Japan has announced plans for a major cut in greenhouse gas emissions. Here are the promises that other countries and supra-national bodies have already made.
Japan's next Prime Minister Yukio Hatoyama - who will be sworn in later this month - has pledged to aim to cut emissions by 25% by 2020 compared with 1990 levels.
His predecessor, Taro Aso, had previously set a target for cutting emissions by just 8% by 2020.
The G8 leaders said at their summit in L'Aquila in July that rich nations should cut emissions by 80% by 2050, while the world overall should reduce them 50% by 2050.
They said they had agreed to try to limit global warming to just 2C (3.6F) above pre-industrial levels.
The EU has promised a 20% cut in emissions of greenhouse gases by 2020, compared with 1990 levels. It has said that the target will be increased to 30% if there is a satisfactory international agreement.
It also says 20% of the bloc's total energy mix should come from renewables by 2020, and there should be a 20% improvement in energy efficiency by the same year.
President Barack Obama is backing a bill intended to cut emissions by about 17% by 2020 compared to 2005 levels, and by 83% by 2050. The House of Representatives has passed the bill but the Senate has yet to decide.
The Australian government says it will cut emissions by 5 - 25% by 2020 compared to 2000 levels depending on what other countries agree, and by 60% by 2050. It is also planning to introduce an emissions trading scheme but it faces opposition in the Australian Senate.
China has set domestic targets for energy efficiency and use of renewable energy but nothing specifically on emissions. It may introduce an "emission intensity" target, ie the level of emissions for each unit of economic output. But that has not happened yet.
India has not set targets to cut emissions.
Brazil has not set targets to cut emissions.
It is probable that any new deal negotiated at the UN climate conference in December will place obligations on major developing economies such as China, India and Brazil. These will probably take the form of limits on the future growth of emissions and, in the longer term, cuts in emissions.