Prince Harry has strongly criticised climate change deniers, only days after schoolgirl activist Greta Thunberg accused world leaders of failing to act.
The British royal's comments were made during a brief visit to Botswana, and he described how the nation was a refuge for him following the death of his mother, Princess Diana.
His dad Prince Charles took Harry to Africa after Diana was killed in a Paris car crash in 1997, a decision he said allowed him "to get away from it all".
Harry, who was highlighting a forest conservation project in the northern town of Kasane, said there was "undeniable science and facts" behind climate change, and he could not understand how anyone, from children to leaders, denied the science.
Speaking on the banks on the Chobe River, where he helped young children plant trees, Harry highlighted the activism of Ms Thunberg, who has sparked the global climate strike movement and addressed a UN one-day summit on the issue this week.
"This last week, led by Greta, the world's children are striking," he said.
"There is an emergency, it's a race against time and one in which we are losing, and everyone knows it.
"There is no excuse for not knowing, that I think the most troubling part of it is - I don't believe there is anybody in this world that can deny science, undeniable science and facts.
"Science and facts that have been around the last 30, nearly 40 years, and it's only getting stronger and stronger.
"Genuinely I don't understand how anyone in this world, whoever we are, you, us, children, leaders, whoever it is, no one can deny science."
The prince's climate change stance was criticised after he reportedly took four private jet journeys in 11 days during the summer with Meghan.
In response, Harry said he spent "99pc of my life" using commercial flights but occasionally needed to ensure "my family are safe".
Harry knows Botswana well, and he reportedly whisked his wife there in 2017 to mark her 36th birthday - a year after their love blossomed in the nation during a brief visit soon after they met on a blind date.
Meghan's engagement ring not only features diamonds from the personal collection of Diana, but a stone from Botswana.