The Duke of Cambridge set himself a challenge to help in the fight against climate change, so that he can "look my children in the eye and say that I did my bit" as he he revealed how an incredible trip sparked his idea for The Earthshot Prize.
Jason Knauf, CEO of The Royal Foundation said: "The challenge The Duke set himself was 'What is the maximum positive personal contribution I can make in the next ten years in the fight against climate change? What am I going to do in the next decade that means I can look my children in the eye and say that I did my bit?' Every aspect of the Prize bears the stamp of his contribution."
In an introduction to Earthshot: How to Save Our Planet, Prince William speaks about the early conversations that led to the creation of The Earthshot Prize and why President John F. Kennedy's Moonshot programme, which united millions of people around the goal of reaching the moon, was behind his inspiration.
The future King says the crucial moment was when he made an early-morning trip to try to catch a glimpse of black rhino in Namibia.
READ: Kate Middleton returns to work with moving visit - best photos
WATCH: Prince William sets time and place for his inaugural Earthshot Prize awards
William writes in the book's introduction: "The rich wildlife that I saw thriving on that visit struck a real chord. The community conservancy model is a prime example of how a simple, positive solution can have wide-reaching benefits for both humans and nature.
"Most importantly of all, it is a success story that can be replicated and scaled. I wanted to find a way to bottle that innovation and community spirit and mass-produce it globally."
The Duke said he saw his ambitious project as a means to turn around pessimism about the planet’s future, as he believed at the time there was "a real risk that people would switch off, that they would feel so despondent, so fearful and so powerless".
He added: "I started thinking about what to do to change the equation to something else: urgency + optimism = action. The most famous example of using optimism to rise to a great challenge is the Moonshot…"
William launched The Earthshot Prize in October 2020, which aims to inspire collective action around our unique ability to innovate, problem solve and ultimately repair our planet.
MORE: Prince William and Kate Middleton send birthday wishes to Prince Harry
MORE: Kate Middleton reveals George, Charlotte and Louis' shared interest with dad William
Earthshot: How to Save Our Planet, £16, Amazon
Every year from 2021 until the end of the decade, winners in five categories will each receive £1 million to be used for their solutions after being picked by a judging panel consisting of the Duke and leading figures.
They will be recognised for new ideas, technologies, policies or solutions which tackle one of the five Earthshots: Protect and restore nature; Clean our air, Revive our oceans; Build a waste-free world; and Fix our climate.
On Friday, William announced the inaugural 15 finalists for the Prize on YouTube. Of these 15 finalists, five winners will be announced during an awards ceremony on 17 October from London's Alexandra Palace.
Among the finalists are a teenager from India who has designed a solar-powered ironing cart, the nation of Costa Rica, which has pioneered a project paying local citizens to restore natural ecosystems, and a Chinese app that allows its citizens to hold polluters to account.
There are no UK finalists but organisers believe homegrown talent will feature in the environmental award in future years.
In a video message to launch the finalists, William said: "The ambition, quality and range of submissions has been amazing, and should fill us all with optimism and hope that our goals for this decisive decade are achievable."
Earthshot: How to Save our Planet will be released on 30 September.
HELLO!'s selection is editorial and independently chosen – we only feature items our editors love and approve of. HELLO! may collect a share of sales or other compensation from the links on this page. To find out more visit our FAQ page.
Make sure you never miss a ROYAL story! Sign up to our newsletter to get all of our celebrity, royal and lifestyle news delivered directly to your inbox.