We draw our moral lines in arbitrary places. We might believe we’re guided only by universal values and proven facts, but often we’re swayed by deep themes of which we might be unaware. In particular, we tend to associate the imagery and sensations of our earliest childhood with what is good and right. When we see something that chimes with them, we are powerfully drawn to it and attach moral value to it. This results from a combination of two factors: finding safety and comfort in the familiar, and what psychologists call “the primacy effect” – the first thing we hear about a topic is the one we tend to recall and accept. These tendencies contribute to the illusory truth effect: what is familiar is judged to be true. We go to war for such illusory truths, and sacrifice our lives to them. Few illusions reach us earlier than the story of the benign livestock farm. Pre-literate children are repeatedly exposed to farmyard tales. The impression these books and animations create – the animal farm as a place of kindness and harmony – seems extremely hard to shake, regardless of people’s later exposure to the realities of the industry. When we see imagery that reminds us of farmyard storybooks, we feel a glow of recognition. When we hear arguments that chime with these stories, we want to believe them. This, I think, explains the popularity of films that provide a rosy view of livestock farming, such as Kiss The Ground and The Biggest Little Farm. The latest contribution to the genre is a British film called Six Inches of Soil, now enjoying considerable success in independent cinemas. It follows the travails of three young farmers, “during the first year of their regenerative journey”. It’s well produced, makes some good points and tells some good stories. But it is also, in recounting the story we want to hear, fatally one-sided and, in crucial respects, wrong. Livestock farming ranks with the fossil fuel industry as one of the two most destructive industries on Earth. But because of those farmyard tales, reinforced by stories we’re told as adults in endless books and films celebrating the pastoral, we apply entirely different standards to it. Parts of this film could be clipped and used as advertisements for the most damaging of all livestock products: beef. Astonishingly, it was made not by meat companies but by environmentalists. It purports to show a cattle farm in Cornwall helping to prevent climate breakdown. Hannah Jones, from an organisation called Farm Carbon Toolkit, tells the farmer that, through the growth of his hedges and woodland, “you are removing more greenhouse gases from the atmosphere than you’re actually emitting”. The farmer, Ben Thomas, responds: “It’s such a great marketing tool for us.” I see this sequence as highly misleading. Before long the farmer will need to cut the hedges, releasing much of the carbon they’ve captured. Even in the film, we see him coppicing trees in his woods to make way for his cattle, which will oxidise most of the carbon they’d accumulated over 20 years. More importantly, the counterfactual scenario went unmentioned: if his cattle were removed from the land and it was allowed to rewild, far more carbon would accumulate, both above and below ground, and this would not be counteracted by the farm’s emissions. The government’s Climate Change Committee estimates that switching from grassland to woodland in England would eventually “increase the soil carbon stock by 25 tonnes of carbon per hectare” on average. Given that we reduce our land use by an average of 76% when we switch to a plant-based diet, the opportunity cost of using land for a cattle farm should feature in any discussion of whether or not it is saving carbon. The conversation moved on to soil. The film created the clear impression that Thomas had made even bigger savings across the year by increasing the carbon content of his soil. Pointing to a massive rise in soil carbon in Jones’s “table of emissions and sequestration”, he remarks, “So the hedgerows are amazing anyway, and the woods are pretty good. But the soil has absolutely smashed it.” This seemed extremely unlikely. First, there’s no academic study anywhere, meeting the necessary criteria, that shows sustained net greenhouse gas removal through soil carbon storage by a cattle farm. Recent research explains why such efforts have failed, and always will: partly because soil carbon soon saturates, while farm emissions continue. Second, the technologies required to demonstrate such an annual shift do not exist. Moreover, to establish that carbon has stayed in the soil, rather than simply cycling through it, you would need to show that the shift had been sustained for at least 20 to 30 years. When I asked Farm Carbon Toolkit how such a claim could be justified, it dropped a bombshell: the sequence, after being “edited down by the film-makers”, failed to make clear that they were discussing not the actual figures on the farm but “a modelled scenario”. In other words, though viewers were not told, the numbers weren’t real. When I challenged the film-makers, they accepted this, and told me “it’s possible” that they might change the editing for the video-on-demand release of the film. I hope they do. In the meantime, cinema audiences should be warned that it creates a misleading impression. These sequences look to me like moo-woo: the oft-repeated and oft-debunked story that cows can protect the atmosphere. It’s as if environmentalists had made a film about artisanal coal mining, told heroic stories about the workers, and allowed their viewers to believe that coal mined this way is good for the planet. This story is perfectly aligned with the livestock industry’s greenwashing. Like the film, it liberally uses the term “regenerative”, which means whatever you want it to. It wrongly claims that cattle can be carbon neutral or carbon negative and that beef-eating can be eco-friendly. Such persuasion narratives have real and massive impacts. The European Union is currently deleting its nature restoration proposals in response to farm lobbying. In the UK, a culture war against Natural England, whipped up by livestock farmers on Dartmoor and their supporters in parliament, threatens the protection of our nature sites. No other industry has benefited as much from unpaid propagandists: well-meaning people unwittingly acting on its behalf. A magnificent aspect of our humanity is that we can change our beliefs in response to evidence. It’s time to exercise this faculty, and put away childish things. George Monbiot is a Guardian columnist