Typical summer BBQ releases more greenhouse gas emissions than 80-mile car journey

• Research shows swapping beef burgers for vegan options could slash environmental impact of barbecues.
• Scientists from the University of Sheffield’s Institute for Sustainable Food part of team highlighting how diet contributes to climate breakdown with Royal Society exhibit.
• Experts to use balloons to represent the volume of greenhouse gases emitted by barbecues.

A typical summer barbecue* for four people releases more greenhouse gases into the atmosphere than an 80 mile car journey, according to a group of scientists studying the impact of food choices on the environment.

The scientists, from the University of Sheffield’s Institute for Sustainable Food and across the UK, have come together to shine a spotlight on how consumer decisions on diet, as well as new technologies, could help reduce global heating. Their work is being showcased this week at the Royal Society Summer Science Exhibition (1–7 July 2019) in London. 

The Take a Bite out of Climate Change exhibit will take visitors on a journey from ’farm to flush’ to explore greenhouse gas emissions (GHGE) at all stages of food production, processing, supply and consumption. It follows a commitment by Prime Minister Theresa May that the UK government will cut GHGE to net zero by 2050. 

The team brings together academics from food resilience programme N8 Agrifood and innovative technology solutions from the Science and Technology Facilities Council (STFC) Food Network+.

The exhibit will feature innovation in food production by the National Centre of Food Manufacturing at the University of Lincoln, Entocycle and LettUs Grow, with underpinning research from the Universities of Sheffield, Lancaster, Manchester and others.

Christian Reynolds from the Institute for Sustainable Food – a Knowledge Exchange Research Fellow in the University of Sheffield’s Department of Geography – said: "Changing diet is one of the most significant ways that people can reduce their impact on the environment. 

The Institute for Sustainable Food at the University of Sheffield brings together multidisciplinary expertise and world-class research facilities to help achieve food security and protect the natural resources we all depend on.

Lead scientist, Professor Sarah Bridle, from the University of Manchester, said: "Food contributes over 20 per cent of all greenhouse gas emissions. As the barbecue season gets underway, people might like some food for thought about the impact of their choices on the environment"

Changing diet is one of the most significant ways that people can reduce their impact on the environment.

Christian Reynolds, Institute for Sustainable Food at the University of Sheffield

The team wanted to create a visual representation for visitors to their stand, so used helium-filled balloons to match the equivalent volume of CO₂ that goes into the atmosphere in the production of different foods.

The group of scientists has calculated that a typical barbecue* would equate to the equivalent of over 200 balloons of carbon dioxide per person, equivalent to each person driving over 20 miles, whereas a lower emissions barbecue* where beef burgers were replaced with chicken – would be approximately 130 balloons of greenhouse gases per person.

A vegan barbecue*, where meat was replaced with vegan sausages, cheese was swapped for onion, butter was swapped with vegetable spread and cream was switched to sugar – would reduce the emissions again. This would emit the equivalent of about 80 balloons of carbon dioxide for the whole meal – which corresponds to driving about eight miles per person, and is less than half of the typical barbeque emissions.

The Take a Bite out of Climate Change exhibit aims to raise awareness of the innovative ways that cutting-edge science is transforming food production, including vertical and precision farming techniques, tools to measure soil emissions and improvements in supply chain efficiency and resilience using blockchain, Internet of Things and cryogenics.

The scientists also hope fascinating data about consumer food decision making gathered from a project on people-powered online research platform Zooniverse, will encourage visitors to make behaviour change pledges.

Dr Helen Downie, from the University of Manchester, who is co-leading the project has called on consumers to demand the latest information on environmental impacts from food producers, to enable them to make fully informed choices and motivate food producers and retailers to lower their emissions.

Visitors to the exhibition will be able to test their knowledge by playing a computer game to guess the greenhouse gas footprint of different foods and play a game to learn about how food production can be improved to reduce emissions on farms.

Notes

1. Please seek professional advice before making significant changes to your diet.
2. Greenhouse gas emissions from food production can vary significantly depending on the production method and country of origin.
3. We have assumed a portion size of 80g for the strawberries and a bottle size of 25cl for the beer.
4. Cars vary in their emissions per mile. For these calculations we have assumed 154g CO₂e/km but the latest most efficient fossil fuelled models can be as low as 80g CO₂e/km.
5. We have assumed a density of carbon dioxide of 1.98 kg per cubic meter, which corresponds to standard temperature and pressure. 
6. We have assumed balloons are spheres of 29 centimetre diameter.
7. The Summer Science Exhibition is located in the Royal Society, 6-9 Carlton House Terrace, London, SW1Y 5 AG and takes place from Monday 1 July to Sunday 7 July 2019. The event is free and open to the public. Every year 22 research groups from across the UK are chosen to exhibit
8. Pre-recorded footage of the exhibits is available from the Royal Society on request
9. More information can be found at: www.royalsociety.org/summer-science  
10. The Royal Society has held a Summer Science Exhibition to showcase the best of UK science since its early days, when Fellows of the Society were invited to the President’s home to view instruments and specimens from the latest research. Presidents have hosted displays and discussions of the latest scientific research since the early 19th century. Visitors in 1896 had their hands X-rayed while those in 1910 could view novel pictures of Halley’s Comet. New technology such as Thomas Edison’s incandescent lamps were exhibited in 1889 while Captain Scott’s Terra Nova expedition to Antarctica 1914 showcased natural history specimens.