Updated Sept. 3, 2016 12:34 p.m. ET
HANGZHOU, China—U.S. President Barack Obama and Chinese President Xi Jinping on Saturday outlined new plans for expanding their joint efforts on climate change, showcasing one of the few areas of agreement in an otherwise tense relationship between the two leaders.
U.S. officials detailed the agreement reached by Messrs. Obama and Xi ahead of what is likely to be their final meeting before a new president enters the White House in January.
The new steps include formal adoption by both the U.S. and China of the international climate-change agreement reached in Paris in December 2015, as well as a road map for achieving emissions reductions in commercial aircraft and for phasing out hydrofluorocarbons, or HFCs, a potent group of gases that are linked to climate change but aren’t covered by the Paris agreement.
The moves cap three years of efforts by Messrs. Obama and Xi to advance climate-change initiatives, following their first meeting as presidents in 2013.
The White House has touted the climate cooperation as a vital form of leadership the two biggest economies have sought to demonstrate for the rest of the world, where developed and developing countries often are at odds. The administration has given a high priority to climate collaboration with Beijing at a time when the two countries have struggled to see eye-to-eye on other economic issues, such as trade, investment rules and exchange rates. The countries have also faced tensions over military affairs and cybersecurity.
Brian Deese, a senior White House adviser, said that the U.S. and China have come “full circle” on climate change with the Paris agreement announcement.
The durability of the U.S. commitments largely hinge on November’s presidential election. Democratic candidate Hillary Clinton and Republican candidate Donald Trumphave taken opposite positions on climate change.
Mrs. Clinton has said she would continue Mr. Obama’s climate-change agenda. Mr. Trump has promised to roll back Mr. Obama’s climate-change measures, questioning the scientific findings behind them.
The formal adoption of the climate-change agreement by the U.S. and China is designed to encourage other nations to formally adopt the Paris pact, helping it enter into force as early as this year, Mr. Deese said, noting that, together, the two countries represent roughly 38% of the world’s emissions.
U.S. negotiators pressed hard last year to structure the Paris agreement in such a way that the countries’ individual targets for greenhouse-gas emissions after 2020 wouldn’t be binding. Any agreement with legally binding targets and the threat of international sanctions would have required the approval of the Republican-controlled Congress, officials said.
Despite criticism from the European Union and other countries that wanted binding targets, the final Paris deal adopted a looser mechanism that requires countries to issue targets and disclose their progress along the way, with the aim of using peer pressure and world-wide attention to win compliance.
Senate Majority Leader Mitch McConnell, a Republican from the coal-producing state of Kentucky, and other GOP lawmakers have attacked Mr. Obama for pursuing the Paris deal without consulting Congress. Democratic lawmakers largely back the deal.
“With respect to the legal form of the agreement, the United States has a long and well-established process for approving executive agreements, that is, a legal form which is distinct from treaties, which are approved through the advice and consent process in the Senate,” Mr. Deese said.
The U.S. and China also expressed support for a prospective deal this year on limited international aircraft emissions through the International Civil Aviation Organization, a branch of the United Nations which is drafting a global standard for airline carbon emissions.
Emissions from aircraft represent about 2% of total global carbon emissions, and the U.S. is the largest contributor to global aviation greenhouse gases, according to federal data.
The two countries agreed as well to support negotiations this year to freeze and phase down the consumption and production of hydrofluorocarbons, powerful greenhouse gases used as refrigerants in place of chlorofluorocarbons, which were blamed for their major role in depleting the ozone layer. The HFC deal would be an amendment to a pact known as the Montreal Protocol, which entered into force in 1989.
Environmental advocates hailed the U.S.-Chinese agreement, saying a once unimaginable area of cooperation had become the brightest spot in the relationship between the two countries.
“When the two largest emitters lock arms to solve climate change, that is when you know we are on the right track,” said David Waskow, international climate director for the World Resources Institute, an environmental think tank in Washington. ”Never before have these two countries worked so closely together to address a global challenge.”
Meanwhile, there was some tension upon the Americans’ arrival here on Saturday, as Chinese officials placed some restrictions on the press corps traveling with Mr. Obama.
Tags: China, climate change, cybersecurity, environment, environmental, European Union, G-20 summit, G20 summit, global carbon emissions, Hangzhou, HFCs, hydrofluorocarbons, Implementing Paris Climate-Change Pact, Obama, U. S., Xi Jinping