The first five £1 million winners of Prince William's Earthshot Prize have been announced at a star-studded ceremony in London, with a country, a city and a host of innovative projects among the recipients.
The Duke and Duchess of Cambridge arrived on the green carpet in an electric car for the event at Alexandra Palace, wearing clothes they have worn on other engagements in the past, setting the tone for what was described as the most sustainable event of its kind.
In a video filmed inside a pod on the London Eye, Prince William described how "the planet is at a tipping point… this is the decisive decade and time is running out".
In a speech later in the ceremony, he called on the next generation to demand more, saying: "I want to say something to all the young people watching tonight.
"For too long, we haven't done enough to protect the planet for your future - but Earthshot is for you.
"In the next 10 years we are going to act. We are going to find the solutions to repair our planet.
"Please keep learning, keep demanding change, and don't give up hope. We will rise to these challenges."
But as well as being a stark warning about the dangers of climate change, the television event was primarily a celebration of innovation and the inspiring projects around the world tackling some of the world's most pressing environmental problems.
Over the next decade, £5 million prizes will be awarded every year in five specific areas.
This year's winners were:
• Protect and Restore Nature: The Republic of Costa Rica - A scheme paying local citizens to restore natural ecosystems that has led to an incredible revival of the rainforest
• Clean our Air: Takachar, India - A cutting-edge technology to create fuel from agricultural waste and put a stop to the global air problem of crop burning
• Revive our Oceans: Coral Vita, Bahamas - An innovative approach to coral farming that can help restore our world's dying coral reefs faster than any traditional method
• Build a Waste-free World: The city of Milan, Italy - A city-wide initiative that has dramatically cut waste while tackling hunger.
• Fix our Climate: AEM Electrolyser, Thailand/Germany/Italy - A green hydrogen technology developed to transform how we power our homes and buildings.
Prince William decided in 2018 there was too much pessimism in the climate debate, and wanted to inject some optimism.
William and his team came up with the Earthshot prize, inspired by JFK's Moonshot Project, with the hope of inspiring the innovators of the future.
Coldplay recorded a performance outside, powered by 60 cyclists, with stars such as Ed Sheeran, Emma Watson, Sir David Attenborough, Dame Emma Thompson and footballers Dani Alves and Mo Salah also joining the royal couple to help deliver the message to a global audience.
Actress Thompson said: "We're in the middle of the disaster. We're right in it, we're in the forest fires, we're in the tsunamis, we're in everything right now, it's not about the future, it's happening now.
"And that's where I like to read as much as I can so I know what's going on and what will happen and then just be as active as possible."
The Earthshot awards will be held every year over the next decade and at the end of this year's ceremony, Prince William confirmed the next event will take place in the US.