One of the first targets the industrial climate disinformation machine started attacking was the scientific consensus that fossil fuels cause dangerous climate change. Ad men knew, even back in the 1950s, that the public's understanding of a scientific issue hinged on what we perceived the experts to believe about it. Even just a lone voice saying something wrong, but loud was enough to give people something to hang their hat on.
It's no great surprise, then, that modern studies reveal the extent to which public sentiment on climate is shaped by how people understand the scientific consensus. A person's understanding of the overwhelming nature of the consensus on climate is a "gateway belief" — something that, once you know about it, makes you much more open to climate policy.
Now the latest study on the issue confirms that even deniers are influenced by consensus! In "Communicating the Scientific Consensus on Climate Change: Diverse Audiences and Effects Over Time," lead author Matthew Goldberg and coauthors (including Sander van der Linden and Anthony Leiserowtiz) measure how persuasive consensus messaging is to "oppositional audiences," how long that effect lasts, and the predictive factors on whether or not the effect will last.
They found that, "Although consensus treatment effects decay over time, 40% of the original treatment effect remains 26 days later." This means that there's likely some relatively long-term impact to telling people climate scientists are nearly unanimous on the cause of the crisis.
"Additionally," the abstract states, "the treatment effect is most durable among people Doubtful or Dismissive of climate change."
So, it's actually most effective on those who most need to hear it! Wonderful!
In a (free, un-paywalled) preprint draft, you can find that, when asked to estimate what percentage of scientists have "concluded that human-caused global warming is happening," the Alarmed audience moved the least because they had the highest estimate to begin with. Alarmed people estimated an 87% consensus before being told the reality, and then updated that to 92% after the treatment. The Concerned went from 77 to 88%, and the Cautious from 69% to 80% — spreads of just 5-10%.
But the Doubtful and Dismissive started with even lower estimates of consensus — 61% and 53%, respectively. After being exposed to the treatment message that “97% of climate scientists have concluded that human-caused global warming is happening," those numbers jumped.
While Dismissives apparently begrudgingly admitted to a 68% consensus after being told about it, increasing their estimate by 15%, the Doubtful's estimate went up even further — gaining 19 points, from a 61% estimate to 80%.
That put the Doubtfuls' estimate three points higher than the Concerned were before treatment. While it's not impossible to stick to thinking something you tell yourself has the support of "only" two-thirds of the scientific community, it's certainly harder than if you know it's half.
Interestingly, the Dismissives before treatment thought their position was in the scientific minority against the 53% consensus.
…They already know they've lost!
Which is why the fossil fuel industry desperately needs to keep telling them otherwise. When the researchers went back 26 days later, they found that those who had been exposed to climate disinformation had reverted back to their pre-treatment levels, while those who had heard additional reminders of the consensus remained more accurate in their stated beliefs.
"Thus," the paper concludes, "in competitive information environments, it is important for scientific communication campaigns to be prepared to play both offense and defense."