Food & drink are our most fundamental physiological needs. The foundation of all animals is the gut: all the other organs evolved to support its functioning.
For a resting adult human, metabolic rates are assessed to be between 1200 and 3000 calories per day. Active metabolic rates can, of course, be much higher. We all need to eat!
But what we eat and how it gets into our mouths, has a great impact on the resources we consume and the carbon pollution that we cause getting our daily calorie intake…and in some cases more.
Food production is estimated to account for 26% of overall greenhouse gas emissions but individual dietary impacts are highly sensitive to what you eat, how much you eat, where it was grown, how it got to you and how it was produced.
What you eat
The BBC carbon footprint calculator works on the basis of the kg CO2e for a standard portion. I’ve equalised the frequency of consumption to give a comparison. Obviously, if you eat more of one thing than the other the columns rise and fall.
Source: BBC
The clear breakpoint between animal products and plants is clear however. Each cow, sheep or goat, after all, is a walking methane refinery and methane is a far more damaging greenhouse gas than carbon dioxide.
So, looking at the picture in the large we get this…
But, according to recent research on word use in contemporary English, when we talk about eating we talk about meat…a lot![i]
In this diagram, distance from the headword (the black dot) reflects how closely relate each coloured dot is to the theme. The size of the dot relates to the frequency of use per million words. On this basis English speakers, culturally, refer to ‘meat’ far more than vegetables and fruit.
But we need our 3000 calories per day don’t we. And we need protein…that comes from meat, right? Not necessarily.
The figure below illustrated the greenhouse gas emissions per unit of protein (100 grammes) and kilocalories.
Food and Climate Change: Healthy diets for a healthier planet | United Nations
Once again, vegetables have a far lower effect on climate than animal products in these terms. Sugar, by the way produces 142 kilogramme of CO2e for every 1000 kilocalories…putting it right off the scale. It takes a lot of energy to crush and boil sugar though brown cane sugar has a lower impact than white beet sugar.
Where it was grown, how it got to you
The food supply chain is global and, especially in the global North, delivers a vast array of flavours and choices to individual consumers. Food-miles has become an indicator, though not necessarily a useful one, of the carbon footprint of foodstuffs.
But it is not only the geographical distance but the means of transport and the needs of preservation that drives actual footprint. Air freight (for high value perishables) is more carbon-intensive than ship-based refrigeration, road or rail transport or the simple steerage-shipment of dry goods.
And provenance is not the only factor.
DEFRA estimates that moving food is responsible for 25 per cent of all miles covered by heavy goods traffic in the UK. Transporting food within, to and around the UK produces 19 million tonnes of CO2e annually – equivalent to around 5.5 million typical cars. I know from family anecdote that prawns landed in the North East of Scotland is sometimes shipped to England for processing before being freighted back to the Moray coast.
What we eat- production – still massively out-weighs where it comes from, however (7.1 Gigatonnes compared to 3 Gigatonnes) and there are sometimes sound reasons for buying internationally rather than local in terms of how food is produced e.g. studies have found that New Zealand lamb has a lower overall foot print than British lamb in the UK due to the other inputs used in the UK production process. Similarly, in terms of climate justice, sustaining the economies of less developed nations might have a better outcome in terms of mitigating climate injustice than depriving these producers of a market.
How it was produced
The energy and chemicals inputs associated with production also has an impact on the carbon intensity of a portion of food as well as on other polluting and destabilising effects such as loss of biodiversity, water pollution and loss of soil fertility.
Fertiliser inputs ultimately derive from energy inputs – and general fossil fuel inputs. Lot feeding animals has far greater impact than grass fed animal husbandry. But a recent study concluded that “better management of grass-fed livestock, while worthwhile in and of itself, does not offer a significant solution to climate change as only under very specific conditions can they help sequester carbon. This sequestering of carbon is even then small, time-limited, reversible and substantially outweighed by the greenhouse gas emissions these grazing animals generate. The report concludes that although there can be other benefits to grazing livestock – solving climate change isn’t one of them.”
Mining for Food
Agriculture has shaped many of the world’s contemporary landscapes and the energy and production intensity of industrial agriculture has the many negative effects outlined above. But there is another strand to food production: the industrialisation of hunter-gatherer lifestyles that characterises the contemporary fishing industry.
Overfishing has repeatedly resulted in collapse of species, resulting in some cases in long moratoriums which in turn drive fishers to exploit new, often more distant species.
Fishing is having a dramatically negative effect on the biodiversity of marine life already under pressure from warming and acidifying oceans.
In fisher communities in Scotland, many audience members raised concerns about both the impact of fishing AND the loss of culture and lifeways that a ban on fishing will cause. Quotas and the dumping of by-catch, whether for commercial or policy reasons is massively wasteful whilst bottom trawling and dredging for specific species devastates ecosystems as surely as open cast mining but, conveniently, at the bottom of the sea and some distance from the shore.
How much you throw away
In the UK we ‘waste’ ten million tonnes of perfectly good food, discarding it or allowing it to rot uneaten. 70% of this – 6.6 million tonnes – is food we have already purchased but do not eat. That’s 98 kg per person (15 stone per person in old money).
And these figures relate to ‘post farm gate’ waste.
According to Agrimetrics “Huge amounts of edible food are lost even before it reaches the farm gate. Estimates from the Food and Agriculture Organisation of the United Nations suggest that globally it could be between 500-850m tonnes, equivalent to approximately 10-15% of the world’s food production. Much edible food is lost even before it reaches the farm gate, but it is difficult to address this problem as the amount and type of waste in primary production is not currently measured or assessed.
The volumes in the UK could be immense, but this is difficult to measure. One fenland producer estimates 3 million iceberg lettuce heads are produced surplus to requirements each year, this is partially due to weather conditions, but also as a result of specifications over the desirable ‘head size’.”[ii]
A recent WWF report quantified pre-farm gate waste in the UK.[iii]
Looking at these figures in a different way, the amount of edible food wasted before it leaves the farm is 9.2 million tonne. The levels of waste vary by food-type however with seafood and fruit and vegetables wasting around 50% of their total production before the farmgate or the quayside.
Adding pre- and post-farm-gate estimates of wastage, the UK Population and their food suppliers waste around 18 million tonnes of food every year, every kg of which has its own carbon footprint.
Conclusion
The contemporary human food chain, as the affluent experience it in the global North, offers a vast range of choice and nutritious options are artificially low prices subsidised by polluting fossil fuel inputs.
Carbon pollution and waste both vary by food type. Categories with relatively low carbon footprints may also have very high wastage rates.
And yet, due to in-country inequality, many in the North still struggle to afford a nutritious diet – resorting to food banks to fill the deficit – whilst others over-eat, with attendant loss of well-being through obesity and diabetes.
The food choices we make, individually and collectively have a huge influence on out ability to limit global warming to tolerable levels and the address wider aspects of community resilience and climate justice.
What we eat, how we obtain it and how we share it are therefore important aspects of climate literacy. We have to eat: we need, for al of our sakes, to learn to eat well.
[i] Brezina, V., & Gablasova, D. (2023). A Frequency Dictionary of British English: Core Vocabulary and Exercises for Learners. Taylor & Francis