Others found hope in the climate activism and awareness of younger generations, and in the finding that each extra tenth of a degree of warming avoided protects 140 million people from extreme temperatures.

“I regularly face moments of despair and guilt of not managing to make things change more rapidly, and these feelings have become even stronger since I became a father,” said Henri Waisman of France’s Institute for Sustainable Development and International Relations. “But, in these moments, two things help me: remembering how much progress has happened since I started to work on the topic in 2005 and that every tenth of a degree matters a lot—this means it is still useful to continue the fight.”

Peter Cox of the University of Exeter added: “Climate change will not suddenly become dangerous at 1.5°C—it already is. And it will not be ‘game over’ if we pass 2°C, which we might well do.”

Many of the scientists who still saw a hope of keeping 1.5°C alive pinned it on the speeding rollout and falling prices of climate-friendly technologies like renewable energy and electric vehicles. Also on Wednesday, energy think thank Ember reported that 30% of global electricity came from renewables in 2023 and predicted that the year would be the “pivot” after which power sector emissions would start to fall. Experts also said that abandoning fossil fuels has many side benefits such as cleaner air and better public health.