“The forum will facilitate policy and research exchange between California’s San Francisco Bay Area and the Greater Bay Area of China.”

Gong said the climate gathering would help Hong Kong understand “how innovation and technology drive competition” and provide lessons to empower universities to advance research and apply practical solutions.

Newsom, who was on a rare visit to the city, lauded Hong Kong’s climate policies in areas such as business disclosures and requirements on protected sites, as he spoke about his own state’s efforts in alleviating ecological devastation.

“You guys inspired us,” he said. “Hong Kong’s a remarkable place. You are demonstrating leadership in many different capacities.”

The governor’s weeklong climate-focused tour will take him next to Beijing and Shanghai, as well as the provinces of Jiangsu and Guangdong, where he is expected to meet “high-level” national and local officials and sign memorandums of understanding (MOU) on related policies.

Earlier, his office said the trip was arranged to “advance climate action, promote economic development and tourism and encourage cultural exchange between countries to actively combat xenophobia”.

His visit had attracted bipartisan fire in the United States, with fellow Democrats warning any move to stay silent on human rights issues would prove damaging to diplomatic engagement with China.

One of the keynote speakers at Monday’s conference, Li Yongsheng, deputy commissioner of the Chinese foreign ministry in the city, welcomed Newsom’s visit, saying China-US relations were showing “positive signs of rebounding” in recent months and emphasised the need for further exchanges.

“For bilateral relations to improve, assisting efforts are required,” Li said.

“California has a long history of exchanges with China … I believe Governor Newsom’s visit to China will be a productive one.”

The climate forum would be a powerful catalyst for dialogue between the two sides, analysts said, as they also pointed out Newsom’s visit seemed a preapproved decision by both governments.

China’s Greater Bay Area, which includes Hong Kong, Macau and nine cities in Guangdong, has a combined population of more than 86 million and a gross domestic product (GDP) of about 13 trillion yuan (US$1.8 trillion) in 2022.

Similarly, the San Francisco Bay Area is made up of the city and eight surrounding counties and includes Silicon Valley.

It led the US in economic growth last year with an estimated GDP of nearly US$1.4 trillion, according to research by the Kenan Institute of Private Enterprise.

Speaking on stage at Monday’s conference hosted by the Institute for Climate and Carbon Neutrality, Newsom steered clear of non-climate topics, focusing on the efforts of his state and Hong Kong in battling environmental changes.

He highlighted the large amount of the city that remained in its natural state, pointing to his plans to conserve 30 per cent of California’s land and coastal waters by 2030.

About 75 per cent of Hong Kong’s land is undeveloped, around 40 per cent of which is designated as country park.

He also praised carbon emission disclosure requirements for listed companies. The Hong Kong stock exchange has proposed to make it mandatory for listed companies to disclose their climate-related financial risks and all Scope 3 climate emissions, which are those attributable to suppliers or customers.

Derek Yuen Mi-Chang, a political affairs commentator, called Newsom’s visit an “encouraging sign” of softening Sino-US relations and Hong Kong’s ability to once again act as a middle-ground.

“The whole thing was approved by both sides,” he said, referring to both Beijing and Washington. “It is a clear sign that Hong Kong is being included.”

He said that limiting the climate forum to the two countries’ tech hubs, rather than operating at the national-level, would also help stave off any internal opposition both sides might have during their rapprochement.

“It’s a brilliant idea,” he said. “It doesn’t stir up emotions on either side, either the people or politicians. Climate is the right excuse, of course, because it is less politically sensitive.”

Lau Siu-kai, a consultant at semi-official Beijing think tank the Chinese Association of Hong Kong and Macau Studies, said it was “unrealistic” to expect Beijing and Washington to improve their relationship any time soon, but such subnational engagements could help improve mutual understanding.

“Given Hong Kong’s historically strong relationship with the West, it can play a helpful role by providing a platform where local officials, think tanks, NGOs and other civilians can meet and cooperate,” said Lau, adding Beijing would support the city to shoulder its role.

Newsom is considered to be a leader on tackling climate change in the United States. His administration has enacted rules to phase out the sale of most gas-powered cars in the state by 2035, and has committed to carbon neutrality by 2045.

In recent years, California has helped maintain US-China dialogue on climate change at a time of heightened bilateral tensions.

In 2019, the California-China Climate Institute was launched by the University of California, Berkley, in partnership with Tsinghua University and led by former governor Jerry Brown. It seeks to promote joint research on solutions to mitigate the environmental crisis.

Additional reporting by Willa Wu