There are few means of ensuring that countries that sign international agreements actually comply; bilateral pacts could fix that.
The Copenhagen global climate change summit began Monday with new urgency for a deal, and eyes on China and the US.
Just before Copenhagen climate talks open, major greenhouse-gas emitter India said Thursday it would aim to slow the growth of its carbon dioxide emissions over the next decade.
China, the largest greenhouse-gas emitter, will not take on emissions caps but has announced its first numerical target. The US and EU are likely to push for more at Copenhagen climate summit.
The Copenhagen summit on climate change is looking less likely to produce a binding CO2 emissions reduction agreement as a new study finds that global carbon dioxide emissions increased 29 percent in the past nine years.
President Obama and other APEC leaders agreed there wasn't enough time to reach an agreement on climate change at the Copenhagen summit next month.
Obama, in first stop of his Asia trip, addressed the thorny issue of a US military base in Okinawa. Despite recent tensions, Obamamania is still strong in Japan.
UN climate change talks in Barcelona have stalled as African countries say the world's rich nations must do more to cut emissions.
India and China's climate-change pact, signed Wednesday, will boost developing nations' bargaining power at the critical Copenhagen talks in December.
With little agreement at the Bangkok UN climate meeting of 180 nations, the agenda for the crucial December Copenhagen conference is still up for heated debate.