With the fate of the world's environment hanging in the balance, China has tried to raise the stakes even higher by making demands in exchange for climate cooperation with the United States.
The developing standoff over commitments to limit global warming led to a 90-minute phone call last week between President Joe Biden and President Xi Jinping in an attempt to clear the air.
But the outcome for climate policy remained unsettled as China continued to link broader issues of U.S.-China relations to environmental affairs.
The phone talks between the two leaders followed stormy negotiations between John Kerry, the U.S. special presidential envoy for climate, and Chinese officials, leading to a high-level impasse.
During the second of two recent visits to China, Kerry ran into a virtual stone wall when he met by video link with Foreign Minister Wang Yi on Sept. 1.
Kerry's trip and face-to-face talks with Chinese officials in the northern port city of Tianjin were aimed at promoting cooperation on carbon emissions in the runup to a critical U.N.-sponsored climate conference in Glasgow, Scotland in November.
Despite bilateral tensions, the calls for cooperation stemmed from a realization that international attempts to avert the worst effects of global warming will fall short without greater efforts by the world's two largest sources of carbon dioxide (CO2) emissions.
According to the latest available figures from the Global Carbon Atlas, China's CO2 emissions from fossil fuels accounted for 27.9 percent of the world total in 2019, while U.S. emissions stood at 14.5 percent.
Last September, President Xi pledged that China would reach a peak in its emissions before 2030 and achieve "net- zero" neutrality before 2060.
In April, President Biden set the U.S. target for emissions reductions at 50-52 percent below 2005 levels in 2030 with net-zero neutrality "no later than 2050." Climate advocates hope that both countries will agree to do more.
In the days before Kerry's visit, Chinese officials spoke repeatedly in favor of tension reduction and closer cooperation on a range of issues despite bilateral differences.
"In fact, the need for China-U.S. cooperation is not decreasing, but increasing. Our two countries should not be enemies, but partners," said China's ambassador to the United States, Qin Gang, in a Washington speech on Aug. 31, one day before Kerry's meeting with Wang.
A few days before that, a Ministry of Commerce spokesperson cited the mutual benefits of trade in an online briefing for the bilateral comprehensive economic dialogue.
In the first seven months of the year, China's imports of U.S. goods jumped 50.4 percent from a year earlier, while China's exports to the United States climbed 36.9 percent, said Gao Feng, according to the official English-language China Daily.
"China always emphasizes the two sides should work together to create conditions for the expansion of China-U.S. trade cooperation," Gao said.
The tone of such statements made Wang's confrontational message on climate cooperation something of a surprise.
Climate cooperation
According to a Foreign Ministry statement, Wang warned Kerry that "deteriorating U.S.-China relations could undermine cooperation between the two on climate change," the Associated Press reported.
"Wang told Kerry ... that such cooperation cannot be separated from the broader relationship and called on the U.S. to take steps to improve ties," the AP said.
In the statement posted on the Foreign Ministry website, Wang told Kerry that Washington "should pay attention and actively respond" to the "two lists" and "three bottom lines" that Beijing defined as requirements for improved relations.
The statement implied that climate cooperation would be conditioned on resolving the entire range of U.S.-China disagreements, including decades-old foreign policy differences that have nothing to do with climate change.
"The United States hopes to transform cooperation into an 'oasis' in Sino-U.S. relations, but if the 'oasis' is surrounded by 'deserts,' the 'oasis' will sooner or later be deserted," Wang said.
In July, China gave U.S. Deputy Secretary of State Wendy Sherman the two lists, one of which covered "errors" for Washington to address, while the other raised issues regarded as "important" to China, CNBC reported.
The lists included a demand that Washington should end its attempts to extradite Huawei chief financial officer Meng Wanzhou from Canada to face charges of violating U.S. export rules, as well as visa restrictions on Chinese students and Communist Party members, curbs on Chinese companies and other issues, CNBC and China's Global Times said.
The "three bottom lines" outlined by Wang also included a broad range of policy issues.
First, the United States "must not challenge, slander or even attempt to subvert the path and system of socialism with Chinese characteristics," said the document given to Sherman, the official Xinhua news agency reported.
Second, Washington "must not attempt to obstruct or interrupt China's development process." As part of the demand, China called for the removal of all unilateral U.S. sanctions and bans on technology trade.
Third, Wang insisted that the United States must not "infringe upon China's state sovereignty" or damage its "territorial integrity," referring to U.S. penalties for rights abuses in Tibet, Hong Kong and Xinjiang. China's sovereignty claims also extend to Taiwan and the South China Sea.
Taken together, the demands for sweeping changes in U.S. policies toward China put the prospects for a climate change agreement on thin ice.
After two days of talks with China's special climate envoy Xie Zhenhua, Kerry pushed back against Beijing's attempts to establish linkage between climate agreements and a wish list of grievances over unrelated disputes.
"My response to them was, look, climate is not ideological, not partisan and not a geostrategic weapon," the former secretary of state told reporters, according to Reuters.
Tension increase
Climate policy experts have acknowledged that the high stakes for an agreement on emissions targets may raise tensions on other issues.
"Kerry and Xie have been able to carve out a channel for ongoing communication on climate change, which is extremely valuable right now," Joanna Lewis, a Georgetown University associate professor, told The New York Times.
"Yet it is increasingly difficult to fully insulate climate change from the broader tensions," Lewis said.
But if China sticks to its demands, the effect would essentially hold the climate hostage to an insurmountably long list of policy differences.
China also added to the conditions for cooperation with demands that the United States must stop calling for a World Health Organization investigation into origins of the COVID- 19 pandemic, charging that it was nothing more than a smear campaign against Beijing.
In a phone call with Secretary of State Antony Blinken reported by Xinhua on Aug. 29, Wang called on the United States to "stop undermining China's sovereignty, security and development interests."
In the weeks before the Tianjin meetings, Kerry pressed China long and hard to stop building coal-fired power plants, arguing that the projects will frustrate plans to meet climate goals.
But China pushed back, arguing that its plans to supply its energy needs are also a matter of sovereignty and its own affair.
"China already has its own plans and road map for achieving its climate goals," the South China Morning Post said, quoting "a person familiar with the two countries' negotiations."
"China would not accept Washington telling it what to do and when," the source said.
The outcome of the Biden-Xi phone talks seems to be a softening of tone in the demands from Beijing, which could allow climate talks to go ahead.
"Relevant departments of the two countries, on the basis of respecting each other's core concerns and properly managing differences, may continue their engagement and dialogue, and advance coordination and cooperation on climate change, COVID-19 response and economic recovery as well as on major international and regional issues," a Xinhua commentary said.
But it remained to be seen whether there will be any change in the substance of China's demands or its climate pledges.
The Chinese warnings may still represent red lines, leading to an impasse and failure to reach new agreements in time for the U.N. conference of parties, known as COP26, in November.
An alternate reading is that China's far-reaching conditions for a new climate deal are a measure of the difficulty of meeting more stringent emissions goals.
Either way, the next two months are likely to be a period of intense diplomatic activity and recalculation of the critical interests in U.S.-China ties.
Adding to the uncertainty are questions about whether the COP26 meeting will be held in November at all.
In the past week, a broad coalition of climate groups called for postponing the conference. In a statement, the Climate Action Network voiced concerns that the COVID-19 pandemic and quarantine requirements would raise costs for poorer countries and "makw it impossible for many representatives to attend."
Kerry battled back against postponement, citing the risk that any delay could allow some nations to "backtrack" on their climate commitments, The New York Times reported.
"We don't have time to mess around with reconvening," Kerry said.