BEIJING/WASHINGTON - United States climate envoy John Kerry’s trip to Beijing from Sunday to Wednesday has thawed a year-long freeze in bilateral climate negotiations – an important first step towards making progress on a pressing global issue, analysts said.

But cooperation between the world’s two largest carbon emitters, according to pundits, remains tethered to the overall health of their relationship, which is fragile, even as it appears to be on the mend with a series of top-level meetings that took place in June.