(G20 Summit)Spotlight: China-U.S. leadership in climate action lauded, hopes raised for more

The determination and joint leadership that China and the United States have demonstrated on the sidelines of the Group of 20 (G20) major economies summit in Hangzhou, east China, in fighting climate change wins widespread applause.

In the eyes of some observers, hopes are raised for their continued joint efforts on other issues.

United Nations Secretary-General Ban Ki-moon described their handover on Saturday of legal documents ratifying the UN Framework Convention on Climate Change as making a "historic step."

He also on Sunday commented it as a major success from the Hangzhou summit on Sept. 4-5 by "encouraging the speedy entry into force of this key agreement" signed in Paris last December, while praising the "outstanding leadership" by China and the United States.

French President Francois Hollande on his Facebook account hailed the joint move, while UN climate chief Patricia Espinosa said in a statement that it opens up a venue for the world's sustainable development.

As the world's two largest economies, China and the United States together account for 39 percent of global emissions, while the Paris pact has a 55-percent threshold for it to take effect.

"Nearly two years ago, the early announcement of emissions reductions targets by China and the United States helped catalyze broad support for the landmark Paris climate agreement," said Nathaniel Keohane, vice-president for global climate at the U.S. Environmental Defense Fund, adding that their latest move "will play a similar role."

"Continued global momentum on climate action depends on strong leadership" by them, Keohane told Xinhua.

The joint announcement on climate action by Chinese President Xi Jinping and his U.S. counterpart Barack Obama "represents important progress -- but also highlights where continued leadership will be critical," Keohane added, citing their pledged support for a global market-based measure to ensure carbon-neutral growth in international aviation from 2020 on.

"Civil aviation is one of the world's fastest-growing sources of carbon pollution," Keohane noted, saying China's indication that it expects to participate in 2021 is "a good start."

As the UN aviation agency, the International civil Aviation Organization (ICAO), will meet late September, "concerted climate diplomacy by the U.S. and China will be vital to secure broad participation from their key aviation partners," which "will be crucial to ensuring environmental integrity and avoiding market-distorting loopholes," Keohane pointed out.

From their cemented partnership against climate change, a policy watcher from Mexico also sees hope for China and the United States to work together to tackle other global challenges.

The over-three-hour-long meeting on Saturday between President Xi and President Obama is highly significant since it shows their willingness to join efforts on settling global problems, Liljana Arsovska, an expert on China at the College of Mexico, believes.

In her eyes, the length of their meeting on the sidelines of the G20 summit in Hangzhou also says a lot about this as well as the two leaders' respect for each other.

During the latest meeting between the two leaders, they held in-depth, frank and constructive talks and reached consensus on a series of issues, ranging from bilateral relations, economic restructuring, and global economic and financial governance to regional and international problems of common concern.

"All their meetings have led to results, even if they have not been substantive. The messages they send to the world show that they want to resolve problems," she noted. Endi