As we all seek to reduce the size of our carbon footprint, changing the way we eat has become a focal point of discussions around reducing greenhouse gas emissions, water consumption and leading a more environmentally-friendly lifestyle. In January 2019, 250,000 people signed up to ‘Veganuary’ – a movement which challenges participants to go vegan for the month – and according to the Veganuary website, 47% of participants reported that they intended to continue following a vegan diet. This January, Veganuary aims to attract 350,000 participants in the month-long challenge to go vegan. Given that it takes up to 20 times as much water to produce 1 kcal of beef as it does for 1 kcal of tomatoes, and with organic farming being shown to produce less greenhouse gas (GHG) emissions per commodity, changing to an organic plant-based diet may seem like the obvious choice when it comes to reducing our dietary carbon footprint.
However, research has shown that what we perceive as ‘greener’ choices may actually be having an unintended impact – whether it’s the amount of water consumed to grow our fruit and vegetables, or the carbon emissions created by transporting and storing fresh produce.
So, if we want to change our diet to be greener – how can we make sure we do so effectively?
Increased organic production could hinder, rather than help when it comes to reducing the farming industry’s carbon emissions
While organic farming may produce lower GHGs per commodity, it also produces less food energy output per hectare. Research by Cranfield published in October 2019 has suggested that moving to 100% organic farming in England and Wales could actually reduce our food yield by up to 40%. Therefore, while direct GHG emissions are reduced by farming organically, the increased import of food to compensate for the shortfall and the increased amount of land used overseas to produce our food could mean the net emissions would be greater, if our national diet remained the same. A move to 100% organic farming in England and Wales could potentially increase net emissions by 21%.
The research also highlights the limits of the higher carbon sequestration rates - the amount of carbon that is captured and stored in soil - associated with organic farming in offsetting the increased emissions. While the amount of carbon captured by the soil is higher under organic farming, the soil reaches a steady state after a decade or two. Therefore, increased sequestration is only able to offset a small part of the increased emissions that could occur under a 100% organic farming method.
Professor Guy Kirk, Professor of Soil Systems at Cranfield, commented that the “undoubted local environmental benefits” associated with organic farming (such as reduced pesticide exposure and improved biodiversity) need to be set against the requirement for greater production of food overseas.
Reducing the environmental footprint of our diet isn’t as simple as just opting for more fruit and vegetables
When it comes to changing what we eat to reduce the environmental burden of food production, the focus is often on substituting meat for plant-based foods. Given the evidence, both in terms of the impact of rearing animals and the methane the animals themselves produce, switching to a plant-based diet may seem like an obvious, and straight forward, change to make.
However, recent research carried out by Professor Tim Hess and colleagues has shown that it’s not just what we eat that matters, but also where it’s produced, how it’s stored/transported and when we are consuming it: “The processes required to produce food create burdens on the environment… the environmental impacts of the production and distribution of individual foods vary considerably, depending on the life cycle of the product; the geographical location of production and consumption; and the degree of post-harvest processing… The contribution of an individual’s diet to their overall environmental footprint depends on what they eat as well as how much they eat and where the food was produced.”
Studies have shown that a vegetarian diet consumes 35-50% less water than a “typical” reference diet – but the effectiveness of this change depends on what meat-based products are substituted for.
The first environmental impact to consider is the amount of water that is used to produce the food that we eat. Much of the water consumed by food production is “blue water” – water that is withdrawn from rivers, reservoirs and groundwater. Around 80% of the world’s population is suffering serious threats to water security and 70% of water withdrawals are for agriculture. 76% of the blue water used to grow fruit and vegetables for the UK is withdrawn overseas, often from water scarce countries. If a reduction in the consumption of meat-based commodities is replaced by an increase in the consumption of irrigated fruit and vegetables, imported from countries such as Spain which already have a high level of water stress, we may inadvertently be solving one problem while causing another.
Furthermore, it’s not as simple as meat vs plants – a study into the impact of food choices within a food group, in this instance starchy carbohydrates, found that choices between seemingly similar foods can also have an impact on the overall environmental burden. [1] The study compared the impact on GHG emissions and water usage between pasta, rice and potatoes. 50% of all basmati rice sold in the UK is grown in specific regions of India and Pakistan – with high levels of methane emitted from the paddy fields, high transportation distances and high water usage. Rice was found to have a much greater impact on GHG emissions (0.17k CO2e, 160l H2Oeq) compared to potatoes (0.05kg CO2e, 0.6l H2Oeq). The dietary trend in the UK of favouring rice over potatoes has increased the burden on global water resources, and relocates the impact of this choice from the UK to other areas of the world. The study exemplifies that it’s not just a case of favouring one food group over another, but considering the impact of our choices within a food group and having an awareness of our food’s life cycle in order to make the greenest choice.
Put simply, there’s a danger that by simply opting for fruit and vegetables over meat without considering how we do so – knowing how our plant-based foods were produced, where they were produced and how they are transported to our plates – may just relocate the environmental burden.
