UK carbon budget delivery plan ruled unlawful

The carbon budget delivery plan (CBDP) was fixed by the UK government on 30 March 2023 in response to a court order from the High Court. The 2023 CBDP represented an update of the government’s plans for remaining on track with its legally-binding climate change commitments after its 2021 net zero strategy was deemed unlawful by the High Court in a judgment handed down in summer 2022.

The 2023 CBDP contains proposals and policies that the government claimed would allow the UK to fall within greenhouse gas (GHG) emissions allowances provided for in three five-yearly carbon budgets, up to when the last of those carbon budget period ends, in 2037. The decision to adopt the CBDP was taken by then secretary of state for energy security and net zero, Grant Shapps, under duties the secretary of state has to prepare proposals and policies for meeting carbon budgets under UK law. Those duties are set out under section 13 of the Climate Change Act 2008.

However, like the net zero strategy, the CBDP was challenged before the courts by climate campaigners, including the Friends of the Earth and ClientEarth groups.

In a ruling on Friday morning, the High Court upheld four of the five grounds of complaint the campaigners raised – including finding that it had been “irrational” for Shapps, in signing off on the CBDP, to conclude that the proposals and policies contained within the plan will enable the carbon budgets to be met.

Mr Justice Sheldon held that the secretary of state’s decision had been based on “the assumption that each of the proposals and policies would be delivered in full”. The judge considered that he had therefore made the decision “on the basis of a mistaken understanding of the true factual position”, given the government’s own assessment of the risks and uncertainties in delivering the full benefits of a number of the policies. His decision to endorse the plan was “simply not justified by the evidence”, the judge said.

David Thorneloe of Pinsent Masons, an expert in public and administrative law, said: “It was not the High Court’s task to say whether it approved of the government’s climate change policies, and it rightly offered no view on this. The task given to the court by the Climate Change Act was to scrutinise the government’s decision-making process, to ensure that there was a rational, sound evidential basis for its conclusion that it is on course to meet its net zero target.”

“The judgment highlights the risk of optimism bias in the advice that officials give to their political masters. In this case, officials sought to place a positive gloss on their advice to ministers by emphasising that the net zero target could be achieved if there was an assumption that every government measure in the report would be delivered in full. This ultimately led to the court’s intervention, as it was an assumption that could not be backed up by the government’s own evidence,” he said.

“The case also highlights the importance of document disclosure in judicial review litigation. Although Friends of the Earth failed in its argument that the government should publish its assessments of its policy delivery risks, the government was required to disclose these assessments to the court and the other parties, because of their relevance to its decision-making. Ultimately, this led to publication in the judgment of some key risk assessments, allowing Friends of the Earth to secure some of the public scrutiny they were aiming for,” Thorneloe said.

The court has not made any order yet as to what action the government will now need to take to update the 2023 CBDP.