Sarah Bridle
Professor Sarah Bridle is Chair in Food, Climate and Society at the University of York. A transdisciplinary researcher galvanised by the need to tackle climate change, Sarah takes a quantitative approach to help transform agri-food systems. Sarah’s aim is to drive changes in food production and consumption towards healthier people and planet, through research focused on exploring and communicating the environmental and nutritional impacts of different interventions.
Author of Food and Climate Change - Without the Hot Air, Sarah founded Take a Bite out of Climate Change, leads the Metrics Work Package of FixOurFood, and was appointed Food and Land Use System Fellow in the Chief Scientific Adviser’s Office at DEFRA in November 2021. Regularly leading discussions with stakeholder groups in the food system as well as policy and science influencers, Sarah directs multiple outreach projects, is Co-Primary Investigator of the AgriFood4NetZero Network+ and heads the Network’s Communications programs.
Writers Rebel’s Katie Percival interviews Professor Sarah Bridle, a UK-based interdisciplinary researcher and writer concerned with what our food system is doing to climate change, and what we might need to do to fix it.
Katie Percival: Your background is as an astrophysicist, but in the last few years you’ve turned your attention to climate change, and in particular, the role of our global food system within it. Could you tell us what prompted this change?
Sarah Bridle: I finished a big project in cosmology about five years ago, by which time I’d been working in the field for 20 years. And I started wondering, what about the next 20 years of my career? At around the same time my kids started school and I got to thinking, what will the world be like for them in 20 years’ time? I imagined them, saying “what did you do about climate change mummy?” and me saying, “you know, I looked at the stars” and feeling like that was not really something I could live with. At the same time, a former mentor of mine, David MacKay, became terminally ill and he had done a huge amount to improve the quality of discussion about energy sources and the energy transition. I felt I needed to learn more about climate change. What I learned was that food has a big impact on climate change. It’s a fun and interesting topic, and it just seemed fascinating to learn more about it. The more I read, the more interested I was, and it became a bit of an obsession, really.
KP: Your book, Food and Climate Change – Without The Hot Air, published in 2020, was quite influential for me. It helped me to understand some of the complexities of global food production, both on a whole system level and on the individual’s choices within it. How do you think the food and climate change conversation has moved on since it was published?
SB: A few years ago the conversation was around creating more awareness about the climate impacts of different types of food. I think now everybody’s on board with the idea we need to change the system. Things have definitely changed since I started writing the book, thanks also to groups like Extinction Rebellion and the school climate strikes, but also big reports like the IPCC that have identified food much more visibly as an important part of climate change. Farmers are strongly affected by this topic and maybe three or four years ago this might not have been on their radar until my colleagues and I started talking loudly about it. Nowadays there are a lot more people talking about it than there were before, so I don’t feel like I’m in the firing line so much. We may not necessarily agree on the solutions, but at least we agree that it’s an issue.
KP: What do you think is the biggest myth circulating about the impact of our food system on climate change and planetary health?
SB: I’m wondering which one to pick out of lots of different myths. There are lots of myths circulating about food miles, and before I started looking into this I was certainly concerned, like many others, about the impact of, say, bananas being transported from distant places like South America. But to take bananas as an example, they are transported to the UK by boat, and the emissions involved in the transportation of bananas by boat roughly equals the emissions involved in growing them in their country of origin, and it’s very clear now that the likes of bananas do not have a huge impact on a diet’s carbon emissions. If the same fruit was transported by air the emissions from transportation would go up 100-fold, but companies don’t transport things by air unless they absolutely have to, because it’s much more expensive. If a foodstuff will keep in your fridge for a week, then it’s likely to be OK in the hold of a boat under carefully controlled conditions for a few weeks. I think it’s worth, as a consumer, shifting our focus to how much we in the northern hemisphere really need to buy the likes of strawberries in December, for example: foodstuffs like berries, asparagus and green beans would perish in the hold of a boat so they are transported by air if they’re coming from a distant continent.
