News items on climate change are now regularly flooded with negative online comments (see, for example, http://go.nature.com/Lfigec). These tend to have certain features in common.
The comment writers struggle to find words that are emphatic enough to express their contempt for anthropogenic global warming and for the 97% or so of active climate scientists who accept its reality. They feel attacked, lied to and conspired against: they are intensely angry. Their comments are often pervaded by heavy sarcasm. In their view, climate scientists are not merely mistaken, but foes of truth and liberty. They see themselves as fighting a powerful enemy — a posture that can be addictive.
These comment authors rarely engage with the original science (in the above example, an article in Geophysical Research Letters). They have unplugged from the scientific discourse because they believe it to be driven by crypto-environmentalist (or crypto-communist) ideology. This conviction characterizes fundamentalisms: a true believer does not need to engage, they already know. The denialists charge that it is the scientists who refuse to consider the evidence; alternatively, scientists know all about it and are lying. The parallels with some creationist rhetoric are striking.
Certain standard fallacies and counterfactuals are held by these commenters as irresistible 'gotchas' — any one of which makes the idea of human-induced global warming absurd (and further thought unnecessary). For example, a popular line of argument is that because climate has changed in the past without human input, humans cannot be changing it now. Mistaken beliefs are held that scientists on the Intergovernmental Panel on Climate Change, climate modellers and other researchers ignore factors such as water vapour, urban heat islands and the Sun.
The peculiar danger of any full-blown conspiracy theory is that it can become an intellectual black hole, a one-way trip. Hope lies mostly in keeping people out of the hole, rather than trying to rescue those who have fallen in.
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