There’s still room for progress on climate talks with China despite its suspension of global warming discussions with the US, John Kerry said on Tuesday.

Kerry, the US special presidential envoy for climate, stressed that Beijing could resume those negotiations, which were put on ice in the wake of House Speaker Nancy Pelosi’s visit to Taiwan.

“They suspended — they didn’t terminate,” Kerry said at a New York Times climate event, adding that it was a conscious word choice. “I really hope China will decide sometime in the next days it is worth coming back to this because we owe it to humankind.”

Kerry spoke optimistically last year about the opportunity for the world’s two largest economies to find common ground and make progress on climate change — despite tensions over human rights, intellectual property and other issues. And he has been able to leverage a close relationship with his counterpart in China, Xie Zhenhua, to forge consensus, resulting in a joint agreement to advance clean energy, combat deforestation and tackle methane emissions at the UN climate summit in Glasgow last year.

Now, Kerry’s entreaties to Xie are going unanswered. But it isn’t stopping him from trying.

“I have emailed,” Kerry said. “He’s not allowed to answer me, and it’s very complicated.”

“And he hasn’t,” he quickly added.