Court ruling against Heathrow expansion finds climate pact binding

LONDON • A landmark ruling by Britain's Court of Appeal that stymied plans to build a third runway at Heathrow Airport in London is among the first in the world to measure a state's infrastructure plans specifically against its promises under the Paris Agreement on climate change.

The Heathrow runway case hung on a decade-old British planning law that requires the government to take into account its climate policy in making infrastructure plans.

The government interpreted it to mean that it needed only to consider domestic British legislation related to climate change, not international commitments like the Paris Agreement.

But the court disagreed, saying that the Paris Agreement fell squarely within the boundaries of government climate policy.

The ruling on Thursday threw the expansion of Heathrow into doubt and opened up a new frontier for legal challenges to major projects in Britain and around the world.

While the decision left the door open for Prime Minister Boris Johnson to reformulate the plans and try again, it will set back the runway expansion considerably, prolonging a battle that has raged for years.

It poses a dilemma to a country - a "truly global Britain", in Mr Johnson's words - that is in the midst of severing its strong ties to Europe and looking for new trading partners farther afield.

But analysts said the ruling also relieves Mr Johnson of having to oversee a project that he once opposed so strongly that he once said he would lie down in front of bulldozers to stop it.

And it has halted one part of the government's aviation expansion plans at a moment when any additional flights would jeopardise Britain's own legally binding target of net-zero greenhouse gas emissions by 2050.

While the government said it would not appeal against the ruling, the owners of Heathrow said on Thursday that they would.

Technically speaking, the ruling said only that the expansion plans - drawn up under Mr Johnson's predecessor, Mrs Theresa May - needed to take into account Britain's commitments to help reduce global warming, not that the plans definitely clashed with those vows.

That left room for the government, if it wished, to make modifications to its case for the new runway.

But with Mr Johnson's government already divided on the expansion plan, the ruling made it less likely that he would quickly press ahead, analysts said.

For the Paris accord - already under threat from President Donald Trump, who pulled the United States out of the agreement last year - the ruling sent a strong signal about its potential to serve as a check on domestic policies related to energy and infrastructure.

And legal experts said they expected the ruling to inspire cases in other countries too. "It opens up so many doors, it's almost hard to know which ones to choose," said Mr Tim Crosland, the director of Plan B, one of the groups that brought the legal challenge.

NYTIMES