methodologies used to assess GHG emissions impacts
  • the level of detail included in these assessments
  • how these emissions are reported and communicated

The project also records observations on the effectiveness of the approaches taken to reporting and communicating these findings.

Key findings

Strategic Environmental Assessment (SEA)

We reviewed ten Environmental Reports prepared between 2015 and 2020 for the SEA case studies. The case studies included local development plans, local authority level plans and strategies for climate change, renewable energy, transport, woodland, a sub-local tourism strategy, and two national level case studies covering climate change and a circular economy. Based on this review we identified that:

  • The environmental baseline information included a range of data relevant to GHG emissions.
  • An overlap between topic areas as part of the SEA process often results in information relevant to GHG emissions being considered and reported under other SEA topic headings but not being explicitly used to inform the assessment of GHG emissions impact (and not captured under the associated SEA heading of ‘climatic factors’). As a result GHG emissions are not comprehensively reflected in a single specific area of the assessment process.
  • Reporting under a single SEA heading of ‘climatic factors’ results in a lack of distinction between reporting of impacts on reducing GHG emissions (mitigation) and actions to adapt to the effects of climate change (adaptation).
  • The majority of the Environmental Reports did not clearly set out the basis for considering the significance of the impact on climatic factors, for example whether significance was related to the baseline, local or national targets.
  • The case studies did not use specific tools (for example carbon calculators) to assess GHG emissions; instead assessment approaches adopt a qualitative approach that use the SEA scoring system[1] and associated descriptive text, and indicate a direction of travel in GHG emissions (e.g. increase or decrease).

Environmental Impact Assessment (EIA)

We reviewed ten Environmental Impact Assessment Reports (EIA-R) or equivalent, prepared between 2009 and 2019. The case studies cover a wide range of projects across a number of different consenting regimes and include wind farm developments, road construction, mining, forestry, marine infrastructure, mixed use and a recreational development. Based on this review we identified that:

  • Although the case studies were intentionally selected because they contained some level of assessment of GHG emissions, the majority (eight out of ten) did not provide baseline data on GHG emissions. In line with IEMA guidance, some case studies provided justification for this by stating that the baseline is considered to be ‘nil’ as the site is currently undeveloped, meaning that there are no associated emissions.
  • Two of the case studies included GHG emissions data at a national level, reflecting the wider impacts of the developments beyond the site boundary.
  • The majority of the case studies (seven out of ten) included quantified assessment information for the construction phase of the development, commonly covering direct, indirect and embodied emissions. These examples often include the quantification of emissions such as embodied carbon within construction materials, the associated transport emissions from construction material delivery and onsite plant fuel usage.
  • Six of the ten case studies included some degree of quantification of operational GHG emissions. Only four of these fully covered direct, indirect and embodied emissions.
  • Despite the guidance advocating a life-cycle approach, the assessment of GHG emissions at the decommissioning phase is the least well documented. This is often scoped out on the justification that the emissions cannot be accurately predicted due to the lifespan of the project.
  • The majority of the case studies reviewed employed some form of tool as part of the assessment. Most commonly such an approach was used to record either embodied GHG emissions in the required construction materials or GHG emissions associated with transport movements.
  • Inclusion of quantified GHG emissions data is more likely where relevant quantified information is already available for the project (e.g. material quantities or vehicle movements) that can be used to determine corresponding GHG emissions.
  • The approach to determining the level of significance of the GHG emissions arising from a project varies. In eight of the case studies a lack of baseline data prevented this being used as the basis for determining impact significance. A lack of regional or local GHG emissions targets also means that there are no meaningful benchmarks against which to judge significance.
  • Where GHG emissions data is provided this is often clearly communicated, with the ‘payback’ approach often adopted for wind farms as an example.

Future implications

The SEA case studies highlight that significant effort is put into the qualitative assessment of GHG emissions in SEA. However, there is scope for the various elements of the assessment process (baseline, assessment questions, definition of significance and monitoring) to be joined up more comprehensively.  The qualitative nature of the plans, policies and strategies being assessed defines the approach to the assessment of GHG emissions.

There is evidence of good practice with respect to the quantification of greenhouse gases in EIA from the case studies. Some of these examples have used supporting tools which could be more widely applied. The express consideration of greenhouse gases in EIA only became a formal requirement in 2017. EIA practitioners are also continuing to gain more experience in the assessment of GHG emissions impacts.

The declaration of a climate emergency, commitment to achieving net zero emissions and local authority level actions being taken to respond to this, is likely to lead to an increase in i) the collection of relevant data, ii) co-ordination of existing data, which could inform these assessment processes, and iii) expertise and engagement of decision makers and consultees in SEA and EIA scoping and development.