Bravery will be needed to offset extra damage to the climate

Expanding Heathrow would certainly result in increased carbon dioxide emissions and that could put the UK further off track to meet its climate goals.

- Fiona Harvey

The government claims it can offset that by investing in research on new low-carbon fuels for aircraft, and electric planes. But the technology is decades away, if it ever reaches commercial scale, making it certain that any new runway would be used by the same kerosene-fuelled, high-carbon aircraft that we have today.

The Climate Change Committee, the government's statutory adviser on net zero, has warned repeatedly that airport expansion would breach the UK's carbon budgets, which are set years in advance on a pathway to meet the goal of net zero emissions by 2050.