US President Barack Obama said at the G8 summit today there is still time to close the gap with developing powers on climate change, after the UN chief criticised the G8 for not going hard enough.
On the first day of the meeting in L'Aquila in Italy, the G8 failed to get China and India to accept the goal of halving emissions of greenhouse gases by 2050.
Obama, hoping to make his mark on his first Group of Eight summit by chairing a meeting of rich and emerging powers on the environment, said progress could still be made before talks on a new UN climate change treaty in Copenhagen in December.
White House spokesman Robert Gibbs said Obama told Brazil's President Luiz Inacio Lula da Silva that "there was still time in which they could close the gap on that disagreement in time for that important (meeting)".
Obama was due to chair the 17-member Major Economies Forum (MEF), which was likely to agree to try to limit global warming to 2 degrees Celsius (3.6 Fahrenheit) versus pre-industrial levels but not to agree on the scale of emission cuts.
UN Secretary-General Ban Ki-moon said progress on climate change at the G8 was so far "not enough".
"This is politically and morally (an) imperative and historic responsibility ... for the future of humanity, even for the future of the planet Earth," the U.N. chief said.
Progress was hampered by the absence of Chinese President Hu Jintao, who left L'Aquila to attend to ethnic clashes in China's northwest that have killed 156 people.
Prime Minister Gordon Brown said he hoped the temperature target would be agree by "all the countries around the table today" - the United States, Japan, Germany, France, Britain, Italy, Canada and Russia, plus emerging powers like China, India, Brazil, South Africa, Indonesia and Mexico.
But one G8 source said it was "not realistic" to expect a deal on emissions. India said developing countries first wanted to see rich nation plans to provide financing to help them cope with ever more floods, heatwaves, storms and rising sea levels. They also want to see rich nations make deeper cuts by 2020.
Temperatures have already risen by about 0.7 Celsius since the Industrial Revolution ushered in widespread use of fossil fuels. Italy's prime minister said everyone should share the burden of tackling the problem.
"It would not be productive if European countries, Japan, the United States and Canada accepted cuts that are economically damaging while more than 5 billion people in other countries carried on as before," Prime Minister Silvio Berlusconi said.
The fragile state of the world economy dominated the first day of the G8 summit, with rich nations acknowledging there were still significant risks to financial stability.
Ahead of today's meeting, emerging nations complained that they are suffering heavily from a crisis that was not of their making.
China, India and Brazil have all questioned whether the world should start seeking a new global reserve currency as an alternative to the dollar. They have said they may raise this today after discussing it amongst themselves yesterday.
Indian Foreign Secretary Shivshankar Menon said developing economies in the so-called "G5" had suggested using alternative currencies to settle trade among themselves. The debate is very sensitive in financial markets, which are wary of risks to US asset values, and is unlikely to progress far in L'Aquila.
The G8 and G5 did hope for progress on the stalled Doha trade talks, with agreement possible on concluding them by 2010. Launched in 2001 to help poor countries prosper, the Doha round has stumbled on proposed tariff and subsidy cuts.
The G5 said it was committed to address outstanding problems on Doha which would provide "a major stimulus to the restoration of confidence in world markets". But it urged rich nations to tear down trade barriers and restore credit to poor countries.