Effective actions to reduce our carbon footprint

On 26 October 2022, the newspaper Libération published an article about the average carbon footprint of a French person over a year. Presented as an original infographic, it reuses the averages by emission category from the science and life blog ‘Ravijen’. These results roughly corroborate those of Jean-Marc Jancovici’s consultancy (Carbone 4), published ten years earlier in Terraeco, except that food came first rather than fourth.

At the end of 2021, the MyCO2 website, powered by Carbone 4, published its reference chart of the average French carbon footprint [4], specifying that this is the most complete and precise scope to date [5]. Taking stock of the psychological impacts of climate change, a new article from Polytechnique insights [6] tells us that each additional degree would bring approximately a 1% increase in the suicide rate.

The hypothesis of variation depending on scope

The difference in the food footprint between the results presented by Ravijen [2] and Terraeco [3] would correspond to a reduction in meat and dairy consumption from 1,843 to 1,552 kg CO₂ equivalent per person per year. Unfortunately, it is not a reduction in meat (or dairy) consumption that explains it, as this is still not falling in France [7]. The difference more likely comes from different data being taken into account as the scope varies, since the same emission items can be allocated to different categories. To be sure, we would need the detail of the calculations and the input data used in each category, but unfortunately we do not have access to them.

Making sectors visible to identify actions

The whole value of the Libération article is that it makes visible the fact that the transport, housing and food sectors are responsible on average for 70% of our carbon footprint (nearly three quarters). Although our carbon footprints all vary in size, a national average by sector helps us better understand our own carbon balances. We can identify the categories responsible for most of our emissions and target our action. We therefore have every interest in identifying, in each of these three sectors, the most effective levers for reducing our carbon footprint.

Note also that two categories with a common credible alternative could be grouped together to make it easier to identify the best action. Here, for example, meat and dairy products both come from livestock farming. Yet shifting diets towards plant-based foods, by replacing animal products with plant-based equivalents, offers an alternative to both, which could be grouped under the category ‘animal products’. Promoting it therefore provides a clear common response that is easier to distinguish.

For transport, the article mentions that the manufacture and use of the private car are responsible for most emissions (if you have one, of course). Failing that, cycling is by far the best lever, but one can, for example, prioritise buying second-hand and sharing vehicles. For housing, accounting for 60% of energy use [8], heating is the main emitter. In addition to improving insulation where possible, replacing an open fireplace, an oil-fired or gas boiler with a masonry heater (an efficient log-burning stove that improves thermal comfort) can be a good solution. Finally, for food, replacing livestock products with equivalent plant-based products is the action with the greatest potential to reduce greenhouse gas emissions that we can take in rich countries, cutting annual emissions from agricultural production by 61% and doubling our climate dividend [9]. Globally, a rapid phase-out of animal agriculture would even have the potential to stabilise greenhouse gas levels for 30 years and offset 68% of CO₂ emissions this century [10].

Prioritising to increase impact

Of course, there are many other ways to reduce our carbon footprint. However, it is essential to clearly identify the most effective ones, that is, those most likely to reduce it. Take food, for example, which concerns all of us on a daily basis and which, when it is not a blind spot, is poorly understood. In France, according to a European study published in 2018, animal products alone are responsible for around 85% of the sector’s emissions [11]. At the same time, another 2018 study tells us that the lost food opportunity caused by the high resource intensity of animal products is greater than food waste [12], which nonetheless amounts to a third of global production. The researchers point out that, on average, animal-based production requires about ten times more resources and emits ten times more greenhouse gases than plant-based production. These findings are confirmed by the latest reference study [13], which states that global greenhouse gas emissions from animal products are twice as high as those from plant products, even though they provide us with only 18% of calories and 37% of protein [14]. Worldwide, packaging (5.5%), transport (4.8%), retail (4%) and food processing (3.5%) account for only 17.8% of the sector’s emissions [15]. Moreover, according to this life cycle assessment meta-analysis [16] covering 742 agricultural systems, discussed on the Our World in Data website [17], organic systems produce greenhouse gas emissions similar to those of conventional systems.

It is therefore more worthwhile to change the type of diet (plant-based rather than animal-based) before eating local, seasonal, zero-waste and even organic. The idea is obviously not to pit actions against one another, but given our limited capacity for change and the climate emergency, we are better off prioritising the actions most capable of limiting climate risk.

Implementation intentions to the climate’s rescue

The social psychologists Susan Fiske and Shelley Taylor coined the term ‘cognitive miser’ to describe the way in which, when competing options are on offer, people choose the one that produces the greatest cognitive effect for the least mental effort [18]. In the Xenius programme “Sauver la planète : pourquoi est-ce si difficile ?” [19], the environmental psychologist Ellen Matthies takes up this theory, telling us that human beings tend to think, analyse and perceive things by relying on the best-known cognitive biases. For real change to happen, the brain must first register new behavioural pathways. She explains:

This is the role of one very particular brain structure: the basal ganglia. When we learn something new, such as driving, we repeat the same movements over and over. This leads to the formation in our brain of what might be called well-trodden paths. Each time we take them, they grow stronger. Little by little, our brain records this process in the basal ganglia, which allows us to develop automatic responses. We drive without needing to think much. The problem is that once ingrained, these automated behaviours are hard to change.

