Tag Archives: Carbon Footprint


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:

  1. Land use change: above ground changes caused by deforestation or below ground impact on carbon in the soil.
  2. Manufacturing: crop production, fertilisers, animal feed, livestock gas emissions and food processing.
  3. Retail and Packaging: Warehousing, refrigeration, lighting and both manufacturer and disposal of packaging.
  4. 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:

  1. Eating beef once a week rather than twice a week will save almost a tonne a year of carbon emissions
  2. Replacing cow’s milk with oat or soy milk will save 290kg a year
  3. 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:

Reducing my family’s carbon footprint

Here’s a first blog on my efforts to reduce my family’s carbon footprint to a sustainable level. To reduce it I need to measure it, and this is a lot harder than I had ever expected. The first instalment of my efforts to calculate my family’s footprint and become (more) climate positive will hopefully provide you with some of the tools you need to do the same.

The Singapore government is fantastic with online publishing of data. And the Climate Change Secretariat tells me that Singapore emits a little under 9 tonnes of CO2 per year per capita. On first inspection, this seems very positive, less than half the US per capita figure.

But digging into this number, I discovered it isn’t the average footprint of a Singaporean. It is the total emissions of Singapore (excluding international transport) divided by the number of people. The carbon emitted in the process of growing food in other countries and then shipping the edibles to Singapore isn’t included. As the food chain contributes about 25% of global emissions and Singapore imports 90% of its food, and as the average Singaporean takes more than three flights out of Changi a year, there were going to be a few sizeable differences between the 9 tonne figure and the average footprint of a resident.

On top of this, I don’t own a car, but I probably fly more than most, so my individual footprint likely would be very different to the average. The journey on which I commenced was not pretty.

I set about trying to calculate our family’s carbon footprint. Despite their being innumerable footprint calculators online, after a lot of googling, all seem to make assumptions that were just not be valid for me.

For example, the carbon calculator touts itself as the world’s most popular. However, it suggested that my electricity usage produced only 2.21 tonnes of carbon a year. A quick calculation using Energy Market Authority data showed that in fact my family is responsible for over five tonnes of emissions.

The Polish government do a good calculator, but it calculated that we emitted 11 tonnes of CO2 from air conditioning. As this is a subset of electricity, this was way off too.

It seemed the only solution was going to be understand the key contributions to a carbon footprint and then calculate each part separately based on data specific to Singapore and specific to our family.

The main constituent parts for a family seem to be five segments:

  1. Transport
  2. Food
  3. Consumption (iphones, clothes..)
  4. Energy (electricity, gas..)
  5. Society as a whole (government, police, hospitals, water supply, road building..)

I’ve split food down into that eaten at home and in restaurants, and transport into flights, public transport and taxis.

My current best guess is that my family emit a whopping 50 tonnes of carbon a year. Sustainability advice is to emit 2 tonnes per person per year. So we need to find ways to cut about 85% of this if we want to be sustainable.

I’ve made a million assumptions in formulating this, which I expect will be refined as my understanding grows. If you’re interested in the calculations and assumptions behind these figures, I’ve written a separate blog on it here.

We cannot impact the ‘Society as a whole’ footprint, which represents the government, police, hospitals, water supply, road building etc. So I’ll assume we need to cut everything else to be sustainable. It would be impossible to do this without employing offsetting or carbon capture to some degree – we would not be able to eat.

My goal is to change the world, not my day. I want to cut as much as I can as cheaply as I can and then offset the rest.

So where to begin

The easiest place to start is electricity. Singapore has recently deregulated the electricity market, so am switching to a 100% solar tariff. This cut 5 tonnes out and actually saves me 290SGD/year.

Flights are another huge chunk. And because the emissions are higher in the atmosphere, the non-CO2 components are even more impactful, around twice as much so. I still want to see places and as much as I would love to, I don’t want to change my lift to give me time to take the train everywhere, so there are two tangible ways to make a difference here.

  1. Travel only on efficient aircraft. The calculations are based on an ‘average’ aircraft, Using only the most efficient Boeing 787, 777 and Airbus A350/320/330 reduces carbon emissions by about a quarter.
  2. Take only direct flights. 25% of the emissions on a flight occur during take off and landing. Flying direct (assuming the plane is mostly full) is more efficient per passenger.

I’ve decided to take both these options and offset the remaining 11-12 tonnes using goldstandard.org where I support a project providing clean water filters to families in Laos enabling them to avoid burning wood to boil the water to make it potable. This costs me 144SGD/year.

With just these two actions we have eliminated or offset 20 tonnes of annual emissions, 40% of our total. We’ve also saved net 134SGD/year.

In the next blog, I’ll look at how to more accurately measure and then reduce the consumption and food segments – the next largest contributors.

Key takeaways

The easiest ways to cut your carbon footprint and change your day and not your life if you live in SIngapore are:

  • Switch electricity providers to a 100% renewable supplier
  • Fly on airlines that use Boeing 787/777 or Airbus A350/330/320s. Avoid Boeing 747s or Airbus 380s. Offset the remainder of your emissions, including the radioactive forcing, when you fly.