By Elise Scott
A push by vulnerable nations to limit global warming to 1.5degC has been dealt a blow with key scientific research blocked at major climate talks in Paris.
Tensions between developing nations escalated on Thursday (local time) when Saudi Arabia played a key role in blocking the conclusions of a two-year review into the adequacy of the agreed two-degree goal.
Vulnerable countries, including the Pacific Islands, are pushing for a more ambitious target, concerned the damage at two degrees would be too severe.
The block means crucial research won't be submitted to the United Nations climate change summit and can't be used as evidence to back the call for 1.5degC.
Pascal Girot, a member of the Costa Rica delegation, says the review is a critical link between science and policy and believes the negotiating process has politicised the science.
"Now we don't have the scientific arguments to push forward an ambitious agreement," he told AAP in Paris.
"It doesn't bode well for substantiating the need for more investment in adaptation or even worse, for loss and damage.
"Because some will ask 'where's the evidence?' and now the science has been blocked out of the negotiations."
Climate financing is a key issue at the Paris talks, with poorer nations demanding the rich hand over funding for adaptation and mitigation.
Pacific Island nations are digging in their heels over loss and damage, which could also be seen as compensation and is a "red line" for developed countries like the United States.
The Philippines, as chair of the collection of vulnerable nations known as the CVF, was furious the negotiations on the two-year review had "taken a bad turn".
"The parties who stand in the way of recommending a sound decisions based on the information available will be remembered by the children of today for the failure in Paris, the delegation said at the concluding session of the review.
"And we will shout it from the roof tops."
The United Nations Framework Convention for Climate Change also highlights the review's importance on its website, saying the 1.5 degree goal would be discussed in Paris "based on the outcome of the review".
The block came as France and Germany became the first developed countries to back the call to strengthen to target from two degrees.
Their declaration boosted the number of nations backing the goal to 108.
Australia and New Zealand aren't publicly supporting the 1.5 goal, however it's understood the Australian negotiators aren't opposed to having some reference to the aim in the final agreement.
Environment Minister Greg Hunt says Australia is playing a brokering role on that issue.
Pacific Island nations, including Kiribati, have urged Australia and New Zealand to back a stronger stance but both nations refused to sign a communique to that effect at this year's Pacific Islands Forum in Papua New Guinea.
Monica Araya, a member of the CVF expert group, said the tensions in Paris went much deeper than just the major players like the United States, China and India.
"These [vulnerable] countries are coming with ideas being blocked by other developing countries, she told AAP in Paris.
"What is becoming very uncomfortable for Paris, is how are you going to deal with the puzzle in the south."
The collection of countries also want 100 percent renewables and decarbonisation by 2050.
Ms Araya believes there's room to negotiate with China - because of its concerns about air pollution - and India - because of the opportunities in solar energy - but Saudi Arabia is another story.