It's a Gas – Issue 23

It’s a Gas: Paul Freestone breaks down the science behind greenhouse gas emissions.


At the end of last year, BBC Radio 4’s Inside Science asked if going vegan can actually reduce your dietary carbon footprint by up to 50 per cent? Peter Scarborough, of Oxford University, has done some of the most authoritative research on this subject and said: “Yes that’s absolutely right, it comes from the study we did in 2014. We looked at the carbon emissions associated with the diets of meat eaters, vegans, vegetarians, and also people who eat fish but not meat (pescatarians) and compared the carbon emissions of each group, and did find that vegans have half the carbon footprint of meat eaters.”


He continued: “Vegetarians and fish eaters have very similar levels of emissions, about 35 per cent less than meat eaters. Levels of dietary carbon emissions are strongly related to the amount of meat consumed. If you move from a high meat intake to a lower amount, you can reduce emissions by about 35 per cent.


“So if you want to make a difference then cut down the amount of meat, and you will make an impact, but you don’t have to go all the way to vegan. However, if you go from being a meat eater to vegan, you will be taking a ton of CO2 out of the atmosphere. That’s about equal to an economy return flight from London to New York.”


The presenter (Adam Rutherford) sounded slightly incredulous but said: “That’s an incredibly persuasive argument isn’t it?” So why does eating meat cause such a significantly higher carbon footprint per person? Peter Scarborough says: “There are two main issues. Direct emissions from animals as cows and sheep produce methane, which is a very potent greenhouse gas, about 25 times more potent than CO2. But the main problem is because it’s a very inefficient way of producing calories. Almost all the animals we consume are fed cereals and crops that could be eaten directly by humans. Changing your diet is a very empowering thing to do, and can have a very significant impact on global greenhouse gas emissions.”


Unfortunately this vital information is less well known that it should be.


It would be astonishing if The Daily Mail ever published a front page headline that screamed: ‘Eat Less Meat to Save the World’. Also, numerous environmentalists and conservationists seem very reluctant to advocate a switch to a vegetarian or vegan diet. Pressure groups such as Greenpeace and Friends of the Earth [FOE] offer distinctly mixed messages. FOE promotes the flexitarian diet (mainly plant–based foods but includes small amounts of meat, fish and dairy) and says: “Not all meat and dairy production is environmentally damaging.” The obvious response to this statement is that the overwhelming impact of global meat and dairy production is absolutely devastating. The UN’s seminal Livestock’s Long Shadow (2006) report concluded that global livestock are responsible for more greenhouse emissions (estimated at 18 per cent) than all the world’s transport systems put together (estimated at 13.5 per cent). These statistics have been very influential, and unsurprisingly have been disputed by the meat industry ever since.


The subsequent edition of Inside Science included listeners who challenged Peter Scarborough’s 50 per cent figure, and argued that it only applied to grain fed animals. Also, that it was ‘environmentally OK to eat meat as long as the animal was grass fed’. Dr Tara Garnett, of the Food Climate Research Network at Oxford University, said: “Livestock as a whole are approximately responsible for 15 per cent of all greenhouse emissions, and ruminants contribute about 80 per cent of that total. (Ruminants use a four stage stomach to digest grass via a fermenting process). Firstly, the issue of methane and nitrous oxide. Secondly, carbon dioxide that arises from livestock induced land change. Every time forest is cleared to rear animals that contributes to the total. Animals reared on grass grow more slowly, and they emit more methane per unit of weight gain or per unit of milk produced. Because methane is so potent, the overall greenhouse gas footprint (of pasture fed cattle) is going to be higher than animals in intensive systems. If you just reared animals on grasslands and rough agricultural by–products, you would get just 26g of meat of all kinds per person, per day. With ruminant meat it’s just 19g (the size of a tiny burger). For milk it’s 138g per day, roughly equal to the amount in four cups of tea.”


Therefore, it’s very useful to have this 15 per cent figure for global emissions, as it’s probably a slightly conservative estimate. Also, it underlines the uncomfortable fact that grass fed livestock can be worse for the environment than the intensively reared counterpart.


Incidentally, at the excellent ‘Visioning Food After Brexit’ event in Oxford (1/11/16) Duncan Williamson from the World Wildlife Fund presented his six main recommendations for a better food future. Two of these were ‘eat more plants’ and ‘moderate your meat consumption, both red and white’. Also, there was a clear agreement from the other three panelists (Colin Tudge, Julian Cottee, and Peter Scarborough) and the chairman (Paul Jepson) that meat is a major problem. However, Duncan mentioned that there are at least 12 different UK government departments that deal with food, but there is ‘no joined up thinking between any of them’. He also said that ‘food is complicated, and there is no simple solution’. Nonetheless, he suggested that a dedicated ‘Ministry For Food’ would be a good starting point. Unfortunately, this seems highly unlikely. C4’s Dispatches (31/10/16) exposed how the original document Childhood Obesity: A Plan For Action (prepared under David Cameron’s premiership) has been decimated by Theresa May.


All the progressive proposals have been removed, I believe this highlights the nefarious influence of food industry lobbyists. All major world leaders have to grasp at least some of the indisputable facts about meat and dairy production. Firstly, it’s totally unsustainable and hopelessly inefficient. Secondly, the environmental impact is catastrophic. And yet we now have Donald Trump elected as president of the USA, and he has clearly declared that he doesn’t believe in manmade climate change.