After the actions we took last year to reduce or eliminate 20 tonnes of our family’s carbon footprint, the next major contributor to attack is the food we eat, either at home or out in restaurants. Last year, I had estimated this at 12.5 tonnes of our remaining 30 tonne footprint.
Since the first in this series, our eating and cooking habits have materially changed: I am working from home, so eating at home every lunchtime, and we eat out about half as much as a family. I’ve also realised I hugely underestimated the percentage of our food that is air freighted to us from Australia or Europe. Overall, I still estimate our food footprint to be about 12.1 tonnes a year. This isn’t unrepresentative, food production represented about a quarter of our pre-cut emissions and is likely responsible for about a quarter of the world’s carbon emissions overall.
A reminder: the ultimate goal is for my family to become carbon negative, by reducing our footprint wherever I can, and offsetting the remainder. With hope, these posts influence others to do the same, turning our footprint negative. I am going about this in a completely data driven manner, by analysing where we are responsible for carbon emissions, then making changes to our choices that have the minimum impact on our lifestyle, but the maximum impact on sustainability. As I am doing this, I’ll give the sources of data and the approaches for you in this blog so you can make your own informed decisions.
Food carbon emissions have four major components:
- Land use change: above ground changes caused by deforestation or below ground impact on carbon in the soil.
- Manufacturing: crop production, fertilisers, animal feed, livestock gas emissions and food processing.
- Retail and Packaging: Warehousing, refrigeration, lighting and both manufacturer and disposal of packaging.
- Transport: Getting to product from manufacture to retail in a boat, on plane, in a truck, on a donkey or the like.
Land use change is significantly more impactful than I had expected. For nuts, land use change actually flips the impact to be negative. For Brazilian beef, the land use change can be higher than the other three combined.
Transport is also very important for you to assess. In many calculations, it is assumed you food is transported largely by surface. Only .16% of global food-miles are air miles, so this is largely fair. However, in Singapore, 90% of food is imported, with many options available to import fresh meat, fish and short shelf-life fruit and vegetables from Australia and New Zealand. Whilst apples, bananas or pumpkins may well be surface transported, it is highly unlikely that fresh beef or salmon don’t go through an airport.
Breaking down our footprint
The estimate of 12.1 tonnes broke down as follows:
a) 6.0 tonnes from food used to eat at home (categories 1, 2, 3)
b) 2.8 tonnes in transport (category 4)
c) 3.3 tonnes from eating out.
I’ll go into detail on how I calculated the a) and b) below. For c) I assumed a flat rate of 8.5kg per meal eating out, see reference below. By way of comparison, the equivalent figure I calculated for a home-cooked meal is 6.2kg (4.2kg of food and 2kg of transport). Chris Ying has estimated a home cooked meal uses 8kg of carbon, including electric energy and other costs I have attributed elsewhere – giving me confidence my figures are not way off.
To calculate a) – the impact of food bought to cook at home, I looked at the 34 foodstuffs we bought in any quantity and reliably over the period of an average month, with a specific focus on those I know to be carbon intensive: meats, dairy, and luxury air freighted items like chocolate. The items ranged from nuts with a negative impact, to Australian beef, which has an impact of about 9kg per 150g steak (excluding transport).
To calculate b) transport, for each foodstuff, I estimated its packed weight and whether it was air, sea or land transported, and used an average CO2 emission per tonne kilometre to give the overall impact. I couldn’t find any use of donkeys.
Summarising the 6.0 tonnes of direct food impact into seven main groups gave me the following breakdown:
In short, we could halve our emissions if we just cut out beef, eggs, milk, butter and cheese. Giving up cheese would remove one of my great pleasures in life (which was not the purpose of this activity – yet), but three small changes allow us to reduce the 6 tonnes by over 20% to 4.7 tonnes with no pain at all:
- Eating beef once a week rather than twice a week will save almost a tonne a year of carbon emissions
- Replacing cow’s milk with oat or soy milk will save 290kg a year
- Drinking more wine and less beer will save me 75kg a year.
Once I had factored in that our milk and beef were both air freighted in from Australia, the overall savings were 2.1 tonnes per year. To cut this materially further, we’d need to cut dairy out almost completely. Interestingly, a pint of beer uses about three times as much carbon to get to my mouth as a 150ml glass of wine. So as the wine seems better for the environment and also gives me a much brighter morning after, this was a real no brainer.
Consumption will be the topic of the next post, but ahead of a more thorough analysis, I have looked at the impact of nappies. A 35 page DEFRA article (linked below for your reading pleasure!) fascinatingly points out that purely from a carbon footprint angle, disposable nappies are actually lower in impact than reusable ones, once washing and drying have been factored in. Disposable nappies have an impact of around 200kg/yr.
My wife has immediately started potty training our daughter!
Where we stand as a family
So overall, we’ve managed to reduce our footprint by 2.3 tonnes a year through the actions in this post and are now down to 27 tonnes a year. Of course, as we are not flying at all, the 14.5 tonnes we had previously been offsetting are now cut, at least until borders re-open.
We have cut out 44% of our carbon emissions as a family in a year. A proud beginning.
I’ve used three main sources to estimate the carbon footprint of food:
These articles helped me understand the carbon impact of food and travel:
This is the 35 page DEFRA analysis of nappies
And finally, the calculations of the carbon footprint of a restaurant meal: