In the run up to a key global warming report, those sceptical of mainstream opinion on climate change claim they are “winning” the argument.
They say a slowing of temperature rises in the past 15 years means the threat from climate change is exaggerated.
But a leading member of the UN’s panel on climate change said the views of sceptics were “wishful thinking”.
The pause in warming was a distraction, he said, from the growing scientific certainty about long-term impacts.
Prof Jean Pascal van Ypersele spoke to BBC News ahead of the release of a six-yearly status report into global warming by the UN panel known as the Intergovernmental Panel on Climate Change, or IPCC.
Scientists and government representatives are currently meeting in Stockholm, Sweden, going through the dense, 31-page summary of the state of the physical science behind climate change.
When it is released on Friday, the report is likely to state with even greater certainty than before that the present-day, rapid warming of the planet is man-made.
But climate sceptics have focused their attention on the references to a pause or hiatus in the increase in global temperatures since 1998.
The sceptics believe that this slowdown is the most solid evidence yet that mainstream computer simulations of the Earth’s climate – climate models – are wrong.
These computer simulations are used to study the dynamics of the Earth’s climate and make projections about future temperature change.
“The sceptics now have a feeling of being on the winning side of the debate thanks to the pause,” said Marcel Crok, a Dutch author who accepts the idea that human activities warm the planet, but is sceptical about the scale of the effect.
“You are now starting to see a normalisation of climate science. Suddenly mainstream researchers, who all agree that greenhouse gases play a huge role, start to disagree about the cause of the pause.
“For me this is a relief, it is finally opening up again and this is good.”
The view that the sceptics have positively impacted the IPCC is supported by Prof Arthur Petersen, who is a member of the Dutch government team currently examining the report.
“The sceptics are good for the IPCC and the whole process is really flourishing because of this interaction over the past decades,” he told BBC News.
“Our best climate researchers are typically very close to really solid, sceptical scientists. In this sense scepticism is not necessarily a negative term.”
Others disagree.
Bart Verheggen is an atmospheric scientist and blogger who supports the mainstream view of global warming. He said that sceptics have discouraged an open scientific debate.
“When scientists start to notice that their science is being distorted in public by these people who say they are the champions of the scientific method, that could make mainstream researchers more defensive.
“Scientists probably think twice now about writing things down. They probably think twice about how this could be twisted by contrarians.”
BBC © 2013