The Climate Change Committee (CCC) has urged the government to resist the temptation to use past over-performance on meeting its statutory carbon budgets as an excuse to loosen the UK’s future emission reduction ambitions.
In a letter to Graham Stuart, minister of state for energy security, the CCC interim chair Professor Piers Forster congratulates the government for meeting its statutory target to cut emissions in the third carbon budget period, which covered 2018 to 2022.
UK emissions were 391 MtCO2e lower than allowed for in this period, making it the second successive “surplus” that the UK has achieved on its carbon budgets.
The previous surplus from the second carbon budget was carried forward by Theresa May’s government meaning these lower emissions contributed towards the 2018 to 2022 target and fewer fresh reductions were required.
However the most recent surplus is so great that carrying it forward again would allow emissions to actually increase in the fourth carbon budget, which will cover 2028 to 2032, taking the UK away from “a path of continued progress towards its future legal targets”, Forster warns.
Carrying forward the surplus would also dramatically ratchet up the scale of emissions reductions, which the UK would be required to achieve in the subsequent carbon budget, to more than 1,000 MtCO2e.
This scale of reductions, which the letter describes as “huge and impractical”, is double the level projected during this period in the government’s own Carbon Budget Delivery Plan and around 40% higher even than the CCC’s most optimistic scenario, the letter says.
“Carrying forward the Third Carbon Budget surplus would weaken this message, causing uncertainty, and could ultimately result in net zero being more expensive and harder to achieve,” Forster writes.
“The focus now should be on accelerating and broadening emissions reductions, rather than setting conditions that allow for a legally compliant slow-down in progress.”
He adds that while there has been good progress in the decarbonisation of electricity supply, most of the surplus in the third carbon budget was due to predominantly external factors. These include the one-off reduction in emissions seen during the Covid-19 pandemic and the dampening impact of the UK’s GDP being lower than when the targets were drawn up in 2008.
But the biggest factor, accounting for around half of the over-performance on greenhouse gases, was the tighter than anticipated caps in the European Union’s emissions trading system, which the UK is no longer part of.
Carrying forward the emissions reduction surplus would also make it much harder for the UK to meet its 2030 Nationally Determined Contribution emissions pledge at the Glasgow COP26 climate change summit in 2021.
The CCC letter also points out that the carbon budgets are currently based on the UK’s previous goal to cut emissions to 80% of 1991 levels by 2050 not the more demanding net zero target subsequently adopted. This means that emission reduction targets will be increased when the carbon budgets are revised to get the UK on track for hitting net zero in 2050.
Prof Forster said: “The Climate Change Act is working. But the path ahead is tougher and we risk losing momentum if future legal targets are loosened on a technicality. The UK is already substantially off track.”
Dr Simon Cran-McGreehin, head of analysis at the Energy and Climate Intelligence Unit added: “Beating the previous carbon budget was a fluke, with the pandemic and the gas crisis reducing energy demand and masking the UK’s slow progress on insulating homes and building out onshore wind.”