Bob Geldof has been ringing alarm bells and tackling humanitarian crises for two and a half decades, but his latest challenge is the biggest he’s ever undertaken: saving the planet.

We could have less than 17 years to live thanks to climate change, Geldof told young people at a conference in Johannesburg, South Africa last week.

Geldof, 61, best known for his Live Aid concert series, believes there will be ‘a mass extinction event’ and has admitted that his generation has let down today’s youth.

Speaking to delegates from 189 countries the singer and activist said, 'we may not get to 2030.’

‘The next war will not be a World War One or a World War Two - it will be the end,’ he warned.

‘The world can decide in a fit of madness to kill itself. Sometimes progress may not be possible. We're in a very fraught time,’ he added.

Sensing how his speech was going over Geldof reportedly concluded by telling delegates at the summit that he was sorry for being ‘bloody miserable,’ adding that his advice would be to ‘just get on with it.’

In recent weeks scientists have warned that the Earth is set for more extraordinary heat waves, floods, droughts and rising sea levels that could swamp coasts and islands as greenhouse gases build up in the atmosphere.

According to the Daily Mail the Intergovernmental Panel on Climate Change stated in its first report for six years that global warming is ‘unequivocal.’ It is 95 percent certain that human activity is the dominant cause, the report added.