The following is an edited version of an article by the BBC:

The unrestricted use of fossil fuels should be phased out by 2100 if the world is to avoid dangerous climate change, a UN-backed expert panel says.

The Intergovernmental Panel on Climate Change says in a stark report that most of the world’s electricity can – and must – be produced from low-carbon sources by 2050.

If not, the world faces “severe, pervasive and irreversible” damage.

The UN said inaction would cost “much more” than taking the necessary action.

The report says that reducing emissions is crucial if global warming is to be limited to 2C – a target acknowledged in 2009 as the threshold of dangerous climate change.

The report suggests renewables will have to grow from their current 30% share to 80% of the power sector by 2050.

In the longer term, the report states that fossil fuel power generation without carbon capture and storage (CCS) technology would need to be “phased out almost entirely by 2100”.

“Science has spoken,” UN Secretary-General Ban Ki-moon said. “There is no ambiguity in their message. Leaders must act. Time is not on our side.”

“There is a myth that climate action will cost heavily,” said Mr Ban, “but inaction will cost much more.”