Ruling gives clarity on assessing cumulative carbon emissions from infrastructure development

Mrs Justice Thornton MBE made the comments in a recent ruling in which she clarified the degree of latitude the secretary of state has when assessing the cumulative impact of carbon emissions – as required to do under environmental law in the UK – when determining applications for development consent for nationally significant infrastructure projects.

The court ruled that the secretary of state for transport did not breach relevant environmental impact legislation despite not carrying out an assessment that compared the combined carbon emissions from three major road projects along the A47 in Norfolk against the UK’s national carbon budgets.

The national carbon budgets are developed under the Climate Change Act 2008 and sit alongside the UK’s climate targets – including the legal commitment to achieve ‘net zero’ greenhouse gas (GHG) emissions by 2050, when compared to 1990 levels.

The case before the High Court concerned whether the transport secretary had, with the approach he had adopted to considering GHG emissions arising from the three A47 projects, met his obligations under the Infrastructure Planning (Environmental Impact Assessment) Regulations 2017. The regulations set out the process of environmental impact assessment (EIA) for development consent for ‘nationally significant infrastructure projects’ under the 2008 Planning Act. The rules require the significant effects of such projects on the environment to be assessed and described in an environmental statement.

The secretary of state calculated and compared the carbon emissions expected to arise from each of the three projects individually against the national carbon budgets, concluding that the increase in emissions anticipated were not significant in each case. He subsequently granted development consent for each of the three projects.

During the examination of the applications for the three projects, the applicant behind the projects provided a figure for the combined emissions from the three projects, however the figure was not assessed for significance against the UK’s national carbon budgets. The secretary of state’s reasons for finding this approach acceptable included that there is no single prescribed approach to assessing the cumulative impacts of carbon emissions; because carbon impacts are not geographically limited to a local area – distinguishing them from other environmental impacts; and because it was appropriate to compare the emissions from each scheme against the national carbon budgets.

However, scientist Dr Andrew Boswell took issue with that approach and raised judicial review proceedings. He argued that the secretary of state was under a legal duty to assess the combined carbon emissions from the three road schemes and that this required the combined carbon emissions from the projects to be assessed against the national carbon budgets.

In its ruling, the High Court said, though, that the question of what impacts should be assessed cumulatively, how the cumulative impacts might occur, whether effects are likely to be significant and how they should be assessed are all matters of evaluative judgment for the secretary of state.

The judge, Mrs Justice Thornton MBE, said there had been an assessment of the cumulative impacts of carbon emissions done by the secretary of state and that while the approach to the assessment had been “unhelpfully expressed” in parts, it was lawful.

Mrs Justice Thornton MBE said the approach accorded with case law and that there was “a logical coherence to the secretary of state’s decision not to compare the combined carbon emissions from local road schemes against the UK’s national carbon target, when those carbon emissions do not have a local geographic limit”. She said the court had to “afford respect” to the “scientific assessment” made that the impact of carbon emissions is not limited to a geographical boundary and considered that the evaluative judgment taken by the secretary of state was within the range of reasonable decisions open to him.

The judge added that while guidance and case law acknowledges “the limited value … of assessing the significance of an individual development project against a national carbon target”, the approach could not be considered unlawful “on the state of present scientific knowledge”. She further considered there had been significant scrutiny applied to cumulative carbon assessment during the examination phase of the development consent process – including consideration given to the points Dr Boswell had raised – but that ultimately the question of how significant the emissions were was a matter of evaluative judgment for the secretary of state.

In reaching her decision, Justice Thornton reflected on the fact that the UK carbon budgets, which reflect the government’s 2050 ‘net zero’ greenhouse gas (GHG) emissions target, “aim to mitigate the greatest effects of climate change by limiting GHG emissions for the whole of the UK economy and society” and that the national targets are not broken down on a sector basis – and that there is specifically no sectoral target for GHG reductions in transport.

The judge said: “Some government policies may result in GHG emissions but they are nonetheless promoted in order to achieve other policy goals. It is the government’s role to determine how best to balance emissions reductions across the entire economy. Any net emissions increase from a particular policy or project is therefore managed within the government’s overall strategy for meeting carbon budgets and the net zero target for 2050, as part of an economy-wide transition.”

Justice Thornton also said that guidance produced by the Institute of Environmental Management & Assessment (IEMA) on evaluating the significance of GHG emissions expressly advised against the approach proposed by Dr Boswell.

The judge added that compliance with such independent guidance does not of itself demonstrate compliance with the environmental regulations. However, she said it is “one 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 EIA”.

Dr Boswell has announced that he is seeking permission to appeal the High Court’s decision.