A major climate change conference which will spell out what needs to be done to combat global warming has got under way in the Thai capital Bangkok.
It is the third such summit this year by the Intergovernmental Panel on Climate Change (IPCC).
It aims to be the key guide to climate change technology and economics.
A final draft seen by the BBC will say nations can protect the climate, but only if they make policies to halt the global growth in emissions by 2030.
The draft refers to stabilising emissions between 450 and 550 parts per million of CO2 in the atmosphere.
Anything less is unrealistic, economists believe.
But America and China are alarmed by any discussions of a safe limit because it increases pressure to curb their pollution.
The words of this IPCC report will appear from the mouths of world leaders when they meet face-to-face over climate change at the summit of the group of eight most industrialised nations (G8) in June.