Guest essay by Iain Aitken

An availability cascade is a self-reinforcing process of collective belief formation by which an expressed perception triggers a chain reaction that gives the perception of increasing plausibility through its rising availability in public discourse.

Perhaps the most extraordinary aspect of the whole ‘climate change debate’ is the way that the (non-sceptical) public consciousness has been captured by two very simple, easy-to-understand and certain ‘scientific facts’:

1. Climate change has (with absolute certainty, because the science is settled) occurred because of man-made carbon dioxide emissions (and it has occurred only because of man-made carbon dioxide emissions – nature had nothing to do with it)
2. Climate change catastrophe will (with absolute certainty, because the science is settled) result if we do not drastically reduce our carbon dioxide emissions.

In Tweets/soundbites, we often see:

‘There is a man-made climate change crisis’ or ‘Climate change is real, man-made and dangerous’.

To question these ‘scientific facts’ is to be a ‘climate science denier’.

Despite the fact that both these ‘scientific facts’, as stated, are (with absolute certainty) scientific hogwash and despite the fact that I doubt it would be possible to find a single climate scientist in the world who would endorse either ‘scientific fact’ (even the Intergovernmental Panel on Climate Change, the ‘world authority on climate change’, and most alarmist of scientific bodies, would certainly not endorse either statement) these two beliefs (because that is all they are) seem to have become memes (beliefs that spread by cultural acquisition, e.g. peers, media). It is what the (non-sceptical) public think the scientific authorities are saying.

These beliefs have become memes in that, when questioned, members of the general public who claim to hold these beliefs may say they do so because ‘their Facebook friends say they are true’, or ‘newspapers say they are true’, or ‘politicians say they are true’, or ‘scientists say they are true’, i.e. it is ‘received opinion’. In this case they have not arrived at these beliefs through their own reasoning or even been argued into them by the reasoning of others; instead they ‘just know’ they must be true because ‘everyone else’ ‘just knows’ they must be true. After all, it is what all intelligent, responsible, rational and reasonable people believe. Isn’t it? Only the stupid, irresponsible, irrational and unreasonable climate science deniers question it.

This process has been characterised by psychologists as an ‘availability cascade’. Paraphrasing Wikipedia, this is a self-reinforcing cycle that explains the development of a collective belief (or meme) in a man-made climate change crisis. The idea that a great many phenomena (whether they be melting icecaps, rising sea levels, ocean acidification, floods, droughts, hurricanes, snowstorms, heatwaves, shark attacks or the rise of Islamic State) that actually have unrelated and complex causes can be explained by one, simple, easily understood cause, gains rapid currency in the popular discourse by its very simplicity and by its apparent insightfulness. Its rising popularity triggers a chain reaction within the social network: individuals adopt the new insight that we are experiencing a man-made climate change crisis because other people within their social network have adopted it, and on face value it sounds plausible (after all, we have been adding carbon dioxide to the atmosphere and it is a greenhouse gas and so it must cause global warming). The reason for this increased use and popularity of the ‘man-made climate change crisis’ idea involves both the ‘availability’ of this idea in the media (it’s hard to go through a day without someone on the radio, on TV or in a newspaper mentioning it as though it is simply a ‘fact’ in one form or another), and the need of individuals to conform with this idea, regardless of whether they in fact fully believe it.

Their need for social acceptance and political correctness, coupled with the apparent sophistication of the new insight, overwhelm their critical thinking. Imitation and conformity, rather than critical analysis and independent thinking, are at the heart of a meme. The public concern then puts pressure on political policymakers to make policies to address the public concern. The public then see confirmation that their concern over the man-made climate change crisis must be valid – after all, the politicians are enacting policies to address it. It is a self-reinforcing loop of irrationality based on a very poor understanding of what the science actually says – in fact even a very poor understanding of what the scientific authorities actually say.

