The United States and China, the world’s largest greenhouse-gas emitters, have unveiled new climate change targets in what U.S. President Barack Obama called a "historic" agreement.
Obama and Chinese President Xi Jinping announced the targets on November 12, after bilateral talks in Beijing that followed a two-day Asia-Pacific summit.
"As the world's two largest economies, energy consumers, and emitters of greenhouse gases, we have a special responsibility to lead the global effort against climate change," Obama said.
Obama set a goal for the United States to cut carbon-dioxide emissions between 26 and 28 percent by 2025, compared with 2005 levels.
Xi told a joint press conference that China's country’s emissions would peak by about 2030.
He did not set a specific target, but it was the first time China has set a time frame for peak emissions.
The new goal from the United States is more ambitious than a previous plan to cut emissions by 17 percent by 2020 compared with 2005 levels.
Obama said the United States would work with China to "slow, peak, and then reverse the course of China's carbon emissions."
The two countries produce about 45 percent of the world's greenhouse gasses.
The White House described the deal in a tweet as "big news."
In Berlin, UN climate chief Christiana Figueres said the agreement between the United States and China "provides both practical and political momentum" toward securing a global deal on reducing emissions after 2020, to be finalized next year in Paris.
She said it demonstrated "clear leadership" ahead of the upcoming Sustainable Innovation Forum 2014 in Lima, Peru, in December.
UN climate experts warn that the effects of global warming is likely to be "severe, pervasive, and irreversible," leading to problems such as rising seas and more drastic flooding.
The Paris-based International Energy Agency (IEA) also hailed the joint commitment, with IEA chief economist Fatih Birol saying it represents "a giant leap for mankind."
IEA Executive Director Maria van der Hoeven described it as "a huge opportunity to make the difference."
But she added: "It's not only about announcing a deal, it will be about seeing it's going to work. And there of course we'll have to wait and see how this deal will be really effective."
In the United States, Republican leaders criticized Obama's plan, with Senate Republican Leader Mitch McConnell of Kentucky describing the emission cuts as part of Obama's "ideological war on coal" that would lead to "higher utility rates and far fewer jobs."
On other issues, the United States and China agreed to boost trade, investment, and military cooperation to reduce the possibility of military accidents.
Obama said he welcomed a China that is peaceful, prosperous, and stable.
He added that said he was encouraged by Xi's willingness to engage constructively, and that the two countries have an enormous stake in each other's success.
Xi said he held "constructive talks" with Obama and that the two countries had agreed to speed up discussions on a bilateral investment treaty and to deepen military trust.
Differences were also expressed, with Obama saying he had pressed Xi on China's human rights record and cybersecurity threats.
On pro-democracy protests in Hong Kong, Obama said Washington would encourage free and fair elections, while his Chinese counterpart reiterated China's stance that the protests are illegal.
Xi also said Beijing wouldn't permit interference in Hong Kong's affairs.
The U.S. president also said his country would not intervene in territorial disputes in the South China Sea.
However, he expressed hope that the conflicts would be resolved peacefully, insisting it had an interest in freedom of navigation.