The US and China have resumed formal climate talks for the first time since they were put on ice earlier this year when the relationship became strained over Taiwan.
US President Joe Biden and China President Xi Jinping agreed to address climate change in their recent exchange in Bali, while top Chinese climate negotiator Xie Zhenhua and John Kerry, the US special presidential envoy for climate, did the same at COP27 in Egypt.
"Discussions between China and the US … [were] very candid, friendly, active and positive, and very constructive," Mr Xie said, according to Chinese state broadcaster CCTV.
The US secretary of state will also visit China next year to continue this conversation.
But at time when the urgency around the climate crisis is only increasing, people around the world are calling for less talk and more action.
So, what could two of the world's biggest carbon emitters be discussing when it comes to collaborating on climate change? Will any concrete actions be revealed as relations thaw?
'It is uncertain what the future will hold'
Dr Lucie Qian Xia, a China policy fellow at the Grantham Research Institute, was at the COP27 climate summit at Sharm El-Sheikh, Egypt.
She welcomed the meeting between the presidents, and said it was an encouraging moment.
"The summit sends an important signal to the world that two of the world's largest economies are willing to break the ice in terms of tackling climate change and other global challenges," she said.
But when it came to the finer points of the collaboration between the US and China, Zoe Wang, a climate issues expert at James Cook University, said the conversation was mostly symbolic.
"While China and US had re-opened climate talks, it is uncertain what the future will hold. At this moment, no details are revealed."
However, Dr Wang said that a lack of concrete climate cooperation at the national level does not mean no action at all.
The two countries have promoted climate cooperation at a lower state level despite deteriorating bilateral relations over the past years.
"Especially on the issue of low-carbon technology and emissions trading scheme, as the governor of California just renewed its MOU with China on climate cooperation," Dr Wang said.
In April, the US state of California and China’s Ministry of Ecology and Environment signed an agreement on collaboration and strategies to achieve carbon neutrality, promote nature-based solutions, and advance climate-resilient infrastructure.
Will China contribute to the 'loss and damage fund'?
A key sticking point between the US and China relates to the way China is designated as a "developing" country, rather than a "developed" country, meaning it won't have to contribute to the new "loss and damage" fund drafted at the COP27 summit.
The loss and damage fund is intended to help developing countries bear the immediate costs of climate-fuelled events such as storms and floods.
As part of the draft that was agreed to in the dying hours of the summit, major emerging economies such as China would not initially be required to contribute to the fund.
But that option remains on the table and will be negotiated over the coming years.
This was a key demand of the European Union and the United States, who argued that China and other large polluters currently classified as developing countries have the financial clout and responsibility to pay their way.
China aims to be carbon neutral 'before' 2060
Mr Xi said at the Chinese Communist Party's 20th National Congress in mid-October that climate change was one of Beijing's priorities.
China's decarbonisation goal, known as "30-60", outlines a vision where carbon dioxide emissions peak by 2030, while carbon neutrality is achieved by 2060.
In a speech at the Egypt summit, China's climate envoy Mr Xie implied China would accelerate its decarbonisation process, saying carbon neutrality would be achieved before 2060.
While Mr Xie was addressing the crowd, Chinese entrepreneurs were introducing green architectural and communication technologies and sharing their experiences of reducing carbon footprints at a side event of the summit.
Associate Professor Tang Kai, an expert on China's carbon and energy policy at Guangdong University of Foreign Studies, said China had realised the old development model is no longer sustainable and that the green industry and technology was crucial to economic development.
"It's not a matter of whether China wants to do it. Rather, it has to do so to survive in the competition."
Others are less certain about Beijing's plans.
China built more than half of the world's new coal power plants in 2021, and more are being constructed.
"I think John Kerry is completely deluded if he thinks that talking to China will get it to decarbonise," Rupert Darwall, a climate policy analyst, told the ABC's Between the Lines program.
"China is a coal-based economy. Furthermore, the Chinese Communist Party has the ambition to be the world's top power [by 2049]," he said.
"You can't trust them to do anything which is going to be against their strategic and economic interests."
Could Taiwan derail climate talks once again?
Dr Tang said China had cherry-picked climate change as an ice-breaking topic for dialogue with the US.
"There are many difficult issues between China and the United States, compared with the trade war and Taiwan issue, climate change is the least sensitive and easiest area for cooperation," he said.
Taiwan still dominates much of US-China relations.
China repeatedly emphasises that reunification with self-governed Taiwan is a core strategic interest.
It suspended formal climate talks with the United States after US House Speaker Nancy Pelosi's controversial visit to the island in August.
US House Minority Leader Kevin McCarthy, who is set to become the next speaker, has already publicly declared he will visit Taiwan after taking office.
"Climate talk, very much like other bilateral issues between China and the US, is likely to be affected by the controversy over the Taiwan Strait," Dr Wang said.
"China may again use it as an excuse to stop climate dialogue in the future."
