The UN's former top climate official Yvo de Boer has claimed that countries are trying to rewrite the Bali Action Plan.
He says this confuses negotiations between more than 190 nations that have started this week in Cancun, Mexico.
The meeting began last week amid low expectations
The number of heads of state expecting to attend the climate meeting is just 20, compared to the 120 who turned up at the Copenhagen summit.
This year's conference opened on Monday 29 November with marked divisions between industrialised and developing countries.
In an exclusive interview to BBC News, Mr de Boer - who has taken up the role of climate adviser at KPMG consulting - said the agreement reached after a tough two weeks of negotiations in Bali, 2007 should be implemented "loyally" or abandoned for "something new".
"The Bali Action Plan was very clear of what [was] expected of developing countries which is real, measurable and verifiable action in exchange to real, measurable and verifiable support", said the Dutch former diplomat.
Yvo de Boer said he understands China and India's criticism, among other developing nations, about the developed world's supposed lack of ambition for CO2 emissions targets and talks of agreements other than legally binding.
'All the impacts'
On the other hand, the former UN climate chief stressed that, after Copenhagen, countries responsible for more than 80% of the planet's emissions committed to curbing emission measures by 2020, including all of the industrialised countries and over 40 developing countries.
"We have a pretty much global movement forward and I think we need to give it real implementation meaning (in Cancun)," he said.
The former executive-secretary for the UN Framework Convention on Climate Change (UNFCCC) also expressed worries about the lack of influence of "a hundred or so smaller developing countries who have contributed nothing to climate change but will be confronted with all of the impacts".
The fact that climate science has come under fierce criticism is also a cause for concern.
Mr De Boer recalled a meeting with an Indian Environment minister who made it very clear that without a clear link between climate change and everyday problems, such as hunger, it is very difficult for any politician to back climate action.
"We have to rebuild confidence in the science. Show that the IPCC is taking criticism seriously, putting its house in order, putting in place solid checks and balances that will re-establish the credibility of the science."
"I think people tend to think that it's not the fundamentals of climate change that are being called into question but some of the symptoms."
Deal or no deal?
Despite these problems, Mr De Boer said it would be "irresponsible" of governments not to reach some agreement in Cancun.
The world's second biggest polluter, the US, which has recently been surpassed by China, failed to approve its climate legislation in the US Senate last summer.
Mr de Boer argued that during the Kyoto conference, in 1997, when the current treaty to curb global emissions was agreed, no country had legislation in place.
"The fact that the US do not have climate legislation in place now does not need to impede an agreement in Cancun and subsequently in South Africa," said Mr De Boer.
In Cancun, for the first time, Mr De Boer will participate in a UN climate change conference representing the business community and says he is looking forward to it.
"I feel very good about not having the weight of the process on my shoulders and being involved this time more from a business perspective which is all about getting practical things done, getting real results."