Moderators of a science forum on reddit have banned climate change sceptics from commenting because they do not add to the debate and behave in an aggressive manner.

Writing for, Nathan Allen, a PhD chemist and a moderator of the reddit forum /r/science, explained why he and the other moderators had made the decision to delete comments made by climate change deniers.

"On our little page, scientists and nonscientists can connect through discussions on everything from subatomic particles to interstellar astrophysics.

"I consider it a microcosm, representative of the vast range of views that can be supported by empirical evidence. Importantly, it provides the same window for those who are not scientists, who do not regularly talk with PhDs, and who may be unfamiliar with how science is discussed by scientists."

Allen said that normally users discuss scientific topics through linking to peer-reviewed studies to support their arguments and there is a shared level of respect for other people's opinions. However, he said climate change skeptics do not adhere to this "decorum".

"Instead of the reasoned and civil conversations that arise in most threads, when it came to climate change the comment sections became a battleground. Rather than making thoughtful arguments based on peer-reviewed science to refute man-made climate change, contrarians immediately resorted to aggressive behaviours."

He said the skeptics are not like "internet trolls" looking to upset people, but rather they were truly "blind to the fact that their arguments were hopelessly flawed.

"As a scientist myself, it became clear to me that the contrarians were not capable of providing the science to support their 'skepticism' on climate change. The evidence simply does not exist to justify continued denial that climate change is caused by humans and will be bad.

"There is always legitimate debate around the cutting edge of research, something we see regularly. But with climate change, science that has been established, constantly tested, and reaffirmed for decades was routinely called into question.

'Worst of all, they didn't even get the irony of quoting oil-funded blogs'

"Over and over, solid peer-reviewed science was insulted as corrupt, while blog posts from fossil-fuel-funded groups were cited as objective fact. Worst of all, they didn't even get the irony of quoting oil-funded blogs that called university scientists biased."

Allen explained that the moderators took the decision to use "proactive moderation" around a year ago and that since then, the debate on climate change has been much improved.

"As a site, reddit is passionately dedicated to free speech, so we expected considerable blowback. But the widespread outrage we feared never materialised, and the atmosphere greatly improved," he said.

Concluding, he added: "If a half-dozen volunteers can keep a page with more than four million users from being a microphone for the antiscientific, is it too much to ask for newspapers to police their own editorial pages as proficiently?"

Following the publication of Allen's report, Telegraph columnist Brendan O'Neill said reddit had "ripped its own reputation to shreds" for denying people the right to voice their opinion.

Reddit defended the moderators' decision, saying thousands of subreddits on the site – including /r/science – are run by moderators and they have the right to create policies regarding comments.

"Reddit didn't ban anyone," a spokesman said. "The moderators of one of the hundreds of thousands of subreddits made a new policy as is their prerogative."