The deep divide over the U.S. role was evident in the American representatives in attendance. U.S. Energy Secretary Rick Perry arrived for the event after stopping in Tokyo, where he insisted America would not back down from its role as a leader on climate issues. Perry has been an advocate for the fossil fuels industries.

In contrast, California Gov. Jerry Brown, a fierce critic of Trump’s decision, argued that the threat of climate change could be more dangerous than the fascism the world saw during World War II.

Canadian Natural Resources Minister Jim Carr told CNBC he believed states such as California would likely pick up the mantle for clean energy investment and other environmental matters in the U.S. Carr also praised China’s efforts to become a leader in clean energy.

“I’m particularly happy to be here in China and to see just how much investment the Chinese government is devoted to clean technologies and renewable sources of energy,” he said.

Beijing reiterated its commitment to the Paris accord after Washington pulled out last week. China is one the biggest investors in renewable energy solutions. Its policies, however, have had a spotty record. Despite more than a decade of investing in solar and wind, the country still relies heavily on coal and is the world’s largest emitter of greenhouse gases.

Perry has called on China to step in and take a larger role on climate matters. Clean energy supporters such as Amin of IRENA expressed hope Perry will continue to see the benefits of nurturing a clean energy industry back home, including in Texas — Perry’s home state.

“Texas is the biggest wind state in the U.S. and what Texas has been able to achieve with renewables is remarkable and I hope [Perry] brings that leadership to the U.S. in terms of [its] clean energy sector,” Amin said.

Russia, which has struggled to tap its clean energy potential, also believes America’s role in the fight for climate change is still evolving.

“Maybe tomorrow, [the U.S. Energy Secretary] will say another policy — [have] another change in their policy,” Anton Inyutsyn, Russian deputy energy minister, told CNBC.

Inyutsyn also weighed in on the outlook of Russia’s traditional energy source: oil. He dismissed concerns that Russia might not be committed to coordinated production cuts with OPEC nations.

“As you know, we [made] this decision and will try to keep it during one more period,” he said, referring to a recent multi-month renewal of the OPEC agreement. “After that, we will have a meeting and discuss this.”