There is still no absolute yes or no to a second commitment period of the Kyoto Protocol from the European Union side, said Peter Wittoeck, a Belgian envoy who speaks for the EU, during a press conference at the two-week climate summit in Cancun.

"We're willing to consider a second commitment period of the Kyoto Protocol," said Wittoeck, "but if it is only the EU that is under such a commitment without the rest of the world … [then] that would not be a solution for the global climate problem."

"And we also need to improve the environmental integrity of the future mechanisms of the Kyoto Protocol," he said.

The Kyoto Protocol was adopted in 1997 by 16 major emitting countries that committed to cutting emissions by about 5 percent below 1990 figures by 2012. It is the only existing legally-binding mechanism to reduce carbon emissions. The United States remains outside the protocol.

Japan said on the first day of the Cancun summit that it would not sign up to a second commitment period of the protocol, because the current mechanism addresses only 27 percent of global carbon emissions.

Developing countries said that Japan's announcement could be destructive to the negotiations for a new global climate treaty.

Laurence Graff, head of the international relations unit at the European Commission's climate department, said the EU is well on track to reach its emission reduction target for the first commitment period of the Kyoto Protocol.

"Projections show that the EU may even over-reach our target by 2012," Graff said at the conference.

Wittoeck also said the EU is considering scaling up its carbon emission reduction pledges made at last year's Copenhagen climate summit.

"We already have the legislation for reducing carbon emissions by 20 percent from 1990 levels by 2020," he said, "and now we realize that we need to do more … and [we are] considering raising the target to 30 percent."