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Changing behaviour for net zero 2050

BMJ 2021; 375 doi: (Published 07 October 2021) Cite this as: BMJ 2021;375:n2293

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  1. Theresa M Marteau, professor1,
  2. Nick Chater, professor2,
  3. Emma E Garnett, researcher3
  1. 1Department of Public Health and Primary Care, Behaviour and Health Research Unit, University of Cambridge, UK
  2. 2Warwick Business School, University of Warwick, UK
  3. 3Cambridge Institute for Sustainability Leadership, University of Cambridge UK
  1. Correspondence to: T M Marteau tm388{at}

Theresa Marteau and colleagues argue for rapid, radical changes to the infrastructure and pricing systems that currently support unhealthy unsustainable behaviour

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.1 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.2

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.3 The 26th UN climate change conference (COP26) in November 2021 offers a precious opportunity to get back on track.

Behaviour change by individuals, commercial entities, and policy makers 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%4 and 12% of greenhouse gas emissions, respectively.1 Cutting these emissions would also benefit health by reducing air pollution—now the greatest external threat to human health5—increasing physical activity, and healthier diets, thereby tackling major risk factors for non-communicable disease globally.678

Changes in demand are going to be critical to achieving net zero, alongside technological innovation.9 Dietary change is likely to deliver far …

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