Meat-free Fridays saving the world? 

In 2011, the Catholic bishops of England and Wales called on congregations to return to foregoing meat on Fridays. Only around a quarter of Catholics changed their dietary habits – yet this has still saved over 55 000 tonnes of carbon a year, according to a new study led by the University of Cambridge.

Researchers say that, in terms of CO₂ emissions, this is equivalent to 82 000 fewer people taking a return trip from London to New York over the course of a year.

The current Catholic leader, Pope Francis, has called for “radical” responses to climate change. The researchers argue that if the Pope reinstated meatless Fridays across the global church, it could mitigate millions of tonnes of greenhouse gases annually.

For example, they say that if Catholic bishops in the United States alone issued an “obligation” to resist meat on the last day of the working week, environmental benefits would likely be 20 times larger than in the UK.

“The Catholic Church is very well placed to help mitigate climate change, with more than one billion followers around the world,” says lead author Professor Shaun Larcom from Cambridge’s Department of Land Economy.

“Pope Francis has already highlighted the moral imperative for action on the climate emergency, and the important role of civil society in achieving sustainability through lifestyle change.

“Meat agriculture is one of the major drivers of greenhouse gas emissions. If the Pope was to reinstate the obligation for meatless Fridays to all Catholics globally, it could be a major source of low-cost emissions reductions, even if only a minority of Catholics choose to comply, as we find in our case study,” Larcom adds.

An average high-protein non-meat diet – including foods such as fish (which is classed separately to land-based meat sources) and cheese – contributes just a third of the greenhouse gas emissions per kilogram compared to the average meat eater, the research team highlights.

“Our results highlight how a change in diet among a group of people, even if they are a minority in society, can have very large consumption and sustainability implications,” says co-author Dr Po-Wen She, a fellow of Cambridge’s Department of Land Economy.

Co-author Dr Luca Panzone from Newcastle University adds: “While our study looked at a change in practice among Catholics, many religions have dietary proscriptions that are likely to have large natural resource impacts. Other religious leaders could also drive changes in behaviour to further encourage sustainability and mitigate climate change.”