In a rare win for environmental campaigners, the third runway planned for Heathrow Airport has been blocked after being ruled illegal by the Court of Appeal. Lords Justice Lindblom, Singh and Haddon-Cave said a new runway would be at odds with the government's commitments on climate change (currently, to achieve net zero emissions by 2050).This is the first court ruling ever to be informed by the Paris climate agreement, and sets an encouraging global precedent. If there's no third runway allowed at Heathrow, we could start seeing a stop being put to other environmentally-destructive initiatives across the world.There are still ways for the government to get around the ruling – for example, appealing the decision in the Supreme Court – but Boris Johnson has historically been against the expansion, because his Uxbridge and South Ruislip constituency would be one of the areas most affected by it.Though it feels like a small part of an uphill battle, this ruling is a symbol of the value of protest and people power. It's the sort of top-level decision that movements like Fridays for Future and UKSCN have long rallied for, and could signal a sea change in the seriousness with which climate change is taken by the highest offices in the UK and beyond. Point being: climate protesting works.Speaking to the Guardian, Tim Crosland from Plan B – the legal charity that brought the challenge – said: "The court ruling is bad news for all businesses and investors in the carbon economy, who will have to factor in the increasing risks of legal challenges. But really, it is good news for everyone, since all of us – including businesses and investors – depend on maintaining the conditions which keep the planet habitable."