A major report from the Tyndall Centre for Climate Change Research at the University of Manchester has concluded that expanding Heathrow Airport is incompatible with the UK’s legally binding climate targets. The study, commissioned by the environmental group Friends of the Earth, examined whether Heathrow expansion could align with the UK’s carbon budgets. It found that existing expansions at other airports—such as Gatwick, Stansted, and Luton—are already projected to cause aviation emissions to exceed the UK’s share of the Seventh Carbon Budget (covering the years 2038–42) by 21% to 50%, depending on the availability of sustainable aviation fuel. These figures are calculated without considering any additional growth at Heathrow. The report highlights that sustainable aviation fuels (SAF), which are designed to reduce emissions from air travel, and greenhouse gas removals (GGRs), which aim to capture carbon from the atmosphere, are not on track to meet the required capacity within the necessary timeframe. Based on three key findings—aviation emissions, the limited capacity of SAF, and the current lack of GGR infrastructure—the analysis concludes that Heathrow expansion cannot meet the UK’s climate targets. The report also points out that non-CO₂ effects of aviation, such as nitrogen oxides and contrails, are not fully accounted for in carbon budgets, yet they contribute significantly to climate warming. Lead researchers Dr. Lois Pennington, Professor Alice Larkin, and Dr. Chris Jones recommend that decision-makers reject any proposed expansion at Heathrow. They argue that the UK government’s published aviation scenarios already exceed the carbon budget even before considering a third runway at Heathrow. The researchers emphasize that there is currently no evidence that sustainable aviation fuels and carbon removals can support the scale of aviation expansion envisioned by the government. They also note that further expansion poses a significant risk to climate goals by relying on technologies that are unlikely to materialize in time. Mike Childs, head of policy, science, and research at Friends of the Earth, stated that the evidence is clear: Heathrow expansion cannot align with the UK’s legally binding climate targets. He criticized the idea that sustainable aviation fuel and greenhouse gas removals can enable airport expansion, calling it an attempt to mislead the public. Childs urged the government to either reject Heathrow expansion and limit excessive flying or risk abandoning the UK’s climate targets and future generations by approving a third runway. The public consultation on the government’s Heathrow Expansion National Policy Statement (HENPS) closed on September 1, the same day that members of Parliament returned from recess to scrutinize the proposal. Friends of the Earth and the Tyndall Centre are urging the UK government to reject Heathrow expansion and ensure future aviation policy aligns with the legally binding carbon budgets outlined in the Climate Change Act.