LONDON (Bloomberg) Japan said Wednesday it declined a request from the presiding officer at the climate talks in Mexico to make its position against adopting a new round of greenhouse gas reductions after 2012 more flexible.

"The Japanese position is still very firm," Kuni Shimada, the nation's lead climate envoy, said at the U.N. global warming talks in Cancun. "The COP president wants to see some flexibility, but it's quite difficult for Japan to have the flexibility because that's the position coming from the top."

The greenhouse gas emissions limits agreed on in Kyoto in 1997 expire in 2012. China, India and Brazil say a second round of commitments from industrial nations is necessary to keep the U.N. talks alive.