It took eight years for some countries to ratify the first commitment period and it is not clear how long it needs to get the green light for the second period.

Whether the surplus emissions allowances, or "hot air," from the first commitment period should be retired is also a controversy at Doha talks.

The G77 and China opposed trading carried-over hot air in the second commitment period. Europe is deeply split on the issue, while some other countries, including Russia, propose to profit from their surplus carbon dioxide allowances.

At the same time, the financial aid promised by developed countries to help the world's most vulnerable countries cope with climate change has not been fully delivered.

"Developing countries need sustained investment to help them make the transition to a low carbon economy and adapt to the impacts of climate change: and the cost will rise, the more we delay action to cut emissions. Countries must agree a specific commitment now to provide 60 billion U.S. dollars over the next three years," said Ruth Davis, Greenpeace Chief Policy Advisor.

Measuring, reporting and verifying (MRV) both emissions and funding contributions for developed and developing countries remains a contentious issue as well, with technical negotiations ongoing.

"The negotiations next week are under heavy pressure and overnight meetings are expected, but it is not clear whether any breakthrough will be achieved," said China's Su.

"The significance of the Doha talks is in making appropriate arrangements on remaining issues before starting a new round of talks. China will continue to play a constructive role in this process," Su added.