Mr Rudd told world leaders at the Copenhagen summit overnight about a book of letters students from O'Connor Cooperative School wrote about climate change. He took the book with him to Copenhagen and read from a letter from Gracie Mitchell during his address.

'' 'Hi,' she wrote. 'My name is Gracie. How old are you?' Gracie continues, 'I am writing to you because I want you all to be strong in Copenhagen ... Please listen to us as it is our future.' I fear that at this conference, we are on the verge of letting little Gracie down,'' he said.

He asked leaders to ask themselves whether, once the meeting was finished, they would be able to sit down and tell their children that they did absolutely everything they could to avoid dangerous climate change.

''Because if we cannot, then we will have failed in our basic duties as leaders of our nations, as fathers and mothers of our children and custodians of our nations' future. The children of the world are watching. They are listening. And history will be the judge of each of us here today,'' he said.