The final climate change report by the Intergovernmental Panel on Climate Change has found it is now or never if the world is to stave off climate disaster.
The IPCC report says even if all the policies to cut carbon currently in place were fully implemented, the world will still warm by 3.2C this century.
It says greenhouse gas emissions must peak by 2025 and then be halved this decade or the world will be hit by "unprecedented heatwaves, terrifying storms, and widespread water shortages."
Professor Simon Lewis of University College London, says the report will hold countries accountable for their inaction.
Massey University Emeritus Professor Ralph Sims was a review editor on the report. He spoke to Susie Ferguson.