Ellen Matthies illustrates implementation intentions with this example:

To actually take the bike rather than the car, you need to picture your next outing, imagining yourself going to fetch your bike and setting off. The more often you do this, the more effective it is. The brain would record this new behaviour more easily because we would already have thought through our plan of action before even being faced with the situation. At first, it is advisable to set modest goals. A major problem is that our environment is full of information that floods our brain, making any new implementation difficult. Unfortunately, we cannot form implementation intentions for every area of behaviour without risking overload. It is therefore better to start by focusing on a single goal.

Social psychology to help with behaviour change

More broadly, the researcher Mélusine Boon-Falleur and her colleagues published a study in 2022 [20] proposing to draw on social cognition to promote effective climate change mitigation. The example of food is taken up there.

There are excellent reasons to adopt a plant-based diet: it is generally better for health and the environment [21], offers effective protection against cardiovascular disease [22] (the leading cause of death worldwide [23]), can add up to 13 years to life expectancy [24] and is three times cheaper than the benchmark diet in the wealthiest countries once negative externalities are taken into account [25].

Although plant-based alternatives are becoming increasingly widespread in most developed economies (though not available in every region’s grocery shops and restaurants [26]), we must acknowledge that we continue to eat animal products, even despite the negative impacts we may be aware of. Unfortunately, information alone is not enough to change our behaviour, because significant sociotechnical and psychological obstacles persist [27]. Yet we know that we should systematically adopt the most effective behaviours to reduce our carbon footprint. This is precisely where social psychology can help us [28].

By sustaining the consumption of animal products, the current norm exerts a social pressure that works against changing our behaviour [29]. While in private we may think it is important to reduce our consumption, we may wrongly believe that most people think otherwise. The experiments of Gregg Sparkman, a researcher in experimental and social psychology, and his colleagues show that knowing the dynamic norm, that is, here, the number of people willing to change their diet, encourages behaviour change, even when that change goes against the norm [30] [31].

In short, their study highlights the value of understanding the dynamics of social norms in order to steer groups towards a moral tipping point, a threshold beyond which a moral obligation drives us to adopt virtuous behaviours [32]. Targeting the individuals who accelerate the adoption of a new norm through network analysis, or promoting effectiveness as a moral norm by adopting an ‘effective environmentalist mindset’, seems to be a good strategy. Lastly, it also encourages further research into the acceptability of policies as essential tools, such as the carbon tax, and into the factors that influence the perception of fairness.

Climate change as a social dilemma

Social motivation to adopt pro-environmental behaviours is a powerful tool for giving us a sense of purpose and encouraging us to change. Faced with a social dilemma, we gauge social norms in order, among other things, to manage our reputation. We also implicitly calculate what seems fair to us so as to benefit from cooperative efforts. We weigh the advantages of departing from the norm against the cost of not conforming to the behaviour of others. If criteria such as observability or fairness are not met, we tend not to cooperate. With this in mind, improving our understanding of the cognitive mechanisms underlying our cooperation, so as to mitigate the effects of climate change, would help remove certain obstacles to changing our behaviour.

Finally, a new study [33] found that teaching philosophy changes opinions on moral controversies by reducing reliance on intuition. Change of opinion was predicted exclusively by a decrease in reliance on intuition. At the same time, the results suggest that reasoning and evidence can bring about moral change: by calling into question the reliability of intuition and emotion. Philosophy facilitates critical reflection on moral questions by exposing students to arguments and evidence – students can learn to rely more on their own deliberation or to disregard their intuition. This work suggests that moral education can help to shift intuitively entrenched moral opinions – and, hopefully, to promote moral progress – one argument at a time.

The role of societal tipping points in the transition

Behaviour change is generally slow, particularly when it comes to culturally ingrained and socially dependent behaviours such as eating. Yet the great challenges we face demand an unprecedented degree of food system transformation. This is why a new study [34] introduces societal tipping points – a concept that can trigger large-scale behaviour change – to foster the food transition.

Although it may be rapid and influenced by humans, a tipping point is unlikely to be triggered by a single event, actor or intervention, but rather by many interdependent societal processes. Short- and long-term actions both contribute to it. For example, in triggering societal tipping points to change eating habits, it is necessary to make efforts at the political level (with decision-makers actively exerting influence and making choices) and to exert public pressure, for example through social movements or demonstrations, which can in turn influence consumer behaviour.

In their study, James Andreoni and his colleagues [35] state that information which fosters a shared understanding of the benefits of change helps society abandon harmful norms. Knowing how many people have already changed their minds, and knowing the exact impact of products, through an eco-score for example, can encourage behaviour change. They also show that the instigators of change tend to be more risk-tolerant and to dislike conformity more.

While every tonne of carbon emitted contributes to global warming, the latest IPCC report [36] has reminded us that every tenth of a degree counts.

References

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