In a video message released to mark the announcement of this year’s finalists, he reflected on the past five years.
“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,” said Prince William.
“But today, as we stand halfway through this critical decade, 2030 feels very real.
“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.”
He added: “The people behind these projects are heroes of our time, so let us back them. Because, if we do, we can make the world cleaner, safer and full of opportunity – not only for future generations, but for the lives we want to lead now.”