The availability cascade around the ‘man-made climate change crisis’ idea has been so extreme that, despite the fact that common sense alone should tell us that the idea is fantastical (that after 4.5 billion years of having no material effect on the Earth’s climate at all we humans have, in the last few decades, taken control of it) it nevertheless is regarded as a fact by many. It’s very easy to ‘just believe’ in the man-made climate change crisis whilst independent critical analysis of the subject requires a great deal of time and effort to understand the science and arguments (not to mention a requirement to care not a whit what people think of you for your unorthodox and politically incorrect views or that your views are apparently totally add odds with all of the ‘authorities’). For many members of the public (and, probably, the vast majority of politicians and journalists), especially those who struggle to remember even the basics of school science, the science and arguments can appear overwhelmingly complex and difficult and so there is a huge temptation to simply ‘trust the authorities’. Which of course plays directly into the hands of the authorities. Yet whilst the scientific authorities are doubtless delighted that the public and politicians hold these beliefs not even they would publically endorse them – all they need do is stay prudently silent and let the deluded availability cascade continue.

It is tempting for sceptics to call these two beliefs ‘myths’ rather than ‘memes’; however that would imply that they are entirely made-up and without any truth. But let us say that the hypothesis that climate change is caused by man-made carbon dioxide emissions is in the dock on a charge of perjury and I am the lawyer for the defence. I would simply explain to the jury that even the most sceptical of scientists would accept that man-made carbon dioxide emissions contribute to some extent to global warming and hence climate change. Therefore it is literally true that ‘man-made carbon dioxide emissions cause climate change’. Even if they contributed just a thousandth of one percent to global warming they would still ‘cause climate change’. Even if the burning of fossil fuels created global cooling (through the additions of aerosols and soot to the atmosphere) that far outweighed the global warming effect of the burning of those fossil fuels, nevertheless man-made carbon dioxide emissions still ‘cause climate change’ (albeit the net effect of creating those carbon dioxide emissions would actually be global cooling). Perhaps foolish members of the public misinterpret what the word ‘cause’ means, assuming it means ‘is entirely responsible for’. But my client can hardly be held responsible for that.

These beliefs are ludicrously simplistic and, in fact, scientific nonsense. The ‘educated guess’ of the IPCC (well, a few dozen alarmist scientists and computer modellers at the IPCC) is that probably more than a half of recent global warming is man-made, which is a far cry from the first belief. And note that ‘probably more than half’ is a highly subjective opinion – it’s not, for example, 73% (±3%). And this highly contentious opinion is predominantly based, not on empirical scientific evidence, but on virtual world evidence from dubious climate change computer models. The rest of the warming must be natural – unless, of course, you believe that climate change is actually caused by aliens (as presciently explained by John Wyndham in his 1953 classic SF novel, The Kraken Wakes). Furthermore, given the huge scientific uncertainty over the ‘correct’ value for ‘equilibrium climate sensitivity’ (a key indicator of how much warming is associated with a given level of carbon dioxide emissions) a huge cloud of uncertainty hangs over the second belief – if climate sensitivity is low enough then even ‘worst case’ future carbon dioxide emissions would be unlikely to cause ‘dangerous’ (let alone ‘catastrophic’) climate change. However, so long as politicians and the media continue to endorse these beliefs (if only tacitly), the public will continue to believe them. The politicians endorse them by using the oldest political trick in the book: come up with a short, simplistic slogan (e.g. ‘Crooked Hillary’) – and then repeat it over and over and over again. In climate change the slogan is ‘climate change is real, man-made and dangerous’ – and this is repeated over and over and over again. Is it actually true?

Well, say the politicians, 97% of scientists agree with it (nonsense as that claim is) so it must be true, mustn’t it? These politicians may be largely scientifically illiterate and know next to nothing about climate science (other than the little they have been told by their scientific advisers) but when the ‘world authority on climate change’, the IPCC, apparently says something is so and almost every scientist on the planet apparently agrees with them then it must be true, mustn’t it?

This is an ‘appeal to authority’; but as Leonardo da Vinci said, ‘Anyone who conducts an argument by appealing to authority is not using his intelligence’.

Nevertheless it is an understandable position for them to take (provided they blindly trust authority more than reason and scientific evidence). Ending this mother of all availability cascades would (minimally) require the politicians and journalists and public to understand that their beliefs are rather more based on faith and emotion than science and reason and to take the considerable time and trouble to actually critically investigate and understand the science. It would require them to lay aside their simple, easy-to-understand certainties for complex, hard-to-understand uncertainties. Don’t hold your breath.