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• Research shows swapping beef burgers for vegan options could slash environmental impact of barbecues.
• Scientists from the University of ºù«Ӱҵ’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.

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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 ºù«Ӱҵ’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 (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 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 ºù«Ӱҵ, Lancaster, Manchester and others.

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

"We have come up with some great activities and games to get this message across to the public. I am really excited to be able to share with over 15,000 visitors to the Royal Society the excellent research that is happening in the University of ºù«Ӱҵ’s Institute for Sustainable Food, the broader N8 Agrifood programme, and the STFC Food Network+."

The Institute for Sustainable Food at the University of ºù«Ӱҵ 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 ºù«Ӱҵ

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.

"Did you know for example that the production of a 100g medium-sized beef burger releases enough greenhouses gases to fill more than 60 balloons?" said Professor Bridle. 

"That’s equivalent to driving more than six miles in a car. By switching to chicken you could reduce that to around 15 balloons, or about one and a half miles in a car.

"Did you know that the production of a portion of strawberries would release enough greenhouse gases to fill about five balloons, but this would rise to about 10 balloons on adding two tablespoons of cream, or to over 20 balloons if flown in out of season? And the manufacture of each bottle of beer causes emissions equivalent to about 8 balloons full of greenhouse gases.

"By making a few small changes to our diets such as swapping beef for chicken or a vegetarian alternative, a fizzy drink to tap water, a cheese sandwich to a peanut butter sandwich, or a fry-up breakfast to porridge we can make a significant impact."

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.

Carbon dioxide equivalent (CO₂e)

*Typical barbecue: 5.8kg CO2e per person	*Lower emissions barbecue: 3.2kg CO2e per person	*Vegan barbecue: 2kg CO2e per person
¼ of 500g bag of charcoal	¼ of 500g bag of charcoal	¼ of 500g bag of charcoal
Two bread rolls	Two bread rolls	Two bread rolls
Two tbsp butter	Two tbsp butter	Two tbsp vegetable spread
Two burgers (200g)	Two small chicken breasts (200g)	Two large veggie sausages (200g)
Two slices of cheese	Two slices of cheese	Half an onion
One medium tomato (in season)	One medium tomato (in season)	One medium tomato (in season)
Two tbsp tomato ketchup	Two tbsp tomato ketchup	Two tbsp tomato ketchup
Handful of strawberries	Handful of strawberries	Handful of strawberries
Two tbsp of cream	Two tbsp of cream	One tsp sugar

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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:   
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.