“We declare clearly and unequivocally that planet Earth is facing a climate emergency,” it states. “To secure a sustainable future, we must change how we live. [This] entails major transformations in the ways our global society functions and interacts with natural ecosystems.”

There is no time to lose, the scientists say: “The climate crisis has arrived and is accelerating faster than most scientists expected. It is more severe than anticipated, threatening natural ecosystems and the fate of humanity.”

The statement is published in the journal BioScience on the 40th anniversary of the first world climate conference, which was held in Geneva in 1979.