The prince’s words were particularly poignant given the recent activism of 16-year-old Greta Thunberg – addressed a UN one-day summit on the issue of climate change this week.
"This last week, led by Greta, the world's children are striking," the prince said.
"It's a race against time and one in which we are losing. Everyone knows it.
"There's no excuse for not knowing that and the most troubling part of that is that I don't believe that there's anybody in this world that can deny science."
On a more personal note, Harry then opened up about how Botswana had offered him refuge after the death of his mother.
“Fifteen years I’ve been coming here, it’s a sense of escapism, a real sense of purpose … I have some of my closest friends here over the years," he said.
"I came here in 1997, 1998, straight after my mum died, so it was a nice place to get away from it all.
"But now I feel deeply connected to this place and to Africa."
Harry’s powerful speech comes just weeks after he and Meghan were heavily criticised for their use of private jets.
