The APEC summit ended in the Chinese capital with an unusual joint press conference with Obama and Xi Jinping. The two countries, which account for 45 per cent of the world's pollution, agree to reduce greenhouse gas emissions, but set deadlines to the next decade. Meanwhile, Chinese authorities censor air quality data.

Beijing (AsiaNews) - China and the United States are set to limit "greenhouse gas emissions" following an "historic agreement" that shows how the two great countries can "lead the global effort against climate change," said President Barack Obama.

The US leader hailed the Sino-US deal at an unusual joint press conference with his counterpart Xi Jinping, following an agreement finalised on the sidelines of the Asia-Pacific Economic Cooperation (APEC).

In essence, the two governments acknowledge the need for action to protect the environment and limit the damage already done. However, several obstacles remain.

In the United States, the Republican Party, which just won the midterm elections and will soon be in control of both the US Senate and House, is opposed to the deal.

The GOP (Grand Old Party), which represents business interests, has already called it "unrealistic," a danger to the economy that would bolster "job-destroying red tape".

Secondly, several analysts note that few details about the agreement are known. Its content have not been made public, except in general terms, and it is unclear whether any sanctions would be put in place for failure to meet deadlines.

Targets also remain elastic. Under the deal, Washington is committed to reducing greenhouse gas emissions by about a quarter cent by 2025, over 2005 levels. China set a target for its emissions to peak by 2030 before cutting. In both cases, neither Obama nor Xi will be in office.

What is more, a question mark hangs over China's commitment. On the day of the "historic agreement", for example, the government censored air quality data for Beijing.

Some air quality applications for mobile phones and computers failed to provide data for the capital this week. Instead, a message said the government had ordered its censorship.  "We hope you can understand," the app's developer told a news agency.

During the press conference, the two leaders also answered some questions about China's human rights situation and Hong Kong.

Xi Jinping refused to answer questions about why some New York Times journalists were denied a visa, except to say, "When a car breaks down on the road, perhaps we need to get off the car to see where the problem lies."

For his part, President Obama "reiterated to President Xi" America's "unwavering support for fundamental human rights".

With respect to critical attitudes by the press and pro-mainland politicians in Hong Kong vis-à-vis the United States, the American president said that he "was unequivocal in saying to President Xi that the United States had no involvement in fostering the protests that took place there".

On the issue of freedom, Xi gave the standard reply Chinese leaders offer, namely that "China has made enormous progress in its human rights".

He failed however to answer a question about Nobel Peace Prize laureate Liu Xiaobo who is in prison serving an 11-year sentence.

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