21 years ago a schoolboy from Skipton became the first young person ever to address a COP summit.
Shaun addressed world leaders at the age of 17 at COP 6.
Speaking to ITV Calendar at the time he said: "Nobody's ever had that chance before because it was the first time in history that young people have been invited.
"So it was absolutely fantastic."
Today that schoolboy is a family man and he's still an environmental campaigner.
Shaun's mission to save the planet began at primary school. So he's introduced himself to Ruben, a schoolboy in Sheffield, who is also starting young.
"It all started when I saw Greta Thunberg in the news. As I learnt more about it I wanted to do more to help stop it."
Ruben attends Hallam primary, where protecting the environment is now part of the curriculum.
Headteacher Chris Stewart said: "It is their future. Decisions made now really impact on what the world will be like when they get to adulthood. So I think it's really important that our world leaders listen to children."
And the children at Hallam primary agree:
But for Shaun, he thinks he'll be campaigning for at least another twenty years.