This week we saw progressive business and faith leaders making strong commitments that are moving ahead of what world leaders promised today. The leaders of major economies must be bolder than they were today in providing a vision for 100% renewable energy for all.

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'.

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.

There is no definition of terrorism and there is still the reality that one person's terrorist is another person's freedom fighter.

One of the things that I noticed with my own eyes was Nelson Mandela ability to engage with kings and queens and heads of state on the one hand, and his ability to engage with ordinary people, equally comfortably.

Nelson Mandela once said "I can't help it if the ladies take note of me; I'm not going to protest."

I think even though he [Nelson Mandela] was feted and praised as he was, he always was at pains to say, I'm a human being.