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How many hamburgers does it take to save the planet?

By Adam Corner on December 3, 2020

Fast food restaurant in the flood waters in Brisbane, Australia

With a group of leading international specialists, we’ve written a chapter on lifestyle changes and consumption emissions for the UNEP Emissions Gap 2020 report. Ahead of its release on 9 December, we reflect on the role of ‘knowledge’ in driving lifestyle changes, and the importance of creating the right social and structural conditions for behaviours to shift.

A recent paper published in the journal Climatic Change adds fuel to an old fire that continues to smoulder away: the role of ‘knowledge’ in driving behaviour change and public engagement on climate change.

The authors examine what they call ‘carbon numeracy’ by asking study participants in the US to rank the impact of different behavioural changes on emissions, and make estimates of the trade-offs between different actions (e.g. how many hamburgers equate to taking a flight, in terms of climate impact).

Perhaps unsurprisingly, people’s carbon numeracy was not especially strong – most participants were not able to consistently rank different actions correctly in terms of their carbon impact.  For instance, people taking part in the study judged the impact of recycling to be more significant for reducing emissions than reducing air travel or becoming vegetarian, and correctly answered tradeoff questions less than 20% of the time. 

From these results, the authors drew a stark conclusion:

While education is still necessary to correct larger misperceptions (especially regarding air travel and meat consumption) and to provide the public with a basic hierarchy of action efficacy, consumers who want to maintain a low carbon footprint would be best served by carbon labels in intuitive displays at the point of purchase, or by a price on carbon, because they are likely incapable of successfully balancing their own carbon footprints."

Old ways of campaigning?

The findings are interesting because they seem to support the ‘old’ way of thinking about campaigning on climate change, which prioritised the provision of information, and relied (often implicitly) on the so-called ‘deficit model’ of public engagement (whereby people would care more, or change their behaviours, when their ‘deficit’ of knowledge was addressed).

More contemporary approaches have emphasised the importance of values, worldviews, social norms and political ideology in determining engagement with climate change, and underpinning meaningful low-carbon lifestyle changes. 

The ‘nudge’ approach (also known as ‘Behavioural Insights’) offers a third route, with a more agnostic take on the role of knowledge (focusing instead on changes in the decision-making environment and avoiding questions of ‘persuasion’ altogether).

But the authors’ take on their findings represents an unusually reductive assessment of people’s agency and ability to make the ‘right choice’. Taking a few steps backwards, away from the study’s findings and looking to the wider context of public engagement, perhaps there is a different interpretation. 

Focus on the behaviours that matter

Campaigns have too often focused on ‘simple and painless’ behaviour changes, prioritising plastic bags and coffee cups over more impactful lifestyle shifts around diet and travel. As the authors of the new study note, this creates a strong ‘availability’ bias whereby people assume the actions they hear the most about are more impactful than they really are. So at a minimum, campaigns need to focus on the behaviours that matter – something we discuss in our chapter on lifestyle change in the soon-to-be-released UNEP Emissions Gap 2020 report.

The study found that the accuracy of people’s hamburger vs flight estimations was not driven by how much they cared about climate change (or their political orientation – a good proxy for climate concern in the US), but primarily on basic numeracy. 

Clearly knowledge does matter to some extent. Arguably, the pendulum has swung so far away from the deficit model for some practitioners that there’s a risk that knowledge is discounted altogether. But what kind of knowledge matters? 

Being able to roughly rank the impact of different actions is the kind of knowledge that has practical value, and seems a valid target for campaigner energy. But calculating hamburger-to-flight ratios is something that no one other than climate geeks would need to do.

Create the right conditions for social transformations

Carbon labelling is a long overdue development that would certainly help people to make the best possible decisions. But as other social transformations make clear, this approach is necessary but not sufficient for changing behaviours. Over the last decade, levels of smoking have reduced rapidly in many countries around the world – this has been driven not only by labelling (health warnings) but also by shifting social norms and structural changes (laws and regulations). 

Campaigns across policy and advocacy must create the conditions under which it’s clearer (by focusing on the right kinds of behaviour), socially desirable (by promoting positive social norms) and perceived as fair (by mirroring any behavioural changes with structural shifts) to make the ‘right decision’.

That way, nobody needs to calculate hamburger-to-flight ratios to do the right thing. 

By Dr Adam Corner

After studying the psychology of how people reason about new evidence, and why they do or don’t change their beliefs, Adam worked in the Understanding Risk research group at Cardiff University, researching public attitudes towards climate change. Adam joined Climate Outreach as a Researcher when the organisation was still young, helping to grow the Research team and build long standing relationships with academic partners, including the CAST centre (Climate Change & Social Transformations).

As the organisation has grown, Adam’s role as Programmes & Research Director now includes working with academic partners, campaign strategists and funders to ensure that Climate Outreach delivers on its mission of building the social mandate around climate change.  An accomplished and widely-published author, Adam wrote Talking Climate: From Research to Practice in Public Engagement, with Jamie Clarke, and his research and writing has appeared in academic journals, reports and briefings, and international media commentary. Adam also writes about music – including the increasing connections between music and climate change – for UK media, and can occasionally be found lurking behind the decks at pubs and parties in Bristol.

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