To confront the climate emergency, the amount we consume needs to drop dramatically. Yet every day we’re told to consume more. We all know about air pollution – but there’s a kind of “brain pollution” produced by advertising that, uncontrolled, fuels overconsumption. And the problem is getting worse. Advertising is everywhere, so prevalent as to be invisible but with an effect no less insidious than air pollution. A few years ago, an individual in the US was estimated to be exposed to between 4,000 and 10,000 adverts daily. UK spending on advertising almost doubled between 2010 and 2019 and, after a pandemic dip, the £23bn spend for 2020 is expected to rise by 15% in 2021. It’s woven into our personal communications whenever we use social media platforms. In public spaces, where we have little choice over where we look, adverts are invasive, appearing without our consent. And the trend towards digital billboards only exposes us ever more. Some big companies even boast about how “unmissable” digital screens are on busy roads, “captivating audiences” when drivers would be better off watching the road. Such roadside “out of home” advertising is set to grow by 25%, in 2021 and evolving advertising technologies that could use facial detection and tracking capabilities only heighten the sense of our privacy being invaded. Advertising works by getting under your radar, introducing new ideas without bothering your conscious mind. Extensive scientific research shows that, when exposed to advertising, people “buy into” the materialistic values and goals it encourages. Consequently, they report lower levels of personal wellbeing, experience conflict in relationships, engage in fewer positive social behaviours, and experience detrimental effects on study and work. Critically, the more that people prioritise materialistic values and goals, the less they embrace positive attitudes towards the environment – and the more likely they are to behave in damaging ways. Even worse, findings from neuroscience reveal that advertising goes as far as lodging itself in the brain, rewiring it by forming physical structures and causing permanent change. Brands that have been made familiar through advertising have a strong influence on the choices people make. Under MRI scans, the logos of recognisable car brands are shown to activate a single, particular region of the brain in the medial prefrontal cortex. Brands and logos have also been shown to generate strong preferences between virtually identical products, such as fizzy drinks – preferences that disappear in blind tests. Researchers looking to assess the power of advertised brands concluded that, “there are visual images and marketing messages that have insinuated themselves into the nervous systems of humans.” Indeed, some of the earliest work in this area concluded, “Scary as it may sound, if an ad does not modify the brains of the intended audience, then it has not worked.” Yet this is little known more widely. Through a combination of experience and ad exposure connected to emotional responses, brands and their logos become more “mentally available”. This happens through the development of new neural pathways reinforced by repeated encounters. Still other research demonstrates how exposure to different brands can influence behaviour, for example making them behave less honestly, or creatively. Customisable tools for neural profiling are now available to test the effectiveness of brands and logos on consumers, giving rise to what has become known as “neuromarketing”. That’s bad enough for adults, but children are now at the mercy of so-called “surveillance advertising”. It is estimated that by the time a child turns 13, ad-tech firms would have gathered 72m data points on them. The more data collected from an early age, the easier it is for advertisers to turn young children into consumer targets. Overconsumption in general, encouraged by advertising, has a climate and ecological impact. But advertising heavily polluting products and services, such as for fossil fuels, aviation and petrol-engined cars, is particularly damaging. It’s like the days when tobacco adverts were allowed. In 2018 the car sector is estimated to have spent more than $35.5bn on advertising in key markets globally, roughly equal to the annual income of a country like Bolivia. And, in recent years, advertising has pushed a major shift to people buying larger, more polluting SUVs. Regulators are very far behind the curve on these issues. The Competition and Markets Authority recently launched a public consultation to investigate misleading green claims. The advertising regulator, the Advertising Standards Authority, belatedly followed suit with a pledge to develop a code on greenwashing. But the ASA is a weak body with a narrow focus, paid for by the industry, which is effectively marking its own homework. Only 22% of adverts complained about are investigated by the ASA, and then only 2% of complaints are upheld, by which time the advertising campaign is usually over. Tackling “brain pollution” requires action equivalent to the campaign to end tobacco advertising. New checks and balances need to accommodate the natural concerns of councils and residents around climate, air pollution, environmental light pollution, the “attention economy”, mental health and the dominance of non-consensual adverts in public spaces. Advertising, the business of attention-seeking, has ironically avoided scrutiny so far. But as the climate crisis bites, its role is set to rise up the agenda. Campaigners are calling for legislation against high-carbon advertising, focusing on fossil fuel companies, petrol- and diesel-engined cars and aviation; at municipal level, places like Norwich, Liverpool and north Somerset are introducing measures to end high-carbon advertising; and an EU-wide campaign is now following a ban on the Amsterdam metro. Tackling brain pollution won’t just make us feel better, but help clear the air too.