POZNAN, Poland — Japan is expected to pursue proactive yet balanced climate diplomacy in 2009 to ensure the involvement of the United States, China and India — responsible for nearly half the world's greenhouse gas emissions — in a new treaty to fight global warming.

Policymakers and analysts believe Barack Obama's inauguration as U.S. president on Jan. 20 will inject vigor into U.N. negotiations for a successor to the Kyoto Protocol. About 190 countries aim to adopt the successor pact at a December 2009 meeting in Copenhagen.

In contrast to George W. Bush, Obama has signaled a turnaround in U.S. climate policy by promising to "engage vigorously" in global talks.