Chinese climate change negotiators fear US Republican Party opposition could hamper a deal to limit greenhouse gas emissions, they warned ahead of talks beginning next week in Lima, Peru.

Earlier this month, Chinese leader Xi Jinping and US President Barack Obama unveiled an estimate that Chinese emissions would stop growing around 2030 alongside US targets. Republican politicians immediately came out against the Obama administration’s pledge.

“Because of internal politics in the US the Kyoto protocol was not ratified, so we are worried that we might face the same problem in the 2015 pact,” Xie Zhenhua, vice director of the national planning agency and the chief negotiator on climate change, told reporters on Tuesday. The Lima negotiations will be followed by a round in Paris next year where a global climate agreement could be sealed.