Heathrow’s third runway faces a climate test

UK climate advisers have cautioned that the expansion of London's Heathrow Airport may conflict with the country's legally binding climate goals. The Climate Change Committee (CCC) report emphasizes that the aviation sector must achieve net-zero emissions by 2050 if the airport's proposed third runway is to comply with UK climate targets.

Nigel Topping, chair of the CCC, highlighted that these conditions do not currently exist. Heathrow recently unveiled its £49 billion expansion plan, which includes the long-awaited third runway. The government approved the plan after protracted legal battles and opposition from environmentalists and local residents.

The recent summer heatwave, the warmest on record for the second consecutive year, underscores the urgency of addressing climate change. Every tonne of greenhouse gas emissions exacerbates the situation, Topping added.

Despite opposition, the Labour government, led by Prime Minister Andy Burnham, reaffirmed its support for the expansion. Finance Minister John Healey argued that the project would stimulate economic growth. Aviation remains a highly carbon-intensive form of transport, difficult to decarbonize, according to a March 2025 briefing by the UK parliament's independent information service.

Heathrow's expansion would nearly double its capacity to accommodate up to 150 million passengers annually. This proposed expansion is rare in Europe, where countries are divided between efforts to reduce greenhouse gas emissions and support strategic sectors experiencing growing demand. The UK has pledged to cut greenhouse gas emissions by 87 percent by 2040 and achieve net-zero emissions by 2050.

The CCC proposed a net-zero pathway for aviation based on the polluter pays principle. This approach combines direct emissions reductions with investments in technological solutions, such as carbon capture, for the aviation sector.