In a previous article on The Conversation, Stephan Lewandowsky asked, why do people reject science? I’m going to take a slightly different angle and consider how people are able to reject climate science in the face of strong evidence.
A growing body of research has found that when a person’s worldview is threatened by scientific evidence, they interpret the science in a biased manner. One issue where this influence is strongest is climate change.
For supporters of an unregulated free market, regulating polluting industries to reduce global warming is so unpalatable that they are far more likely to reject that climate change is happening.
The mechanism by which ideology such as this influences our scientific views is confirmation bias. We place greater weight on evidence that confirms our beliefs, while ignoring or resisting conflicting evidence. This can be a challenge when confronted with a convergence of evidence and a scientific consensus, but confirmation bias is up to the task. Let’s look at some examples.
The most common manifestation of confirmation bias is cherry picking, where one carefully selects a small piece of data that paints a friendly picture and overlooks any inconvenient evidence.
How do we spot cherry picking? It’s important to remember that there is no 'their evidence' versus 'our evidence'. There is only the full body of evidence.
If someone arrives at a conclusion from carefully selected evidence that contradicts the conclusion drawn from the full body of evidence, that’s cherry picking.
Cherry pickers ignore the fact that our planet is currently building up heat at the stunning rate of around three Hiroshima bombs per second. Instead, they focus on short periods of the surface temperature record. This record bounces up and down from year to year as the ocean exchanges heat with the atmosphere, meaning that it’s possible to find any short period during a long-term warming trend where temperatures fall briefly. Meanwhile the planet continues to build up heat – around 250 Hiroshima bombs worth since you started reading this article.
Confirmation bias also influences which sources of information we put our trust in. People tend to attribute greater expertise to people who share their values and beliefs. We’re drawn to those who tell us what we want to hear.
So what happens when 97 out of 100 of climate scientists agree that humans are causing global warming?
Those who reject the scientific consensus lavish their attention on the 3 per cent minority, magnifying their significance and turning a blind eye to the 97 per cent of scientific experts.
So how can ignoring the 97 per cent be justified? Two words: conspiracy theory. There are a range of conspiracy theories out there, from sinister attempts to control the planet with a one world government to claims that virtually every climate scientist on the planet is falsifying their data for financial reasons, a form of global groupthink.
Roy Spencer, one of the minority of dissenters remaining in the climate science community, said:
If scientists are promised a career of financial support to find evidence of manmade climate change, they will do their best to find it.
Let’s look at Spencer’s claim in greater detail, keeping in mind the key characteristic of a conspiracy theorist: exaggerated claims about the omnipotence of the conspirators.
For human-caused global warming to be falsely manufactured, scientists would have to falsify the satellite data finding less heat escaping to space and fudge the measurements of downward infrared radiation that confirm an increased greenhouse effect.
Both the satellite and weather balloon records that find a cooling upper atmosphere along with a warming lower atmosphere (a signature of greenhouse warming) would have to be doctored. The fact that winters warm faster than summers and nights warm faster than days, both fingerprints of greenhouse warming, would have to be fabricated in a number of different temperature records.
What drives Roy Spencer to espouse the implausible theory that thousands of scientists spanning dozens of countries are engaged in a global fabrication of data?
His job at the University of Alabama in Huntsville is to analyse satellite measurements of the atmosphere, but he sees himself a little differently, describing his role as:
… a little like a legislator, supported by the taxpayer, to protect the interests of the taxpayer and to minimize the role of government.
Spencer personifies the principle that ideology biases the way we process evidence.
One of the loudest contrarian voices in Australia is Ian Plimer, a geologist who has not published a single peer-reviewed paper on climate change. Nevertheless, he is the go-to guy for public voices such as Gina Rinehart, Cardinal George Pell and Tony Abbott.
Why do these public figures favour a non-peer reviewed non-expert who has a long history of self-contradiction? The psychological research on which experts we prefer tells us why. Confirmation bias sways us towards those voices that tell us what we want to hear.
Another method of avoiding the consensus of evidence is through the use of logical fallacies. The straw man fallacy is confirmation bias applied through logical argument, misrepresenting an opponent’s position by focusing on their weaker arguments while ignoring their stronger points.
An example is the accusation that climate scientists in the 1970s predicted global cooling. When you look at the actual peer-reviewed research in the 1970s, the papers predicting global warming from greenhouse gases far outweighed papers predicting cooling. Somehow, the warming papers escape the attention of those who reject climate science.
A common logical fallacy employed by climate contrarians is the “non sequitur”, Latin for “it does not follow”. This applies to arguments where the stated conclusion is not supported by its premise.
The most cited example is “climate has changed naturally in the past therefore current warming must be natural”.
A recent variant argues, in response to this year’s record low in Arctic sea ice, that ice has been low in the past. This is logically equivalent to investigating a corpse with a gunshot wound and ruling out murder because people have died from natural causes before.
To reduce the influence of those who reject the science, confirmation bias and misleading rhetorical arguments need to be exposed. Now is as good a time as any to start practising so I recommend beginning with the inevitable deluge of comments to this article. Look for cherry picking, conspiracy theories, comments magnifying the significance of dissenters (or non-experts) and logical fallacies such as non sequiturs.
You might think those who reject climate science would refrain from employing these methods in such an obvious fashion. But consider the Arctic sea ice example. On one contrarian climate blog, a commenter predicted five ways that people would avoid the inevitable implications of the precipitous drop in Arctic sea ice. Climate sceptic blogger Anthony Watts fulfilled all five predictions.
Such reactions go to show that science rejection is an instinctive, emotional and ideological response to evidence that appears to threaten certain deeply-entrenched worldviews.
John Cook is currently the Climate Communication Fellow for the Global Change Institute at the University of Queensland.