- New analysis finds that a third runway at Heathrow would blow a hole in the UK's ability to meet legally binding climate targets.
- The case for aviation expansion hinges on sustainable aviation fuels and greenhouse gas removals but there is currently no evidence that these technologies can support the scale of expansion envisaged by the government.
- The climate scientists behind the report recommend the government rejects plans for a third runway.
There is no credible scenario in which expansion at Heathrow can go ahead without blowing a hole in the UK's legally binding climate targets, new modelling published by the Tyndall Centre for Climate Change Research at The University of Manchester reveals today.
The report, commissioned by the environmental justice organisation Friends of the Earth, provides the first detailed analysis of whether Heathrow expansion is compatible with the UK's legal carbon budgets.
Recent approvals of airport expansion at Gatwick, Stansted Luton and many other locations mean that UK aviation is already projected to exceed its share of the Seventh Carbon Budget (2038-42) by between 21 and 50%, depending on how much sustainable aviation fuel materialises. That is before any Heathrow expansion takes place.
The analysis concludes that the two technologies relied upon to enable passenger growth or airport expansion to fit within carbon budgets - Sustainable Aviation Fuels (SAF) and Greenhouse Gas Removals (GGR) - are not even close to being on track for sufficiently capacity within the required timeframe.
The report concludes that Heathrow expansion cannot credibly meet the UK's climate targets thanks to three key findings:
Aviation emissions: The UK's aviation sector will already exceed its share of the Seventh Carbon Budget by around 40%, even before Heathrow expansion is considered. The research highlights how even the government's own modelling reaches a similar conclusion.
Sustainable Aviation Fuels (SAF): Based on existing evidence SAF would be unable to close the emissions gap. Even optimistic deployment of this technology would leave aviation above its carbon budget share. Previous studies have shown that current SAF production methods face major structural constraints or compete with agriculture for land and water, just as farmers have experienced what could be the worst harvest on record and are already warning about the impact of the climate crisis on food production.
Greenhouse Gas Removals (GGRs): GGR describes methods that remove carbon dioxide from the atmosphere and stores it long-term, such as bioenergy with carbon capture and storage. The report highlights how global GGR deployment is significantly off track and that no engineered removal plants are operating yet in the UK. Despite this, aviation emissions modelling heavily relies upon future potential GGR to offset additional emissions. Even before any airport expansion is taken into account aviation is the biggest projected user of GGR capacity. On top of this, these scenarios all depend on SAF pulling its weight; if SAF fails to deliver, even more GGR will have to be deployed. The report concludes that the building capacity for more aviation demand before large scale GGR facilities are operational is inconsistent with taking climate targets seriously.
Non-CO₂ impacts are not accounted for: Aviation's full warming effects are not captured within carbon budgets. Non-CO₂e impacts including from nitrogen oxides and contrails, account for around two-thirds of aviation's climate warming and should be incorporated into future climate targets.
What do the researchers say?
The lead researchers, Dr Lois Pennington, Professor Alice Larkin and Dr Chris Jones recommend decisionmakers reject any proposed expansion at Heathrow Airport.
Dr Lois Pennington, Research Fellow at the Tyndall Centre said:
"Every aviation scenario the UK Government has published overshoots the carbon budget Parliament has legislated, before a third runway at Heathrow is even taken into account.
"Our analysis shows that aviation cannot continue to grow if the sector is to make a proportionate contribution to meeting the UK's carbon budgets. Sustainable aviation fuels and carbon removals can contribute to limiting aviation emissions, but there is currently no evidence that these technologies can support the scale of aviation expansion envisaged by the government.
"Further aviation expansion carries a significant risk of exacerbating climate impacts by relying on the growth of technologies that are unlikely to materialise in the timescale needed.
"The UK is experiencing another exceptionally hot summer, while record-breaking severe wildfires have burnt across Western Europe. The Government must reassess the case for expansion. Climate policy must be grounded in what we can demonstrate and evidence, rather than what we hope may become possible."
Mike Childs, head of policy, science and research at Friends of the Earth, said:
"After this summer of record-breaking heat and nearly 3,000 excess deaths, this third runway is the equivalent of pouring petrol on a raging wildfire.
"The evidence is clear: there is no route where expansion at Heathrow can be in line with our legally binding climate targets. Suggesting that sustainable aviation fuel and greenhouse gas removals can enable airport expansion is simply trying to pull the wool over people's eyes.
"The government has a choice: commit to taking action on the climate seriously, reject Heathrow expansion and constrain excessive flying, or abandon the UK's climate targets and future generations by giving the third runway the go ahead.
"With a weak economic case to support expansion set against a huge impact on the climate and communities, this is the opportunity for the new Prime Minister to truly set a precedent by turning his back to corporate lobbying and say no to a third runway at Heathrow."
The public consultation on the government's Heathrow Expansion National Policy Statement (HENPS) closed earlier this week on Tuesday 1 September, the same day that members of parliament returned from recess to scrutinise the proposal.
Friends of the Earth and the Tyndall Centre are calling on the UK Government to reject Heathrow expansion and ensure future aviation policy remains consistent with legally binding carbon budgets under the Climate Change Act.
