UN climate talks on Sunday approved a roadmap for a 2015 pact that for the first time will bring all major carbon emitters into a single legal accord.
The deal was reached after nearly 14 days of bruising talks under the UN Framework Convention on Climate Change.
Under it, 194 nations will seek an accord aimed at beefing up action against greenhouse gases blamed for damaging Earth’s delicate climate system.
Approved by 2015, it would be implemented from 2020.
Current measures to tackle carbon emissions are falling far short of the goal of limiting warming to two degrees Celsius (3.6 degrees Fahrenheit).
According to research presented at the Durban talks, the world is on track for a 3.5 C (6.3 F) rise, spelling worsening droughts, floods, storms and rising sea levels for tens of millions of people.
Key components of the 2015 accord remain to be hammered out, and observers say the task will be arduous.
Thorny issues include the still-undefined legal status of the accord and apportioning cuts on emissions among rich and poor countries.