Prince William has revealed the five winners of this year's Earthshot Prize

The winners included a project to make South America's Atlantic Forest financially viable as well as a global ocean treaty initiative that aims to conserve marine life.

Football icon Cafu, Olympic gymnast Rebeca Andrade and ex-F1 driver Sebastian Vettel were among those presenting awards at the ceremony - which featured musical performances from Kylie Minogue, Shawn Mendes and Brazilian pop sensation Anitta.

Addressing attendees, William said: "When I founded the Earthshot Prize in 2020, we had a 10-year goal: to make this the decade in which we transformed our world for the better.

"We set out to tackle environmental issues head on and make real, lasting changes that would protect life on Earth."

The prince also hailed the winners - who receive a £1 million grant to continue their eco-work - as the "world's true action heroes".

The 43-year-old royal said: "Their stories are the inspiration that gives us courage.

"And there's a great deal we can learn from their determination and their vision for scale.

"As well as their unyielding belief that we can create a better world. It's no exaggeration to say that they are the world's true action heroes."

William will now travel to Belem for the UN's COP30 climate conference and issued a message of defiance amid pessimism surrounding climate change.

He said: "I understand some might feel discouraged in these uncertain times.

"I understand there is still so much to be done. But this is no time for complacency, and the optimism I felt in 2020 remains ardent today.

"The issues that continue to face our world are a threat to all of us, but when we unite, our momentum is unstoppable."

The Rio ceremony marks the halfway point of the Earthshot Prize initiative and William described how his children have driven home to him about how vital it is to "fix the planet".

The royal - who has Prince George, 12, Princess Charlotte, 10, and Prince Louis, seven, with his wife Catherine, Princess of Wales - said in a film posted on his social media channels: "Now, more than ever, is the time to fix the planet.

"I sat under this oak tree five years ago, soon after we launched The Earthshot Prize. The planet, the only home we have, needed our help, as scientists made it clear that we had to make significant changes by 2030.

"Back then, a decade felt a long time. George was seven, Charlotte five and Louis two; the thought of them in 2030 felt a lifetime away.

"But today, as we stand halfway through this critical decade, 2030 feels very real.

"The Earthshot Prize was founded because this decade matters. 2030 is a threshold by which future generations will judge us; it is the point at which our actions, or lack of them, will have shaped forever the trajectory of our planet."