Wednesday 29 November 2017 17.17 GMT
The body of evidence supporting human-caused global warming is vast – too vast for climate denial blogs to attack it all. Instead they focus on what a new study published in the journal Bioscience calls “keystone dominoes.” These are individual pieces of evidence that capture peoples’ attention, like polar bears. The authors write:
These topics are used as “proxies” for AGW [human-caused global warming] in general; in other words, they represent keystone dominoes that are strategically placed in front of many hundreds of others, each representing a separate line of evidence for AGW. By appearing to knock over the keystone domino, audiences targeted by the communication may assume all other dominoes are toppled in a form of “dismissal by association.”
Basically, if these bloggers can create the perception that the science underlying polar bear or Arctic sea ice vulnerability to climate change is incorrect, their readers will assume that all of climate science is fatally flawed. And blogs can be relatively influential – surveys have shown that blog readers trust them more than traditional news and information sources.
Denier blogs and science-based blogs “diametrically opposite”
In this study, the authors examined the arguments made by 45 denier blogs and 45 science-based blogs regarding the impact of human-caused global warming on polar bear populations and Arctic sea ice extent. They found that the science-based blogs all showed that Artic sea ice is declining, and nearly all said that global warming threatens polar bear populations.
Conversely, the denier blogs nearly all denied that Arctic sea ice is declining or argued that we can’t predict how it will change in the future, and that polar bears aren’t threatened and/or will adapt to climate change.