United Nations Secretary General Ban Ki-moon has opened high-level talks at the climate change conference in Bali with a call to action.
He said that if no action was taken, the world would face impacts such as drought, famine and rising sea levels.
Delegates are hoping to agree a “Bali roadmap” leading to further cuts in greenhouse gas emissions when the Kyoto Protocol targets expire in 2012.
The US and Canada are among countries opposed to further binding targets.
The UN itself wants developed countries to commit to cuts of 25-40% from 1990 levels by 2020.