From the BBC:

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.