Former Irish President Mary Robinson has warned world leaders they have ‘two decades at most’ to save the planet from climate ruin.

The human rights campaigner and environmentalist was reacting to a report from the UN Intergovernmental Panel on Climate Change.

Robinson has argued for a robust climate agreement by 2015 and agreement by the world to think again about renewables and for a reduction in global economic growth.

The brains behind the Climate Justice foundation, Robinson said, “Let us show that we are ahead of the game on this."

The Irish Times website reports on Robinson’s view that 'business as usual' will not do any more and said that the three UN reports this year had shown that the climate change debate was over.

She added, “Those who are most impacted by climate change are those who had least caused it, vulnerable people living in marginal conditions in the poorest countries in the world.

“I have seen their experiences at first hand through our foundation’s work.