It is slightly more interesting is to think of something like a mango which, as a whole fruit, can keep for a long time so would arrive in the UK by boat. But if it’s a pre-sliced mango then it’s likely to be sliced in the country of origin because the labour’s cheaper, and so would have to be flown into the UK. It’s those kinds of things that are not easy to discern as a consumer. Could we label food as ‘air freighted’ or ‘not air freighted’, for example?
Packaging is another area that has a lot of myths surrounding it. Many people think that by reducing the amount of packaging their food comes in, they are making a big difference to its climate impact when in fact they’re not. As an obvious example, I saw a Tweet recently about a new initiative that has installed taps at various locations where customers can come and bring their own bottles to fill up with milk directly from the farm and save on the plastic bottle. But if you’re driving all the way there to fill up your bottle then the benefits are immediately undone by the petrol you’ve used to get there, which entirely misses the point. In fact, the packaging used for even a small plastic carton of milk constitutes less than 1/20th of the milk’s total climate impact – and less than that for larger cartons. It’s the milk itself that contributes the lion’s share of emissions. There are obviously other good reasons to reduce our use of packaging but if we think we’re solving climate change just by reducing our packaging, we’re wrong.
Another myth surrounds making things from scratch at home. Some people think the best solution is to make everything from scratch, and though there may be many reasons why this might be desirable, climate change isn’t one of them. We might put the oven on and make a loaf of bread rather than getting a loaf that’s been made by someone else in a big industrial oven, but we can be much more energy efficient by using the economies of scale that you get by having things made in bulk. Another issue with that is by-products. You might chop up your cauliflower and then you’re left with all the leaves and that’s great if you can put them on the compost bin if you have one, but if not, they go in your general waste bin and then to landfill where they decompose in wet conditions which releases methane into the atmosphere. So as well as not using energy as efficiently at home, you might not be managing waste as efficiently either. A lot of people are unaware that in the UK about 70% of food waste happens at home.
KP: The EAT-Lancet report estimates that global food production is responsible for about 30% of the world’s carbon emissions and 70% of freshwater use. The report stopped short of suggesting how nations and industries might wish to tackle these issues. What do you think is currently the biggest barrier to the adoption of processes that reduce the carbon footprint and resource use of our food system?
SB: I think it’s important to look at food on a system level. Not everybody’s got a choice in what they eat. There are three main things we can do in terms of system-level change: look at production methods, reducing waste and dietary change. It’s worth noting that if we don’t do dietary change, we can’t do what’s needed in terms of reducing the climate impacts of food.
From a production point of view, I think it’s hard for us to understand how challenging it is to be a farmer in terms of implementing new equipment or new ways of doing things. There’s often a short-term reduction in profits and a longer time scale in terms of when the payback starts to happen. If you’re a tenant farmer and you’ve got a lease on your land that’s two years long, it’s hard to justify starting a new farming practice that sequesters more carbon and will increase yield in the long-term because you might not even have that land in two years’ time.
In terms of dietary change, we need new policies, new governance, new ways of doing things; it could be as large as a government level policy or it could be as small as a canteen policy. To change those things, we could do it quietly without anybody noticing, maybe reducing the quantities of the most climate impactful foods in the menus on a canteen. On the other hand, if you’re going to announce it, then you’ve got to get people bought in. We’ve had school canteens announcing Meat Free Mondays and that has been met with backlash, so we’ve got work to do changing the public’s perceptions. I look at the way that public perception of plastics has changed over the last five years – and not always in a totally informed way – and now we have governments, supermarkets, food producers falling over themselves to tout their low-packaging, plastic-free policies. Could we ever get to that point with climate friendly foods and policies? That’s the dream, I think, to get to that point where people are clamouring for those things to happen.
KP: Leading up to the release of Food and Climate Change – Without the Hot Air, there was a lot of discussion around food justice, which is to say: is it fair for people in wealthy nations who cause the climate and ecological crisis to ask those in developing nations to curb their appetite for the high footprint diet that affluent nations have enjoyed for the past 50+ years? What are your thoughts on how we might address this and adopt a fair transition to lower carbon eating?
