Towards a sustainable society, one behaviour at a time


Dr Julia Terlet

Not everyone agrees on the importance of individual behaviour change as a way towards a
more sustainable society. Generally, two types of arguments run against it. The first is that
small acts don’t have any impact. The second is that governments and businesses should be
responsible for making important changes, and shouldn’t push their responsibility onto
individuals. The truth is technological progress and political decisions aren’t sufficient to
effect change to the scale that we need. These initiatives need to be complemented by
individual behaviour change to have enough of an impact.

The contribution of individual behaviour change

“I think one of the challenges of the transport decarbonisation plan is that there’s a soft implication
that everything can be achieved through technology. But I think we all know that there needs to be
some behavioural change as well”, recently said Martin Dean, Managing Director at the Go-Ahead
Group, at COP26 as he was highlighting the importance of considering individual behaviour change.

The French consultancy Carbone 4 estimates that actions such as cycling, not eating meat and flying
less could help reduce our carbon footprint by 25%. Adding to that, investments such as switching to
an electric car or a new boiler, or opting for thermal renovation, could lead to further reductions.
Altogether, our collective carbon footprint could be cut by up to 45% through individual action. And
even a moderate, more realistic level of engagement could reduce emissions by 20% if it was
adopted by all. This is all the more important for inhabitants of the Global North, who live in countries
responsible for 92% of excess emissions.

But the impact of individual behaviour change goes beyond that. First, it is not just about climate
change and reducing CO 2 emissions. Our behaviours also have an impact on other environmental
issues, such as pollution, the depletion of natural resources, and biodiversity loss. The ecological
transition is a mix of complex interdependent mechanisms that all include an individual element.
In addition, individual behaviour change can be a catalyst for bigger, societal changes. Stuart
Capstick, Deputy Director of the Centre for Climate Change and Social Transformations at Cardiff
University: “Take the example of plant-based diets. There's not actually been many, if any, policies
that have encouraged people to make the shift towards plant-based diets, aside from a little bit of
health messaging. But there's been a big shift over the last decade towards plant-based diets.
Because people have chosen to eat differently and, by making that choice, helped shift the cultural
and social norms around plant-based diets.” Buying vegetarian products has indeed encouraged
manufacturers to create more of it and supermarkets to put it on their shelves, subsequently driving
further adoption and preference.

Where change matters most

Behavioural hotspots in terms of environmental impact include housing, water and energy
consumption, transport, food, waste and the consumption of goods. Among those, nutrition, housing,
and mobility are thought to amount to 75% of our total lifestyle carbon footprints. Let’s zoom in on
some of these categories:


Plant-based diets are considered as ones of the most impactful behaviours towards sustainability. It is
estimated that we could save between 29% and 70% of CO 2 emissions globally if we were reducing
our consumption of animal products. Fresh (excuse the pun) insights come on an ongoing basis,
related to both reducing meat consumption and increasing the adoption of plant-based diets. For
instance, a recent intervention by the Flemish Government focused on reducing meat consumption.
More specifically, it used the decoy effect to reduce the quantity of meat bought in supermarkets. By
simply offering an additional medium-size option for sausages, 18% less meat was bought in
supermarkets over the course of one month, although the number of sausages sold remained stable.


Our banking behaviours are also particularly important. The impact of our everyday deposit accounts
matters, as many banks currently use this money to loan to companies, including fossil fuel
companies. While we can rarely decide who our deposits will be lent to, our personal choice of a bank
will determine whether or not we participate in increasing carbon emissions globally. Amongst the
many pro-environmental behaviours, we can engage in, shifting to a sustainable bank can massively
increase our contribution to a better planet, as it tackles the climate crisis at the root.


Although many of our energy-related behaviours happen in the private sphere, protected from the
influence of social pressure, some others can be influenced by social norms. Take solar panels for
instance. These are not geographically distributed in a random way but appear as clusters. Installing
solar panels on your roof is likely to encourage your neighbours to do the same. And social influence
doesn’t stop there. Another study by Opower showed that simply informing people about the energy
consumption of their neighbours has helped save about 11 billion kilowatts of energy since 2007.
Since then, the use of social comparisons has been replicated by many energy utilities around the


Reducing plastic waste is also of prime importance, with some interesting interventions proving their
effectiveness. For instance, the Refill campaign aims to tackle plastic pollution at the source by
encouraging people to use reusable water bottles. Prior to the launch of the campaign, it appeared
that one of the barriers preventing people from using reusable bottles was the fact that asking for tap
water refills in restaurants and cafes was not perceived as being socially acceptable. Through the
Refill app, and stickers on front windows, the campaign showed people that refills were accepted by
many places around them, including cafes and chains selling plastic bottles, such as Starbucks or
Costa. An estimated one million plastic bottles have been saved since the start of the campaign.

Targeting the right groups

The good news is, moving towards a sustainable society does not necessarily require everyone to do
everything. Collectively adopting a small number of impactful environmental behaviours could already
bring about significant change. This said, it is extremely important that interventions designed using
behavioural science particularly target high-impact behaviours and the right socio-economic groups.
According to the World Inequality Database, in regions like the US or Europe, the richest 10% emits
six to seven times more CO2 emissions that the poorest 50%.

In relation to designing the right behavioural interventions, Polaris Koi from the University of Turku
takes the example of nudging and states: “It is of paramount importance that a nudge includes an
accurate and comprehensive analysis of the climate impacts; that we target the most effective
behaviours, rather than tinkering with something insignificant”, and adding “since harms from climate
change are unevenly distributed, disproportionately affecting the global poor, inefficiency would make
us complicit in those injustices and we need any intervention to be designed with that in mind.”

As a conclusion, new laws and technologies needs to be coupled with individual behaviour
change and acceptance in order to accelerate change. Governments and organisations have a
role to play in facilitating the adoption of sustainable behaviours, and that’s where behavioural
science comes into play. And citizens and consumers have the power to create ripple effects,
ultimately driving forward large-scale systemic changes towards a more climate-friendly