Friday, 28 August 2020

Food and climate change without the hot air by S L Bridle – review

Published by UIT Cambridge Ltd. Available free in electronic form or currently £15.99 from Blackwells

I really like this book. It works on many different levels in different ways, for different sorts of people. I recommend it to all my family and friends, not just the geeky ones.

If you’d like to reduce GHG emissions from your diet, without going entirely vegan, it suggests changes you can make which will have a significant impact. It also tells you which things you don’t have to worry about. For example, coffee with milk and sugar has more emissions than black tea but they are both dwarfed by a latte because it has so much milk. For lunch, a ham sandwich has lower emissions than a cheese sandwich and a chicken sandwich is even better. But if you go for plant protein sources like peanut butter you can halve the emissions again.

The coloured charts showing the emissions of different foods are all drawn to the same scale, so it is easy to compare foods discussed in different sections of the book just skimming through the charts. This makes it glaringly obvious which foods have the highest impact - a serving of beef or lamb barely fits in the height of a page.

An illustration for the book, showing per-person emissions from baked beans cooked different ways.

If you want to know why some foods have higher emissions than others, you can explore the topic in any depth you like. The main text is very readable and in addition Bridle has written notes on her methodology and sources of evidence and full references. Did you know that rice paddies generate a lot of emissions? So you can reduce your impact by eating your curry with naan bread instead of rice. However, farmers can reduce the emissions from rice by flooding the paddies only part of the time, just enough to keep down the weeds. Bridle also mentions additives for cattle feed to reduce methane emissions and following those references (in an early version of the book) stimulated my blog post on Beefing about Meat.

It is written in bite size chunks, but is amazingly comprehensive. Most of the book is structured as menu choices for meals and snacks, from breakfast through to dinner including dessert and drinks. If you read the whole thing you will have explored all the important issues including meat/dairy proteins, food air miles, plastic packaging, cooking methods, organic versus inorganic and nutrition issues around different food choices. Beware the low protein vegan "cheeses"! (Though the better ones can be good, made with tofu or nuts instead of oil and starch, another thing I learned from this book).

Part 2 discusses a variety of possible dishes for lunch.

Bridle avoids getting bogged down in unnecessary details. I have delved into food emissions a few times, both for my book and in this blog. Food is an area where I have to to metaphorically put on blinkers before diving in because it is so easy to get distracted by details. Where does the food come from, how was it grown, how was it packaged, stored, transported, cooked? What happens to the waste? All these can have a major impact and they interact. For example, using precooked cans of beans is less emissions than buying them dry and cooking them at home – unless you cook in larger quantities using a pressure cooker. Bridle explains the issue with a few sentences and a well-placed chart (shown above). At the end of each chapter there is a list of 'key points'. Here are the key points from chapter 9 on the cheese sandwich.


There are areas where you might say she has glossed over some of the complexities but you have to stop somewhere. Is your beef from Argentina or Herefordshire? Do you have a gas oven or electric? Bridle is transparent about her assumptions and they are not unreasonable. I would have used a lower figure for emissions from producing electricity, based on the UK context but food is produced and consumed across the whole world. 

Bridle is not a career food scientist, in fact she is a professor of physics at Manchester University specialising in analysing large cosmological datasets. You may think that exploration of dark matter and gravitational lensing are rather a long way from beef, rice and plastic packaging, but I am sure similar skills are required. In both cases you have a lot of data generated by complex processes with noise, uncertainty and many variables - your first task is to you to navigate through all that and get to the core truths; the next to explain to the rest of us what it means and why it matters. Bridle does this admirably. Knowing how difficult this is I really appreciate her skill - and the amount of research effort that has gone into writing this book.

If you don’t fancy reading a book, try watching her Ted Talk or download the flash cards from her website. Bridle has other resources there for children to have fun learning about climate change and food issues – and all for free.


  1. You claim: "Available free in electronic form"

    I say that you've drunk the Kool-Aid. It's not free; I first have to purchase an Amazon device, or try to read it on a stupidly small screen on a device where I have downloaded an Amazon app.

    Or is there somewhere else I *CAN* download it for free?

    1. Is epub any good? Try here

  2. I can't see how to get an actual file. If you go there there is no download link, but if you get a kobo account it's possible to add the book to 'my books', and hidden under 'other actions' is 'download'. But that doesn;t download the book, it downloads an acsm file, which I understand to be a link to a proprietary Adobe system which so far as know cannot be used on linux.
    So I have not yet found a way of just getting the book (PDF, epub would be fine). Cambridge public library is the same and just delivers acsm files which I can find no way to use, rather than books. I'm not sure how Adobe managed to insert themselves into all book publishing like this, but it seems bad...


Comments on this blog are moderated. Your comment will not appear until it has been reviewed.