The conference on climate change scheduled for December in Mexico represents a “huge opportunity” for a stronger global agreement, U.N. climate chief Yvo de Boer said on Friday.

“While Copenhagen focused very much on very big political issues, there’s huge a opportunity in Cancun in Mexico to actually put the operational framework in place that at the end of the day will make a difference,” Mr. de Boer, executive secretary of the United Nations Framework Convention on Climate Change (UNFCCC), said on the Indonesian resort island of Bali.

Under a non-binding agreement reached at the UN climate change conference in Copenhagen last year, countries agreed in principle on some of the steps to be taken towards tackling climate change. But the Copenhagen Accord has been criticized for lacking a legal framework and concrete objectives. de Boer, who announced on February 18 that he would resign as the UN top climate official in July, was in Bali for an informal ministerial meeting on climate change, held on the sidelines of a United Nations environmental conference.

When asked if the Mexico meeting could produce a legally binding treaty, de Boer said that term meant different things to different countries.

“I think it’s important that in Mexico we focus on the implementation architecture and then decide what legal character that architecture should be given,” he said.

A United Nations Environment Programme report released this week said countries need to set tougher targets to cut greenhouse gas emissions if the world is to keep the global temperature from rising more than 2 degrees Celsius above pre-industrial levels.

Scientists say that temperatures must not exceed this increase if a climate catastrophe is to be averted.

De Boer said it was very important that developed countries start to act on their pledges of 30 billion dollars in short-term financing to help poor countries deal with the effects of climate change.

“Many countries are already confronted with the impacts of climate change and they need to assess their vulnerability and begin to respond to those impacts,” he said.

Greater transparency in the process would also help improve the trust between the developed world and poorer countries, who should be more included in the negotiations, the Dutch diplomat said.

“Many developing countries feel they are being called upon to do something without it being clear that they will have the resources or the instruments to be able to do that,” he said.

To restore their confidence in the process, a clear framework for how the technological and financial support is to be provided to poorer countries is “critical”, he added.