World governments are meeting for a key UN climate summit that will attempt to reach a deal on what should replace the Kyoto Protocol, which ends in 2012.
Talks will centre on whether binding targets are needed to cut emissions.
It is the first such meeting since the IPCC, a panel of leading scientists, concluded that climate change was “very likely” caused by human activity.
The two-week gathering in Bali, Indonesia, will also debate how to help poor nations cope in a warming world.
The annual high-level meeting, organised by the UN Framework Convention on Climate Change (UNFCCC), is under pressure to deliver a global agreement on how to cut rising greenhouse gas emissions.
Rachmat Witoelar, the Indonesian environment minister who was named president of the conference, pledged to do his best to deliver a deal.
“Climate protection must form an integral part of sustainable economic development, and it is critical that we act and we act now,” he said.
UNFCCC Executive Director Yvo de Boer urged the international community to use the summit to take “concrete steps” towards curbing climate change.
“We urgently need to take increased action, given climate change predictions and the corresponding global adaptation needs,” he said in his welcome message to delegates.
“In the context of climate change, projections of economic growth and increases in energy demand over the next 20 years, especially in developing countries, point to the urgent need to green these trends.”
Earlier this year, the Intergovernmental Panel on Climate Change (IPCC) published its Fourth Assessment Report (A4R), in which it projected that the world would warm by 1.8-4.0C (3.2-7.2F) over the next century.
Mr de Boer added that the IPCC’s conclusion that climate change was “very likely” the result of human activity ended any doubt over the need to act.
Climate for consensus?
At the top of the conference’s agenda is the need to reach a consensus on how to curb emissions beyond 2012.
This marks the end of the current phase of the Kyoto Protocol, which commits industrialised nations to cutting carbon dioxide (CO2) emissions by at least 5% from 1990 levels.
Critics of the existing framework say binding targets do not work, and favour technological advances instead.
Recently, the UNFCCC itself announced that greenhouse gas emissions from 40 of the world’s richest nations rose to a near all-time high in 2005.
Meanwhile, US President George Bush – who favours technology over regulation – issued a statement saying that the nation’s emissions had fallen by 1.5% in 2006 from levels in 2005.
Mr Bush used the reduction as an endorsement of his climate policy, saying: “Our guiding principle is clear: we must lead the world to produce fewer greenhouse gas emissions.
“We must do it in a way that does not undermine economic growth or prevent nations from delivering greater prosperity for their people.”
However, the European Union backs the use of binding targets. The 27-nation bloc has already committed itself to cut emissions by 20% by 2020.
A number of observers believe the difference between the two economic powerhouses will result in the Bali conference failing to deliver a policy roadmap for “Kyoto II”.
Softening the blow
The conference is also scheduled to consider how to fund projects that will help developing nations deal with the impact of climate change.
Ahead of the climate conference, another UN agency published a report criticising global efforts to date.
The UN Development Programme’s annual Human Development Report said funding currently amounted to $26m (