By Nick Chater, Theresa Marteau and Emma Garnett

Many major economies, including the US, EU, and UK, have committed to net zero greenhouse gas emissions by 2050 to limit climate change. Immediate action is needed to hit this target and to minimise cumulative emissions. Current commitments are, however, unmatched by action.

The UK Government, for example, though among the first to set a legally binding target of net zero by 2050, has so far fully implemented only 11 of 92 policy recommendations from its climate change committee and is not on track to meet net zero or the medium term carbon budgets.

The latest International Panel on Climate Change report estimates that if global emissions are halved by 2030 and net zero is reached by 2050, the current rise in temperatures could be halted and possibly reversed. The 26th UN climate change conference (COP26) offers a precious opportunity to get back on track.

Behaviour change by individuals, commercial entities, and policymakers is critical to achieving net zero in all domains. Here we focus on behaviour concerning diet and land travel, given their importance for both achieving net zero and improving population health, but the approaches we outline are also applicable to other behaviours.

Diet and land travel contribute an estimated 26 per cent and 12 per cent of greenhouse gas emissions, respectively. Cutting these emissions would also benefit health by reducing air pollution - now the greatest external threat to human health - increasing physical activity, and healthier diets, thereby tackling major risk factors for non-communicable disease globally.

Changes in demand are going to be critical to achieving net zero, alongside technological innovation. Dietary change is likely to deliver far greater environmental benefits than can be achieved by food producers. Similarly, for land travel, reducing demand for high emission vehicles would deliver important reductions: sport utility vehicles were responsible for the second largest increase (after power) of global carbon emissions between 2010 and 2018. Shifting demand equitably, however, requires structural interventions to drive behaviour change by whole populations.

We consider the behaviour of three groups central to achieving net zero by 2050: the public (both as citizens and consumers), policymakers, and private sector leaders.

Changing behaviour of the public at scale

Adopting the largely plant-based diet and taking most journeys using a combination of walking, cycling, and public transport would substantially reduce greenhouse gas emissions and improve our health.

Changing behaviour at scale is difficult, especially when the behaviours to be changed are cued, reinforced, and maintained by the physical, economic, and social environments in which they occur—as is the case for diet and land travel. Multiple interventions will be required in all these contexts to achieve the size of change needed for net zero.

People’s knowledge of which behaviours generate the most greenhouse gases is generally poor. For example, only 20 per cent of people in a large international survey identified eating a plant-based diet or not owning a car as among the most effective actions. Providing information to correct such misperceptions could, importantly, increase public support for government policies for net zero, but such information is unlikely to change these behaviours.

Information can be extremely effective at changing behaviour when it concerns serious, immediate threats to life. A sign warning of shark infested waters stops most people from swimming. But when the information concerns less immediate threats it often has minimal effects on behaviour. For example, information campaigns on the health benefits of consuming more fruit and vegetables successfully increased awareness but did not alter consumption. Similarly, conservation scientists were not found to have lower environmental footprints than other professionals despite their greater environmental knowledge.

The interventions with the most potential to change routine or habitual behaviour at scale target whole populations and involve changes to the systems shaping and maintaining the behaviour. They can be described as structural, designed to create environments that readily enable sustainable behaviours and make unsustainable behaviours more difficult.

These interventions also place lower demands on the cognitive, social, and material resources of individuals than those based on providing advice and guidance, thereby having greater potential to achieve change equitably. For example, increasing the proportion of vegetarian meal choices in UK cafeterias from one in four to two in four increased their selection from 24 per cent to 39 per cent. Construction of an urban greenway in the US increased journeys by bike 250% among those living closest.

How these sort of interventions can best be implemented partly depends on whether they concern public or private sector settings. For public settings, changing procurement standards to include only sustainable healthy options would be a good start. Portugal and Scotland have regulations to increase the availability of sustainable and healthier foods in public sector settings. In private sector settings regulation is needed since voluntary agreements to improve public health, mainly comprising pledges such as providing information, have been largely ineffective.

