But although his memories of the famous Day of Rage, on May 21, 1971, are still vivid, he says it is almost impossible to imagine something similar happening today.

And it is not entirely the fault of an apathetic youth more intent on getting high-paying jobs than standing up for what they believe in.

The professor of public ethics at the Centre for Applied Philosophy and Public Ethics will be speaking at a youth forum on Saturday as part of the centenary's National Youth Week celebrations, where he will be running a workshop on activism.

"We hear a lot of commentary about the apathy of modern youth, and how university campuses are not what they used to be, that students are far too focused on getting their degrees and getting well-paying jobs rather than engaging in activities that might result in social change," he said. "There's a lot of truth in that, but there are still a substantial number of angry and active young people who are determined to make the world a better place. But they face a social environment in which it's much more difficult to mobilise young people and old people."

Professor Hamilton is on the board of the Climate Change Authority, and said this was the area where most youth activism was directed. "That issue of climate change throws up all sorts of difficulties and imponderables for activists. It is complex, but at another level it's very simple."

But although the imminent threat of climate change has long been acknowledged, he said, our political system had failed to respond with anywhere near the urgency required.

"In a way, the general public collaborates in that. Why aren't people massed on the streets, surrounding coal-fired power plants … demanding immediate action?" he said. "Why is it that when the Labor government introduces a very mild carbon pricing policy, the outrage is all on the other side? In the face of that, you'd have to realise that the situation is far more difficult than it was in the days of the Vietnam War."

He said the way young people engaged in political discourse had changed, and was partly due to the political environment they had grown up in, a homogeneous system that presents no alternative world view. "The main political parties have converged on essentially the same understanding of the world and the same set of policies, a neo-liberal conception of the world where even social democracy is regarded as radical nowadays," he said.

"That means if you want to exercise influence, the avenues for doing so are very highly constrained and conservative, and it's all about trying to shift public opinion, it's all about lobbying and media releases and focus groups, and that whole style of politics which the main parties engage in and which many young activists believe is the only way to operate."

His message would be simple, he said - youth activists needed to be prepared to take risks. "Youth activists … have to step outside of the narrow parameters set by the existing political system," he said.

He will be joined on Saturday by anti-coal activist Jonathan Moylan, who issued a fake ANZ press release saying the bank had withdrawn funding for Whitehaven's coalmining project at Maule's Creek.

The Centenary Youth Week forum No Need To Be Told is on Saturday April 13, 4pm-8pm in Civic Square. For more information, visit www.canberra100.com.au.