China will increase efforts to improve energy efficiency and curb the rise in CO2 emissions, President Hu Jintao has told a UN climate summit in New York.

Mr Hu gave no details about the measures, which should mean emissions grow less quickly than the economy.

The US, the world’s other major emitter, said China’s proposals were helpful but figures were needed.

About 100 leaders are attending the talks, ahead of the Copenhagen summit which is due to approve a new treaty.

Today, the United Nations Secretary General, Ban Ki-moon, will chair a meeting on Climate Change. He does so because he hopes that such a gathering of Heads of Government will galvanise the chances of agreement being reached in December in Copenhagen at COP15.

It seems that he is aware, as are many others, that the threat of climate change is very real and that, as scientists now believe we have less than ninety five months left to avert the risk of its catastrophic consequences, we need to act and act very fast.

Of more than 100 world leaders who gathered Tuesday at the United Nations for a summit meeting on climate change, two mattered most: Barack Obama and China’s president, Hu Jintao. Together their countries produce 40 percent of the world’s greenhouse gas emissions. Together they can lead the way to an effective global response to this clear global threat. Or together they can mess things up royally.

In less than three months, negotiations will begin in Copenhagen for a new agreement to replace the 1997 Kyoto Protocol. The hope is these talks will produce commitments from each nation that, collectively, would keep temperatures from rising 2 degrees Celsius (or 3.6 degrees Fahrenheit) above preindustrial levels. That will require deep cuts in emissions — as much as 80 percent among industrialized nations — by midcentury.

A growing rift between the US and Europe is overshadowing Tuesday’s United Nations climate change summit in New York, further damping hopes for a breakthrough at the Copenhagen talks in December.

Connie Hedegaard, the Danish environment minister, lowered expectations, saying: “Things are looking difficult and too slow, that is the fact.”

The downgrading of expectations comes as relations between the US and Europe, which started the year of talks as allies, near breakdown.

The time is now for an international deal on climate change.

In just 11 weeks, the world will convene in Copenhagen, under the auspices of the United Nations, to forge a new international agreement on climate change. It is a historic moment: the ultimate test of global cooperation. Yet the negotiations are proceeding so slowly that a deal is in grave danger.

If we miss this opportunity, there will be no second chance sometime in the future, no later way to undo the catastrophic damage to the environment we will cause. So when world leaders gather this week, first at the United Nations in New York and then at the G20 summit in Pittsburgh, it is essential that we move toward resolving the issues that still divide our nations. As scientists spell out the mounting evidence both of the climate change already occurring and of the threat it poses in the future, we cannot allow the negotiations to run out of time simply for lack of attention. Failure would be unforgivable.

The Senate climate debate has largely been in standby mode since June, but Environment and Public Works Chairwoman Barbara Boxer (D-Calif.) is ready to kick-start the process with the release next week of a draft bill.

Sources off Capitol Hill say they expect Boxer to start legislative hearings during the week of Oct. 5, with a tentative markup penciled in for the week of Oct. 12.

Of course, much depends on the fate of the Senate health care bill, just how quick U.S. EPA can turn around an economic analysis of Boxer’s legislation and whether the chairwoman wants to satisfy key moderates on her panel, which include Sens. Max Baucus (D-Mont.) and Arlen Specter (D-Pa.).