I was 15 years old when I first heard the name Mandela, or Madiba, as he is fondly known in Africa. In apartheid South Africa he was public enemy number one. Shrouded in secrecy, myth and rumour, the media called him 'The Black Pimpernel'.

The city of Copenhagen is a climate crime scene tonight, with the guilty men and women fleeing to the airport in shame. World leaders had a once in a generation chance to change the world for good, to avert catastrophic climate change. In the end they produced a poor deal full of loopholes big enough to fly Air Force One through.

[Nelson] Mandela was very keen not to be understood as an exceptional person.

My final advice for young people is to not wait for leadership from adult politicians. Step forward today, because our current leaders are denying the dire reality we are facing. Leadership can come form anywhere.

The reality is today most of our political leaders want to be treated as gods and semi-gods, from the security details to the fuss around them and so on.

You know how they say, 'What happens in Vegas, stays in Vegas?' What happens in the Arctic doesn't stay in the Arctic.

Currently, we allow our political and business leaders to get away with murder. Now is the time to change that. We need direct liability for those who are destroying our future and this planet. We need fast, profound and systemic change. History only moves forward when courageous people get up and act. That's why I support this citizens' initiative to recognise ecocide as the crime it is.