Closer cooperation between China and the United States, the top two greenhouse gas emitters, on combating global warming is boosting prospects for a U.N. deal meant to be agreed next year, the U.N.'s climate chief said on Wednesday.
Christiana Figueres also said a "global transformation" of the economy was needed to fight climate change and that time was short if nations were serious about the end-2015 deadline. Little progress has been made so far in negotiations since 2012.
Last month, China and the United States said that they would work together to share information and policies to plan for the 2015 deal. Together they account for about 40 percent of world greenhouse gas emissions.
"I am very hopeful about the U.S.-China conversation and confident that both will be leaders in the agreement," Figueres, head of the Bonn-based U.N. Climate Change Secretariat, told a news conference in London.
"But we do need 195 countries to have confidence in the benefits" of the deal, which is meant to be agreed next year and become effective from 2020.
Lack of willingness by Beijing and Washington to take aggressive action contributed to the failure of a 2009 summit in Copenhagen, the last attempt to agree a climate accord.
Figueres praised China's efforts to combat climate change, saying it had seven regional carbon markets and "is on the path to a national carbon market", as well as being a world leader in solar power.
"China is not necessarily doing this because it wants to save the world but it is in their own interests," she said.
China has suffered domestic protests against air pollution, caused by wide use of coal, that costs it up to 8 percent of gross domestic product in healthcare and lost farm output.
Almost 200 nations will meet in Bonn next week to work on the 2015 deal, due to be agreed in Paris to cut rising emissions of greenhouse gases that a U.N. panel of scientists blames for causing heatwaves, downpours and rising sea levels.
In a sign of little progress, the board of a fund meant to help poor nations cope with climate change wrangled about travel at talks last month in Bali - they decided delegates can fly business class on trips longer than nine hours.
The Green Climate Fund (GCF), conceived in 2009 as the channel for billions of dollars in aid, had received just $33.8 million by the end of 2013 to help with operational costs.
"I am confident the GCF board knows the clock is ticking against them," Figueres said.
The accord due next year is far more complex than the existing 1997 Kyoto Protocol, which only set emissions cuts for industrialised nations. The 2015 deal is meant to apply to all nations.
"There is an enormous amount left to do," said Yvo de Boer, Figueres' predecessor who was appointed this week as head of the Global Green Growth Institute, based in South Korea and which advises developing nations.
The global financial crisis has distracted from climate change in recent years but de Boer said there were signs that world leaders were getting more engaged.
Last year, the U.N.'s panel of climate scientists raised the probability that global warming was mainly man-made, rather than caused by natural variations, to at least 95 percent from 90 percent in a previous assessment in 2007.