Even with new proposals by China and the United States, a deadlock on talks over climate change could not be broken, despite the best efforts of world leaders. President Barack Obama presence did little to inject any momentum into the stalled talks.

With a December deadline fast approaching, the leaders of the world two top polluters, the US and China had hoped their new proposals would engender some form of progress. Addressing the special UN climate change summit, President Hu of China, laid out a plan to control China’s emissions, linking economic growth to efforts to cut these emissions.

Obama, however, offered no new proposals, and has not encouraged the US Senate to pass a climate change bill, something which many diplomats see as crucial to achieving international consensus.

“It is really more of a step back than a step forward,” said Thomas Henningsen, climate coordinator for Greenpeace International, citing the lack of specifics in Obama’s speech.

Hu said China’s new plan was based around aggressively developing renewable and nuclear energy and indicated that emissions would grow slower than economic growth in the future. Nuclear energy, although providing a much greater risk to the environment if there was an accident, is the cheapest and least polluting of all forms of effective power generation.

“We will endeavor to cut carbon dioxide emissions per unit of GDP by a notable margin by 2020 from the 2005 level,” Hu said, according to a transcript of his speech.

Obama said the United States has done more during the first eight months of his presidency than at any point history. George Bush, Obama’s predecessor is well known for opposing climate change treaties, especially as they place more of the burden on developed economies while allowing developing nations to increase emissions unchecked.

“Our generation’s response to this challenge will be judged by history, for if we fail to meet it — boldly, swiftly, and together — we risk consigning future generations to an irreversible catastrophe,” Obama said.

“The time we have to reverse this tide is running out.”