China's refusal to accept requests for deeper carbon emissions cuts during recent visits from the top climate envoys of the United States and Britain may undermine progress at the upcoming global climate summit in Glasgow in November, experts say.

China rebuffed U.S. envoy John Kerry's appeal to strengthen its emissions goals ahead of the COP26 summit by saying climate could not be separated from the wider breakdown in the countries' relationship.

This shift in China's tone on climate relations between the world's two biggest greenhouse gas emitters has sapped momentum for the Glasgow talks and contrasts with the cooperation between the two countries in 2015 that paved the way for the landmark Paris climate agreement.