My kindergartner

- Mummy! I can't find my bloodyfrickin pony! Where's my bloodyfrickin pony?

Me

- Two things. You need to clean your room. I need to stop swearing when you're around.

Stuff = CO2e

As famously observed by Tony Abbott, carbon is an 'invisible substance' that we can't see. This makes it hard to weigh up how much of it we use and where we should cut back. When we think about carbon, we usually picture the petrol in our cars, the electricity in our grid or a politician cackling over a chunk of coal. But pretty much everything in modern life is made with carbon dioxide and equivalent emissions (CO2e).

Think of those modern consumerist icons, the Little Shop and Ooshie toys. They're plastic, which means they're made directly from fossil fuel. While the budding bioplastic industry might one day bring us an Ooshie made from plants, its primary ingredient would still be CO2e. Whether the material is corn starch, bamboo or mermaid tears, we'll need to harvest or mine it, refine it, mould it, transport it and sell it. Each step in that process takes energy - this is the toy's embodied energy. Generating that energy leads to carbon emissions - this is the toy's embedded emissions. And even clean, green renewable energy contains embedded emissions, as I discovered in Week 31. We can make things using less CO2e, but we can't make them without CO2e.

In previous weeks, I found that per person per year, food, drinks and pet food are responsible for around 3.5 tonnes of embedded emissions. So how much is in the other stuff we buy?

What are those toys really made of? Plastic or carbon?

How much carbon is in our stuff?

According to 2015-16 ABS data, the average Australian household spends over $10,000 each year on clothing, footwear, household furnishings and other goods and services. Exactly what do we buy and how much CO2e is in it?

Government and industry data on consumer habits looks at how much money people spend. This doesn't help my carbon analysis. I don't care if you blew $1 or $1000 on jeans. I want to know how many pairs you got and how many grams of fabric each contained. I couldn't find this data so I came at the problem from the other end. What do we throw out?

According to the 2018 National Waste Report, Australians generated 54.5 million tonnes of core waste each year. This includes 15.5 million tonnes of metal, paper, cardboard, plastic, glass and textiles, which should cover most of the toys, clothes, furniture, electronics and other goods we buy. Using some crude assumptions to deduct commercial and construction waste, I estimated that the average Australian throws out around 234 kilograms of this stuff each year. If it's made from virgin material, it represents around 832 kilograms embedded CO2e per person per year. Interestingly, if all this stuff was made from recycled or reused material, it only represents around 277 kilograms CO2e per person per year.

What about the CO2e from my family's stuff?

I did a bottom-up audit of the clothes, toys, sports gear, books, electronics and household items my family bought. I found we were below average on expenditure at around $7,500 per annum. We ran much lower on quantity at only 43 kilograms of stuff per person per year, which generated a modest 186 kilograms CO2e per person per year. This was largely thanks to our second-hand purchases, which were fifteen times less carbon intense than the stuff we bought new. Sports gear was our biggest source of emissions, thanks to my stand-up paddleboard and my partner's new bike, both of which contain a lot of material and are therefore carbon-intense. Clothing was our next biggest source of emissions. And while I consider myself the greenie of the house, I'm also the biggest consumer and I bought several items I've never used.

My audit also raised ethical questions about individual responsibility for carbon footprints. Is my child responsible for the things she asks for that I buy? What about mandatory purchases we can't avoid, like school uniforms? Is there a household commons for appliances? What about gifts, do emissions sit with the recipient or the giver?

A sample from my family audit of stuff. Clearly, these are all essential items.

How will I cut back?

Now that I've got a baseline showing where most of the carbon sits, I'll run some experiments to cut back.

- Clothes. Fast fashion, buying second-hand and choosing better.

- Buy less, buy better. I'll road-test ways to reduce impulse spending, buy less stuff and buy stuff that's less carbon-intense.

- Ewaste. While small for me, electronics are a major source of emissions for some. I'll dig into the data and find out how to cut carbon.

- Supermarket trolley. If time allows, I'll audit the non-food contents of my supermarket trolley and work out ways to cut back.

Spreadsheet calculations, data and references in 'Notes' section, Week Thirty-Two. My data is much more rubbery than usual so check out the details if you need a good laugh.