U.S. climate envoy John Kerry said that he sees COP negotiations producing a deal on carbon-trading rules, a move that would be a major win after more than six years of failed efforts.

"I believe it will," he said in an interview with Bloomberg Editor-in-Chief John Micklethwait in Glasgow. "We could finish the rule book," he said, adding that he was "going out on a limb."

Getting an agreement on the rules for trading carbon credits and offsets would mark a turning point for climate diplomacy. It should bring transparency and accounting rigor to the world of offsets and help countries and companies cut emissions. But talks so far have been fraught and a complex set of technical rules still needs to be hashed out.

Kerry played down expectations for a grand new statement on climate ambition to emerge from Glasgow, as negotiators start drafting the text that will bring the summit to a close this week.

"If I want to deal with the wish list, sure, I want to see something extra," he said at a Bloomberg Green event. "But we have to deal with reality."

At the same time, Kerry said that he was working with Russia and China to get them to participate in a deal to curb damaging methane emissions. "We're working at it," he said, adding that he'd been up to 3 a.m. in talks.

The methane deal is one of the main summit achievements so far — as more than 105 countries have signed up reduce emissions by 30%. Still, it's not binding, and it's a collective goal rather than an individual one. Kerry also pushed back on criticism of China, saying the country's plans show "they will do a lot."

As for the U.S., Kerry touted the Biden administration's goal of decarbonizing the power sector by 2035, and said the U.S. won't have coal plants by 2030.

Climate Talks in Times of Crisis: A Roadmap to COP26

With negotiators getting down to detailed haggling in Glasgow, a theme that's emerging is how to press countries to keep improving on their climate plans, and to make sure progress is made in the next crucial decade. Some countries have yet to update their plans since 2016.

Kerry said that it would be "insanity" not to measure the progress of plans every year, and he'd like that to be reflected in the final text from the summit, which is scheduled to end on Nov. 12.

"We have to have a measurement of ambition," he said. "This is a long journey and now really is the test of whether we can get there."

–With assistance from Akshat Rathi.

Jennifer A. Dlouhy reports for Bloomberg.

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