The High Court has delivered an important judgment relating to the environmental assessment of cumulative carbon impact of road schemes. National Highways has been promoting a series of improvements to the A47 Trunk Road via the NSIP process. The Secretary of State granted development consent orders for three of the schemes.
The Claimant, Dr Boswell, issued proceedings in the High Court challenging the assessment of cumulative carbon impacts that had been undertaken in each of the schemes alleging that there had been no cumulative impact assessment undertaken, since only the scheme emissions had been compared against the national carbon budgets. The Claimant contended that the impact of a number of local schemes together with the scheme should have been compared against the national carbon budgets.
The Defendant and National Highways argued that since the impacts of GHG emissions do not have a geographical limit, the Defendant’s decision not to undertake comparison of combined emissions against the national carbon budgets was logical, reasonable and lawful. Indeed, Dr Boswell’s approach was contrary to the relevant advice from IEMA which states:
“All global cumulative GHG sources are relevant to the effect on climate change and this should be taken into account in defining the receptor (the atmospheric concentration of GHGs) as being of ‘high’ sensitivity to further emissions. Effects of GHG emission from specific cumulative projects therefore in general should not be individually assessed as there is no basis for selecting any particular (or more than one) cumulative project that has GHG emission for assessment over any other.” (emphasis added).
The Court concluded that:
- The question of what impacts should be addressed cumulatively; how the cumulative impacts might occur; whether the effects are likely to be significant and if so how they should be assessed are all matters of evaluative judgment.
- The decision makers chose to assess the significance of carbon emission against a national target (UK carbon budgets). Other benchmarks were considered but discounted. The benchmark for the assessment of significance was a matter of judgement for the decision maker.
- The use of national carbon budgets as a benchmark for the assessment of carbon emissions has been confirmed as a lawful approach (R (GOESA) v Eastleigh Borough Council).
- The decision makers also proceeded on the basis that there is no geographic limit to the impact of GHG emissions. Their impact is on the global atmosphere. That is a scientific assessment to which the Court affords respect (R (Mott)v Environment Agency).
- In circumstances where the significance of carbon emissions is being assessed against a national target and the impacts of GHG emissions do not have a geographical limit, there is a logical coherence to the Secretary of State’s decision not to undertake a comparison of combined emissions against the national target. The reason for this is explained in the IEMA Guidance (see above).
- Whilst compliance with independent guidance does not, of itself, demonstrate compliance with IEIA Regulations, it is a legitimate way for the Court to assess the exercise of judgment in circumstances where there is no single prescribed approach to the assessment of cumulative carbon impacts or to gauging the significance of the climate impacts of a development project in the context of Environmental Impact Assessment.
- There is no scientific rationale for the selection of a particular collection of local schemes for comparison against a national target.
- The fact that there may be other approaches to the assessment of cumulative impacts, does not take the Secretary of State’s approach outside the range of reasonable responses available to him as the decision maker, or mean that it was based on flawed reasoning.
- The Court was not persuaded that his approach to the assessment of cumulative carbon emissions was unlawful and/or in breach of the IEIA Regulations.
The judgment may be accessed here.
Reuben Taylor KC appeared for National Highways.
