A draft of the next report of the Intergovernmental Panel on Climate Change (IPCC) has been leaked on climate sceptic websites.
The 14-chapter draft report was posted on a US-based blog site called stopgreensuicide and then posted on another site critical of climate science.
The leaker and other climate sceptics have isolated one section of the draft to suggest that cosmic rays such as those of the Sun may have a greater influence on warming than had been claimed.
Professor Steve Sherwood, the director of the Climate Change Research Centre at the University of NSW, was the lead author of the chapter in question.
He says the idea that the chapter he authored confirms a greater role for solar and other cosmic rays in global warming is "ridiculous".
"I'm sure you could go and read those paragraphs yourself and the summary of it and see that we conclude exactly the opposite - that this cosmic ray effect that the paragraph is discussing appears to be negligible," he told PM.
"What it shows is that we looked at this. We look at everything.
"The IPCC has a very comprehensive process where we try to look at all the influences on climate and so we looked at this one."
Professor Sherwood says research has effectively disproved the idea that sunspots are more responsible for global warming than human activity.
"There have been a couple of papers suggesting that solar forcing affects climate through cosmic rays, cloud interactions, but most of the literature on this shows that doesn't actually work," he said.
"Even the sentence doesn't say what they say and certainly if you look at the context, we're really saying the opposite."
Climate communication fellow for the Global Change Institute at the University of Queensland John Cooke says, if anything, warming is worse than predicted in the last IPCC report.
"One of the main differences between the previous IPCC report and this one is [that] they're including the role of ice sheets on sea level rise," he said.
"Ice sheet loss has accelerated, and so they're contributing more and more to sea level rise.
"Back in the fourth assessment report in 2007, I think [the predicted sea level rise] was around 20 centimetres [by the end of the century]. Now it's getting up towards one metre."