NEW DELHI: The world’s top carbon emitters -- the United States and China -- have reached a landmark deal on climate change, with both countries pledging to reduce greenhouse gas emissions by about a third by 2030.

The agreement, which was announced in Beijing, involves the US reducing the level of its emissions -- based off 2005 levels -- by 26 to 28 percent by 2025. This new goal is up from a previous 17 percent reduction by 2020 target. The US’ independent goal is to cut emissions by 80 percent by the year 2050.

China, which has thus far been vague regarding its commitment to reducing emissions, pledged to stop its emissions from rising by 2030. This marks the first time China has committed to reaching such a goal. Chinese President Xi Jinping said that toward meeting this goal, 20 percent of China’s energy requirements will come from alternative sources -- such as solar and wind energy -- by 2030. “We agreed to make sure that international climate change negotiations will reach an agreement in Paris," Xi told reporters after the pledge.

The White House issued a statement that China is embracing the “energy revolution.” The statement added that China has signed onto providing an "additional 800-1,000 gigawatts of nuclear, wind, solar and other zero emission generation capacity by 2030, more than all the coal-fired power plants that exist in China today and close to total current electricity generation capacity in the United States.”

US President Barack Obama referred to the agreement between the two countries -- which comes ahead of efforts to secure a global deal on reducing emissions after 2020 to be finalised next year in Paris -- as “historic,” adding that the US will work with China to "slow, peak and then reverse the course of China's carbon emissions.”

However, whilst the deal has been hailed by the White House, the fact that Congress will be controlled by Republicans -- who have generally criticised efforts to combat climate change -- indicate that roadblocks remain. “This unrealistic plan, that the president would dump on his successor, would ensure higher utility rates and far fewer jobs," Senate Republican Leader Mitch McConnell said in reference to the agreement.

An unnamed official told CNN that despite opposition, Obama will remain committed to combatting climate change. "Congress may try to stop us, but we believe that with control of Congress changing hands we can proceed with the authority we already have,” the official said. "This is really the crusade of a narrow group of people who are politically motivated and have made this a cause celebre, but we believe we will be successful,” the official said.

The announcement on climate change and reducing emissions comes as the US and China signed agreements on trade tariffs, military maneuvers, and easing travel visas. As part of the trade deal, the two countries agreed to get rid of $1 trillion worth of tariffs a year on global sales of information and communications technology, medical equipment, and game consoles. The deal needs to be approved by the World Trade Organisation before it can be implemented.

The two leaders also reportedly discussed the recent protests in Hong Kong, with Obama saying that the US will encourage free and fair elections and Xi reiterating that China’s issues were internal affairs.