Should news organisations give climate change deniers the opportunity to make the bald assertion in the letters pages and in comment threads that climate change is not caused by man? One major newspaper has come down very firmly on the side against publishing letters in that vein.

The Los Angeles Times made the announcement on 5 October. Three days later Paul Thornton, the paper's letters editor, explained the background to the decision. He wrote that he gets many letters from those who deny global warming, and went on to explain that he was no expert, but had to rely on scientists who "have provided ample evidence that human activity is indeed linked to climate change. Just last month, the Intergovernmental Panel on Climate Change … said it was 95% certain that we fossil-fuel-burning humans are driving global warming. The debate right now isn't whether this evidence exists (clearly, it does) but what this evidence means for us.

"Simply put, I do my best to keep errors of fact off the letters page; when one does run, a correction is published. Saying 'there's no sign humans have caused climate change' is not stating an opinion, it's asserting a factual inaccuracy."

The letters editor of the Sydney Morning Herald has come to a similar conclusion. Where should the Guardian stand, knowing that any debate on its position will elicit, quite reasonably, someone quoting CP Scott stating that "the voice of opponents no less than that of friends has a right to be heard"?

Graham Readfearn, who writes a blog hosted by the Guardian about the environment, climate change, climate change deniers and lobbyists, believes that Scott was talking about the delivery of news rather than the publishing of people's opinions.

He said: "I wonder how the paper would treat a letter from someone who wrote that there's no evidence that vaccinations are good for children's health, or that smoking might not cause cancer? These views are easily found on the web, but I suspect they'd go straight in the bin at the Guardian.

"Saying that, I suppose this all depends on whether the paper sees the letters page as a place that should reflect the views of the readers at any given time, regardless of what they are, or whether there's an element of fact-checking woven into that."

Guardian moderators say there are no rules against comments by climate change deniers as such but they take a very strict line when dealing with threads in the environment section as comments which deny climate change can be used to derail threads and cause discussions to go off topic.

Sometimes the identity of a person expressing an opinion is as interesting as the thing being expressed. If a member of the royal family wrote a letter denying that climate change exists the Guardian would almost certainly run it.

Nigel Willmott, the Guardian letters editor said: "We are the letters page, we're there to reflect our readers' views in all their diversity, so we consider every letter. But there are views that it's hard to think of any circumstance in which we would run them – from racist opinions and Holocaust deniers, to those claiming to have been implanted with listening devices by the secret services (more correspondents than you might think!).

"We receive few, if any, letters denying outright that climate change is happening – occasionally someone pointing to recent years where the rate of increase has plateaued.

"But there are some who accept human causes but question the anti-fossil fuel strategies linked to that. If you believe in a Popperian [after Sir Karl Popper] framework of science that sees all scientific truths as provisional but not arbitrary, then I think you should never absolutely rule out views heretical to the scientific orthodoxy, even if cautious to give them space.

"So I would be unhappy about an absolute ban on those who might be grouped together as climate change deniers, but would need to see a strong case to run anything from them (and know something about what commercial interests they might be linked to)."

I think that's a sound policy which reflects the accretion of evidence.