SB: Research has shown that as wealth increases, people tend to eat more food that has greater impact on the climate, specifically meat. As people have become better-off in some lower and middle-income countries over the last few years, they have started to eat more meat and that is one of the things which is driving the overall global quantity of meat that’s being eaten. When you look in detail at the amount of meat per head eaten in these developing countries, it’s still relatively low compared to what we’re eating in Western countries. It seems desperately unfair to me to point the finger at people who are increasing something which is still below our own level of consumption and say it’s their fault. Until we’re eating a diet which could be eaten by everybody while keeping us below a threshold of exceeding planetary boundaries, I don’t feel we can throw the first stone. We need to figure out a diet that everybody could eat sustainably.
KP: When I heard you speak at an event back in 2020, you were keen not to promote a plant-based or vegan diet as the solution to our food system problem. Do you still feel this way, and what other issues are at play?
SB: I’m personally not too bothered how we solve this problem of the climate impact of our food, so long as we solve it. You can, of course, follow a vegan diet but still have a high carbon impact, by eating air-freighted foods or travelling to do your food shopping in the car, for example, so it’s not just about vegan versus not vegan. And the second thing to think about is, what are the merits in being absolutist? When I first heard about the impact of climate change, I was so shocked that I went plant-based for a year, and for me, cutting milk out of my cup of tea was just a horrific thought that made me feel so sad. When you look at the climate impact of having a tablespoon of milk in a cup of tea, it’s really not that bad. With hindsight I would have been much happier if I’d had that bit of milk in my tea, while changing my diet in other ways which had a much bigger impact than going all out and doing something which was not necessarily sustainable for me in the long term. I think it’s much more important to think about the quantities of food with a high climate impact that we as individuals eat. For each person who is willing and able to change their diet, it’s about trying to figure out what are the most climate impactful things you’re eating and reducing the amount and frequency with which they’re eaten. This is, I think, a more effective way of getting people on board and making meaningful changes.
KP: You’ve been campaigning on food and climate change for at least the past four years, and during this time, the messaging around climate change has been getting progressively more dire! Is there cause for optimism within the global food system, and any big wins that you can share with us?
SB: To make a change you need a trigger, and I guess we’ve had a few different triggers recently: the pandemic, the war in Ukraine and now the cost-of-living crisis that are causing changes, and mostly not good ones. But on the other hand, when there’s a big change there’s an opportunity for building back better. Can we change our diets in a way that also frees up land that we can use to sequester carbon? I think there is reason to be hopeful, but sometimes things get worse before they get better, and maybe that’s where we’re heading in the short term.
KP: You have said that the biggest impact we could have on changing our food system for the better is by lobbying supermarkets to label the greenhouse gas emissions of the products that they sell. Have you seen any progress with this in your sphere of work?
SB: We need mandatory labelling, whether it’s by supermarkets or other retailers. The food producers would need to do the calculations, but it would have to be done on a level playing field, so ultimately, this mandate needs to come from the government. There may be other ways of increasing transparency that are easier to implement in the shorter term, such as simply raising awareness of the academic literature about the climate impact of foods. We’ve created a resource called Take A Bite Out of Climate Change (www.takeabitecc.org/) which aims to help educate individuals and schools about the climate impacts of the food we eat.
Professor Sarah Bridle is Chair in Food, Climate and Society at the University of York. A transdisciplinary researcher galvanised by the need to tackle climate change, Sarah takes a quantitative approach to help transform agri-food systems. Sarah’s aim is to drive changes in food production and consumption towards healthier people and planet, through research focused on exploring and communicating the environmental and nutritional impacts of different interventions.
Author of Food and Climate Change – Without the Hot Air, Sarah founded Take a Bite out of Climate Change, leads the Metrics Work Package of FixOurFood, and was appointed Food and Land Use System Fellow in the Chief Scientific Adviser’s Office at DEFRA in November 2021. Regularly leading discussions with stakeholder groups in the food system as well as policy and science influencers, Sarah directs multiple outreach projects, is Co-Primary Investigator of the AgriFood4NetZero Network+ and heads the Network’s Communications programs.