Interventions that decrease the affordability of unhealthy unsustainable options and increase the affordability of healthier sustainable options would also help change public behaviour, particularly in combination. These include removing subsidies on high emission products such as livestock and fossil fuels and using taxes and other price-based mechanisms to reflect the emissions associated with different products and activities.

Interventions need to be fair and equitable as well as effective to gain public support, which in turn increases their political acceptability. Globally, the wealthiest 10% consume more than 20 times more energy than the poorest 10 per cent. Pricing carbon on energy and land use at levels that could achieve net zero by 2050 - perhaps reaching more than $560 (£410; €480) per tonne of CO2 equivalent - would increase the price of transport and food, disproportionately affecting the poorest and those living in rural areas. Any such policy would need to be part of a package that, at a minimum, shields poorer households but better, is part of broader sets of policies that tackle poverty and inequality both within and between nations.

Policymakers and private sector leaders

Changing the behaviour of the public at scale requires substantial changes to the behaviour of policy makers, private sector leaders, and citizens.

Behaviours within these three groups that create barriers to implementing effective interventions include inadequate political leadership and governance to enact policies, strong opposition by powerful commercial interests, and lack of public demand for policy action. Countering these behaviours and enabling positive ones will be crucial to achieving net zero.

Public support for change is lower when it affects current behaviour and trust in governments is low. Support can be increased by ensuring policies are perceived as both fair and effective. Support can also increase after an intervention is implemented, reflecting the bidirectional relation between behaviour and attitudes. For example, public support for congestion pricing increased after its introduction in many cities, reflecting both changes in attitudes and acceptance of the status quo.

Private sector organisations must also make substantial changes to align with net zero, from agricultural and food production, the extractive industries, manufacturing, transport, and the energy sector. As in any transition, there will be winners and losers. The focus for government should be to encourage fast adapting organisations—new and old—that will speed up the transition to net zero.

A major threat comes from some private sector organisations with most to lose. This includes fossil fuel companies that have engaged in activities to deny or cast doubt on human induced climate change and the need for a low carbon transition.

In 2021, an Exxon lobbyist was secretly recorded by Greenpeace stating that the oil company worked with “shadow groups” to undermine climate science and that the company’s key climate commitments were disingenuous. Large agribusinesses and parts of the food industry also engage in similar activities to prevent or delay effective policies for dietary change. An analysis of documents from the meat industry found that they framed the health and environmental effects of red and processed meats to minimise perceptions of harm and to encourage continued consumption. Of particular concern, is the influence of vested corporate interests on the activities of the World Health Organization and UN bodies.

Actions to protect policies for net zero from corporate interference:

  • Exclude corporations from setting and implementing policies, as exists for the tobacco industry under article 5.3 of the Framework Convention on Tobacco Control.
  • Prevent and manage conflicts of interest in policymaking by, for example, training policymakers, developing an index assessing impacts of individual corporate organisations, and setting up independent panels to advise on corporate engagement in policymaking.
  • Establish statutory registers of corporations lobbying governments to allow public scrutiny of the nature and scale of their activities, including all donations.
  • Use regulations, frameworks, and criminal law to prevent corporations from misleading the public and causing environmental and other harms, including destroying ecosystems.

Towards a fair transitioned future

Complex coordinated behaviour can be mobilised by a shared, positive narrative, reflecting collective goals, alongside a clear vision, making vivid the many benefits of a net zero world, with a roadmap and timelines. The development of such a vision—both global and regional—is a priority and requires co-creation by citizens, governments, and industries, informed by scientific expertise and protected from corporate interference.

Read the original article at the The British Medical Journal. 

Nick Chater is Professor of Behavioural Science and teaches Behavioural Science for Managers on the Executive MBA and Executive MBA (London). He also lectures on Judgement and Decision Making on the MSc Finance and Principles of Cognition on the suite of MSc Business courses.

Professor Dame Theresa Marteau is Director of the Behaviour and Health Research Unit at the University of Cambridge.

Emma Garnett is Prince of Wales Junior Research Fellow at the Cambridge Institute for Sustainability Leadership at the University of Cambridge.

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