Climate negotiators are desperately trying to break through the familiar deadlocks and come up with some form of agreement to satisfy the 200 nations attending the Cancun summit.
The ABC reports that no-one expects a legally binding agreement to emerge from the United Nations talks, but without some progress it will be difficult to convince the international community the summits are working.
Australian Climate Change Minister Greg Combet indicated as much when he spoke at the conference, saying the very credibility of the climate talks is at risk.
A climate summit in Denmark in 2009, produced the Copenhagen Accord, under which, the United States, China and another 83 countries made voluntary pledges to reduce emissions or at least to limit their growth.
Now countries want to cement those pledges in Cancun, but the familiar fault lines between rich and poor nations have re-emerged and the roadblocks remain.
Mr Combet says there is a growing sense that the very future of the UN process could take a hit if some kind of agreement does not come out of these talks.
"Too often we allow ourselves to be distracted by process issues and negotiating tactics. It is time now to refocus on the major task at hand," he said.
"It is imperative for the credibility of this process that we are able to make progress here at this conference.
"Australia will continue to make every effort to support a successful outcome," he said.
But the ABC reports there are murmurings that intransigence from Japan, China, the US or Bolivia could scuttle hope of even moderately small deals being done.
Almost 15,000 people are attending the conference. They have been told the meeting has to end by Friday evening in Mexico.