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Week Eleven - Food

Average Australian diet generates 1.4 tonnes CO2e per person per year

· Weekly experiments

My preschooler

- Lots of salt in my hollandaise, Mummy, but not too much lemon. And no truffles. I don't like truffles.


- I've failed as a parent, haven't I?

Cartoon of a fussy child ordering food

The Age of Consequences

In 1979, humorist Douglas Adams set out the three phases of civilisation, being Survival, Inquiry and Sophistication. He characterised these with three questions. How can we eat? Why do we eat? And where shall we have lunch? 

I believe we're now in the fourth phase of civilisation, the Age of Consequences. We should instead ask, What is the impact of my steak dinner?

My preschooler is clearly ready for Phase Three, Sophistication. But how will she cope with my Phase Four experiments over the next two months?

What is the carbon footprint of our food?

Food generates carbon dioxide and equivalent emissions (CO2e) in several ways. There's the agricultural impact to grow it - think fertiliser, feed and farting cows. There are emissions to transport it from the farm to the factory, the supermarket and the consumer, and more emissions to process it, pack it and to sell it. Depending on the type of food, there may also be emissions from cooking and refrigeration. Food waste also plays a big role.

Infographic showing that food generates carbon at different stages

Food generates carbon from paddock to plate and beyond.

I couldn't find an overall carbon estimate for the footprint of food, but agriculture alone accounts for around 13% of Australia's total emissions. What we eat matters.

What is the carbon footprint of my food?

I weighed and recorded all my food for a typical week, then estimated emissions using this RMIT literature review (a carbon league table for food based on 369 published Life Cycle Assessment studies). My spreadsheet is in the Notes section.

My food generated around 20 kilograms CO2e, just over a tonne for the whole year. On two days I ate mostly vegan, a diet that generated less than a kilogram CO2e per day. On three days I ate vegetarian with fish, cheese and eggs, generating two or three times as much CO2e. On the two days I ate meat, my emissions skyrocketed. If I ate like that every day, I'd double my carbon footprint from food.

A steak generates a lot of steak

My steak dinner was delicious but carbon-intense.

This one meal generated the same emissions as 5 whole days of vegan eating.

How does my food footprint compare with the norm? It's difficult to pick an average Australian diet, because people vary widely and it's difficult to get accurate data for an individual. We are notoriously poor at estimating, remembering and reporting what we've actually consumed and populations don't live in labs. I've used data for the Molloy family from the same study as my 'average' Australian diet.

Per person, the Molloy diet generated around 39.7 kilograms CO2e each week, or around 2.07 tonnes per year. This represents nearly 10% of the overall carbon footprint. It's more than household waste, flying and winter heating combined. That includes their drinks, which I'm not looking at now, so I'll run my own analysis for their food.

I'm certain I can cut back my own footprint and that of the Molloys without too much pain. If you're not a semi-vegan, steak-loving, truffle-sampling hippie, I suggest you follow the Molloy results rather than my own. I'll report against both for each week's experiment.

The experiments

Over the next two months, I'll run a series of experiments to cut carbon.

- Eat less. I'll test out the 5:2 diet and look at the carbon footprint of some other weight-loss fads.

- Eat vegan. This is the best-known way to cut carbon, but what are the tips and traps?

- Eat at home. The restaurant and fast-food industry is notorious for wasteful practices. What's their impact?

- Supermarket swap: high-impact for low-impact items. Simple swaps can cut carbon without going vegan.

- Less processing. Whole foods are hipster foods, but do they help the environment?

- Less food waste. Does food waste matter?

- Less packaging. War on Waste showed us the evils of packaging. Is it really that bad?

What if eating Green costs too much?

There's no point making a change that's too expensive to maintain. That's why I'll track and report costs as well as emissions. I suspect I'll find that eating green is cheaper than the standard diet, but I need to test this.

Food is essential, but we're not always sensible about its cost. I once had a colleague patiently explain that free-range eggs would never become mainstream because they cost $3 more per dozen. This man was single and earned over $100,000 per year, so buying free range would have cost him less than 0.08% of his salary (compare this to the Nigerians, who spend over half their income on food and still go hungry). He made a good point, just not the one he thought he was making. We Australians expect our food to be cheap.

For anyone genuinely struggling to put food on the table, please ignore my food experiments. You've got more immediate problems. In any case, you're likely already doing it right by not wasting food, accepting food donations and avoiding expensive and high-impact items.

Spreadsheet calculations, reference list and data discussion in the 'Notes' section, Week Eleven.

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