The Prince of Wales has said he wants his environmental Earthshot prize to “change the world for good” over the next decade as he celebrated this year’s winners.

Prince William closed the awards ceremony in Cape Town by calling for people around the world to join the “movement for change”.

Models Heidi Klum and Winnie Harlow, actor Nina Dobrev and artist Tobe Nwigwe announced the £1m ($1.2m) prize winners from each category at the event.

The recipients included an initiative that saved a rare antelope species from extinction and a Kenyan company that uses solar powered fridges to stop harvested crops spoiling.

The fourth edition of the Prince’s annual Earthshot Prize awards was hosted by Grammy award-winner Billy Porter and TV presenter Bonang Matheba.

It supports sustainable, eco-friendly projects from around the world, with each of the five winners receiving £1m to scale-up their innovative ideas to “repair” the planet.

There are five ‘Earthshots’ – or goals: Protect and Restore Nature; Clean Our Air; Revive Our Oceans; Build a Waste-free World; and Fix Our Climate.

Fifteen finalists, from countries including France, Kenya, Indonesia, the UK and Nepal, were competing for their category’s prize pot after being whittled down from 2,500 applicants.

• Protect and Restore Nature: Altyn Dala Conservation Initiative, a project that has saved the critically endangered Saiga antelope from extinction in Kazakhstan

• Clean Our Air: Green Africa Youth Organization, who use behavioural change to help communities clean up waste and build circular waste management infrastructure across Africa

• Revive Our Oceans: High Ambition Coalition for Nature and People, an alliance of at least 119 countries with the ambitious goal to protect 30% of land and oceans by 2030

• Build a Waste-free World: Keep IT Cool, a Kenyan-based company using solar powered refrigeration to help cut harvest waste for farmers

• Fix Our Climate: Advanced Thermovoltaic Systems, an American company that convert excess heat, produced during the making of steel or cement, into electricity

Earlier on Wednesday, the prince praised his wife the Princess of Wales, who is recovering after treatment for cancer, saying she has been “amazing this whole year”.

His wife had not travelled to South Africa and would watch the ceremony at home in Windsor, he said.

“I know she’ll be really keen to see tonight be a success,” he added.

All 2,000 attendees were asked to wear sustainable clothes – either made from recycled materials or a previously worn outfit – and on arrival a host of global stars, made their way down the “green carpet” instead of a traditional red one.

And the prince was no exception, dressed in a second-hand double-breasted Prince of Wales check jacket and white plastic-free fully biodegradable shoes.

Dubbed the prince’s “Super Bowl” moment, the awards were broadcast live across Africa and streamed online. In his closing remarks, the prince said he believed the world could be “rich in possibility, in hope, and in optimism”.

“Our aim was to find solutions to repair our planet and provide real hope for the future.

“We want to make this the decade in which we transform the world for good, one solution at a time, from the ground up,” he said.

When asked earlier about achieving the prize’s green goals in a tough political climate, the prince was positive.

“Everyone wants some hope and some optimism and Earthshot comes with urgent optimism,” he said.

Co-host Harlow said she was honoured to be involved in the project, adding: “This should be something near and dear to everyone’s heart when it comes to taking care of Mother Earth.”

And Klum, who announced the Fix Our Climate category winner, said: “It’s great to spread the word and shine a light on these amazing organisations and what they do.”

Organisers of the Earthshot Prize, which was first awarded in 2021, say they were inspired by former US president John F Kennedy’s Moonshot project, which set scientists the challenge of getting astronauts to the moon and back safely.

The aim of the awards, organisers say, is to celebrate and support those working to provide innovative solutions for climate and environmental issues.

There was a focus on ideas from Africa for this year’s Earthshot Prize, with more than 400 African-led projects nominated and another 350 linked to the continent.

Although Africa generates the fewest emissions for global warming, many of its countries are among the most vulnerable to climate change.

As he spoke of his deep connection to Africa last week, Prince William said he wanted this year’s prize to provide a platform for innovators to bring about change for their communities and inspire young people across the continent.

“Africa has always held a special place in my heart – as somewhere I found comfort as a teenager, and where I proposed to my wife,” he said.

Much of the prince’s visit to Cape Town has focused on young people and the power they have to bring about change.

“Without them the future is looking pretty bleak so these are the game-changers, the innovators, the inventors who are going to make the world a better place for us in future,” he said.

A recent UN report warned that the goals of the Paris agreement to keep global temperatures under 2C while making efforts to stay below 1.5C are now in very serious danger.