So how can we go green, greenly?
To effectively reap the environmental benefits of making more plant-based food choices, we need to consider the journey from farm to fork
When we’re trying to make greener choices in our diet, it comes down to knowing where our food comes from, eating seasonally and making sure we don’t waste food unnecessarily.
According to an article published by Terrapass, you can reduce the carbon footprint of the fruit and vegetables you eat by up to 7% by eating locally grown produce – reducing the number of miles your food has to travel and reducing the need for more packaging and longer storage/refrigeration periods.
However, food transportation is only one part of the emissions puzzle. According to a study by Weber and Matthews (2008), in the USA food transportation only accounts for 4% of the total emissions - with production emissions accounting for 83% of the total carbon emissions from food. To achieve the positive impact of eating locally-grown produce, we also need to eat seasonally. Eating local food which is grown out of season can actually result in a larger footprint than importing the food from elsewhere, due to the potential use of ‘hot houses’ to grow food in a non-native climate. For example, tomatoes grown during the winter in cooler climates using hot houses were shown to have a greater carbon footprint than importing tomatoes from warmer climates conducive to their natural growth – due to the production emissions being greater than the transportation emissions. Eating locally grown food, in season may help to reduce both the footprint of the food’s miles and its production.
Consumers and industry need to take practical steps to reduce food waste
It’s clear that we need to be taking the entire life cycle of our food into account if we want to ensure our dietary choices are greener – and this includes what happens to our food after we’ve purchased it. Figures from the Food and Agriculture Organisation of the United Nations, published in a study by Gustavsson et al, 2011, estimate that one third of the edible parts of food produced for human consumption globally gets lost or wasted – equating to approximately 1.3bn tons per year. According to Love Food Hate Waste (LFHW), if global food waste were a country it would be the third largest emitter of greenhouse gases. In the UK, the equivalent of 3.1 million glasses of milk get poured down the sink every day and we throw away the equivalent of one in five bags of food shopping – on average wasting £70 a month on food that ends up in the bin. While, in the UK, we have already made significant progress on reducing our food waste – saving £3.4bn a year and 5 million tonnes of CO2 compared to 2007 – it’s clear there is still work to be done. This means better practices for both consumers and industry.
As consumers, it’s time for us to accept that things are about to get ugly: according to an article in The Independent, “ugly” or “wonky” fruit and vegetables were to blame for up to 40% of food waste in 2013. While a report published in 2017 suggests our attitudes are changing, with more consumers buying unfortunate-looking produce, it’s estimated that up to 25% of apples, 20% of onions and 13% of potatoes are still being wasted on aesthetic grounds. This wastage isn’t just occurring at the point of sale – according to Wrap, a major cause of fruit waste is due to produce failing supermarkets’ aesthetic standards – for instance, strawberries are often discarded if they’re not the right size for supermarkets. Furthermore, in 2014 the National Farmers’ Union reported that approximately 20% of gala apples were being wasted prior to leaving the farm because they weren’t red enough. These figures suggest more openness to less-than-perfect produce is required – both from consumers and from retailers - in order to reduce waste due to aesthetic reasons throughout the supply chain.
There are also practical steps that consumers can take at home to reduce the amount of food we’re wasting. Tips from LFHW to reduce our food waste footprint include:
- Take a fridge temperature check: according to LFHW, the average UK fridge is actually set two degrees too warm – we should be ensuring our fridges are set to five degrees to keep our food fresher for longer.
- Freeze it: freeze fresh food, such as fruit and left-over cooked potatoes, before they go off and use them at a later date.
- Check before you shop: avoid making unnecessary purchases by checking the fridge and the cupboards before you head to the supermarket.
- Loose it and use it: opt for loose fruit and veg, rather than large multipacks, so that you can buy the amount you need and avoid the extra produce going to waste.
Industry practices also require improvement – both in terms of avoiding so much fresh produce going to waste before it makes it to the point of sale due to aesthetic defects, and in terms of how food is stored. Cranfield University is currently involved in an EU project led by Radboud Universiteit which aims to develop a storage system that enables businesses to detect defects and diseases in food before they end up becoming food waste. Cranfield’s research focuses on potatoes – currently they are stored in a closed storage environment making early detection of defects and diseases difficult, resulting in a food waste rate of up to 50%. The research looks to use laser sensors inside the containers which can detect volatile organic compounds – an early sign of spoilage. This could help to reduce food waste in the potato industry by enabling businesses to make better decisions on when to open and sell their products.
Whether you’re embracing the Veganuary challenge this January, or simply looking to make more environmentally-friendly food choices, it’s important to consider more than just what you’re putting on your plate. It’s more complicated than switching meat-based products for plant-based products – if we truly want our diets to be greener, we need to consider where our food has come from, the environmental impact of its production and avoid letting it go to waste.
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[1] Hess, T., Chatterton, J., Daccache, A., Williams, A. (2015) The impact of changing food choices on the blue water scarcity footprint and greenhouse gas emissions of the British diet: the example of potato, pasta and rice.