Five minutes with Professor Sarah Bridle

Interview

We chat with Professor Sarah Bridle, from the School of Physics and Astronomy at the University of Manchester and author of Food and Climate Change without the Hot Air, about simple hacks for eating more sustainably this January

How did you first get into working in food and climate change? 

“I hadn’t really thought much about climate change for most of my life; I was wrapped in trying to understand the mysteries of our universe, doing research in astrophysics for the last 20 years. Then we finished a big project, and my kids started school, and a friend and mentor tragically died – that all got me thinking deeply about what I wanted to do with my life.

“I pictured my kids in 20 years’ time saying “what did you do about climate change?” and me saying I looked at the stars – I couldn’t live with that. I started reading and learnt that food contributes about a quarter of all climate change at the moment, and that this fraction is rising. It seemed a really crucial and fascinating topic to learn more about. So I just sat and read research papers for a very long time, trying to understand the climate impacts of my own food choices, and it grew from there!”

What are three of the most surprising things you’ve discovered in your research?  

“I was surprised at the mismatch between what’s well understood by researchers on this topic, and what is known by the general public. It’s getting better known all the time, but ruminants (cows and sheep) cause a lot more climate change than most plant-based foods. For example, a steak and chips causes over 20 times the climate impacts of a microwaved potato and beans.

“Food miles are not always as bad as most people think. If food comes by boat then it’s not a big deal in terms of climate impacts; often the climate impact of the transport is similar to the climate impacts of producing the food. But transport by air causes 100 times as much climate change as transporting by boat. This means that, for example, a portion of vegetables by air can cause a similar climate impact to a small portion of low emissions animal product like chicken.

“Packaging isn’t as big an issue as a lot of people think. For example, the climate impact of a pint of milk causes about 20 times the climate impact of the plastic milk carton. In that case it’s more about what’s in the packaging than the packaging itself.” 

Is it necessary to give up meat completely in order to eat in a more climate-friendly way? 

“All food contributes to climate change, so there’s no need to be absolutist about meat. To take that steak and chips example; since steak causes most of the climate impact, then you can almost halve the emissions by halving the amount of steak.”

Can you suggest five climate-savvy food swaps? 

1. “Switch out beef for tins of lentils in a spaghetti bolognese and reduce the climate impacts of your dinner by six times. Or just add extra veggies, beans or lentils to your regular recipe and that will automatically reduce the amount of beef you have in each portion, and contribute lots of nutrients.
2. “Switch from chicken to chickpeas in your tikka masala, and switch from dairy to nut butter in your sauce. This will reduce the climate impact of your dinner by three times. 
3. “Instead of switching the oven on for two hours to bake a potato, try microwaving it instead. If you do that and switch cheese and butter topping to relish and beans, you can reduce the climate impact of your baked potato by six times. 
4. “Try peanut butter and jam instead of cheese and dairy butter in your sandwich to reduce the climate impact of your lunch by five times. Even though the peanuts come from overseas to the UK, they come by boat.
5. “Switching from dairy milk to plant milk with your cereal can halve the climate impacts of your breakfast.” 

Are there any other tips you can give for being more sustainable when it comes to food? 

“I think the best way to start is to find out what parts of your regular diet causes the most climate change, and then start thinking about quantities. Could you reduce the quantity you have of those foods in each meal? Often that’s easier than cutting out foods altogether. 

“Sometimes people come up to me and say they’re already doing X, Y, Z – loads of things to help climate change – and what more can they do? Those people are probably causing less than half the climate impact of the average person already, and reducing that further gets really hard and has less impact on climate change than helping other people to change their diets. So spread the word!”

What do you think is the biggest myth about eating sustainably?  

“It’s difficult for consumers to know how big all the different factors are. For example, how food transport contributes to climate change compared to farming itself. How can consumers be expected to know whether pulses and nuts brought by ship are better or worse for climate change than meat produced locally? But in fact, usually it’s the growing of plants and the raising of animals that causes the biggest climate impacts, above and beyond the transportation. So, although meat produced locally can be better than the same type of meat from far away, it’s still usually worse for climate change than plant-based products – so long as they don’t come by air.”