Saving the planet, one meal at a time

close up of row of cows being milked
(c) Toa55

Dr Neil Jennings, Partnership Development Manager at the Grantham Institute, and Lily Peck, Research Postgraduate on the Science and Solutions for a Changing Planet Doctoral Training Programme, explain how eating a more plant-based, seasonal diet can help tackle climate change, support the local economy and help us to live healthier lives.

For most of us, shifting to a more plant-based diet and reducing meat intake is the single biggest action we can take to reduce our impact on the environment. In this blog we look at why a plant-based diet can help reduce the impacts of climate change and how we can reduce the environmental footprint of our diet by eating more seasonal and locally-produced food.

What is the environmental impact of food?

Around 26% of global greenhouse gas emissions (GHG) come from the agriculture sector – if it were a country, it would be the second largest emitter in the world. Over half of these emissions come from animal-based products. The production of beef and lamb is responsible for a disproportionate share of these emissions because, unlike pigs and chicken, cows and sheep ruminate – meaning their food ferments in their multi-chambered stomach. This causes them to burp and fart relatively large amounts of methane, a greenhouse gas that is 28 times more potent than carbon dioxide. (As an aside, an interesting pub quiz fact is that cows emit more methane from burping than farting!).

A high-meat diet produces 2.5x more greenhouse gas emissions than a vegan equivalent - with a bar chart showing the relative emissions for different diets

A vegan diet isn’t carbon neutral – agricultural practices certainly need to be improved to reduce GHG emissions across all food types. However, a diet that is high in meat (over 100g/day – roughly two sausages or one beef burger) produces around 2.5 times more GHGs than a vegan diet. Meat and dairy will always have a higher environmental impact than plant-based products because each organism in the food chain requires more food, water and other resources than the last. To produce a kilogram of beef, for example, you need between five and twenty kilograms of grain. Put simply, eating meat is an inefficient way to get the nutrients we need. As the infographic below shows, you can eat nine falafel burgers for the equivalent GHGs produced by one cheeseburger!

To find out more about the impact your food choices have on water use and GHG emissions, check out this BBC webpage – the direct comparison of dairy milk alternatives is particularly insightful (lots of us in the office have moved to oat milk now rather than dairy as a result).

The carbon footprint of one cheeseburger is equivalent to... 9x falafel and pitta and 6x fish and chips (both illustrated with a graphic)

Can you get enough protein with a plant-based diet?

In the UK, the average person eats 45-55% more protein than they need each day, so the majority of people can reduce their meat consumption while easily getting their recommended daily protein intake. In some cases, plant-based options can be as high in protein as their meat or dairy-based alternative – soy milk, for example, contains 3.3g of protein per 100ml, which is the same as dairy milk. If elite athletes like Serena Williams, Lewis Hamilton and Lionel Messi can get enough protein in their diet without meat, it’s fair to assume those of us with lower protein requirements shouldn’t struggle!

Plant-based or lower-meat diets not only have a smaller impact on the environment, but are also often the healthier choice. Diets that are high in red (e.g. beef, lamb, pork) and processed meats (e.g. bacon, sausages, salami) are associated with higher levels of heart disease and certain types of cancer. As such, reduced meat intake can help to reduce rates of obesity and type-2 diabetes – saving the NHS money in the process.

Why does seasonality matter?

Another simple way to reduce the environmental impact of your food is to eat locally-grown food that is produced in its natural season. Both parts of this are important: locally, because this reduces the emissions produced in chilling and transporting the food; and in-season, because this reduces the emissions needed to produce it – heating and lighting a glasshouse to grow strawberries in winter is much more energy-intensive than letting the sun do it for you in spring and summer!

Something is always in season somewhere, hence the year-round availability of everything from Peruvian asparagus to New Zealand apples. When apples are harvested in the United Kingdom in the autumn, some are sold fresh and the rest are stored at 1°C for the rest of the year. If you want to eat an apple in the spring, your choices are apples that have been stored in the UK using twice the energy as a fresh UK apple in autumn, or apples transported from New Zealand, which use nearly three times the energy as a fresh UK autumn apple due to the distance involved.

Check out our seasonal calendar to see when our favourite foods are naturally available in the UK, and this detailed BBC guide to help you plan your meals to maximise the freshness, quality and diversity of your diet while also reducing your environmental impact.

Eat local, seasonal food to reduce your carbon footprint - graphics showing a box of seasonal food, with labels, for each season of the year.

Waste not, want not

The total volume of food wasted each year could feed nearly 1 billion people, and food waste is estimated to make up 8% of global GHG emissions – a shocking statistic given that there were nearly a billion hungry people around the world in 2017. Global population is expected to reach 10 billion people by 2050 (up from 7.7 billion now), so producing enough food for a growing population poses a significant challenge to our ability to preserve biodiversity and soil quality, and limit GHG emissions.

In developing countries, most food waste happens before it even comes close to our plates, with crops rotting in fields because farmers cannot harvest them. Conversely, in developed countries people waste food when it rots on our shelves and in shop bins. Reducing food waste across the board should be a priority for helping to feed a growing global population – while also reducing GHG emissions.

On a household level, the best ways to reduce food waste are to plan your meals ahead of time so you only buy what you need, and either re-use or freeze any leftovers – this will save you money at the same time. Love Food Hate Waste have great resources to help, including recipes for your leftovers!

Where to go from here?

Of course, the environmental footprint of food extends beyond GHG emissions – with impacts on water, land use and biodiversity. We’ve covered a number of important areas in this blog, but there is much more that could be discussed, such as how the demand for palm oil is causing the destruction of virgin tropical rainforests, how sugar-cane production is destroying parts of the Great Barrier Reef, the impact of certain agricultural practices on soil erosion, the rise of antibiotic resistance or, on the positive side, how Scottish salmon farmers are using cleaner fish to reduce their use of chemicals in their farms and subsequently in the environment.

Reducing the environmental impact of food is certainly not simple, and solutions will require collaboration and cooperation between governments, businesses, farmers and the public. But, on a personal level, you can reduce the carbon footprint of your diet by eating a more plant-based, seasonal and local diet. You’ll also be living a healthier life.

See our leaflet about how you can help tackle climate change, one meal at a time.

Find out more about how you can make a difference on climate change.

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