Worried that an upcoming climate summit might fall short of environmentalists’ hopes, President Barack Obama spoke with Chinese President Hu Jintao this week to urge that both nations lead the way to a new treaty reducing emissions that are accelerating global warming.

“Both leaders acknowledged each is taking significant actions to confront climate change and reduce emissions,” the White House said in a statement Wednesday summarizing the Tuesday night talk. “President Obama noted the importance of working toward a successful outcome at the December Copenhagen Conference and the importance of leadership from the United States and China in that regard.   

“To that end, the two Presidents committed to having their teams redouble efforts to work with each other and other countries to achieve success at Copenhagen.”

In broad terms, China acknowledged that there remain stumbling blocks to a broad international agreement that would commit countries to cutting the emissions from smokestacks and tailpipes that trap heat in the atmosphere.

“Although problems remain in talks for a final deal, there are hopes for a positive result at the Copenhagen Conference as long as the convening parties work together closely," Hu said, according to the Xinhua Chinese news agency.

The struggle to control emissions is likely to be high on the agenda during an upcoming trip by Obama to Asia, first at a summit of Asian leaders in Singapore and then in Beijing at a summit with Hu.

It’s also possible that Obama could travel to Copenhagen for the climate change meeting if the UN-sponsored meeting adds a summit for national leaders.