More difficulties may arise in the second week of the Cancun climate change negotiations, Martin Khor, executive director of South Center, warned on Saturday.

The difficulties are created when some developed countries explicitly announced they would not continue to commit themselves to cut greenhouse gas emissions for the second period under the Kyoto Protocol, when the first period expires in 2012, Khor said in an exclusive interview with China Daily.

He said without a second period commitment from the developed countries, the Kyoto Protocol- the only legally-binding system that regulates emission cuts- could be dismantled.

Any alternative, such as voluntary commitment, will not rally enough actions to tackle climate change, he said.

He cited the latest study done by United Nations Environment Program, which shows the voluntary commitment approach by the developed countries under the Copenhagen Accord, including the United States, was not enough to reduce GHG emissions.

They "would only reduce GHG emissions by 16 percent, instead of 40 percent that is required," he said.

"In the worst scenario, this 16 percent comes with conditions. If you don't meet the conditions, then in worst scenario, the developed nations will increase emissions by 6 percent; they will not decrease emissions," He said.