By Mary Morgan-Richards
Every year, in the lead up to Anzac day (25th April) when Australians and New Zealanders remember all those who died at war, we bake and eat sweet biscuits associated with WWI.
After 100 years I wanted to calculate the impact of my biscuits on global warming. Each ingredient needs to be harvested, prepared and packaged before transporting to my local shop. What is the carbon footprint of these activities? Because food is grown in different parts of the world, I wanted a New Zealand figure. I found a thesis by M.J. Drew from the University of Otago called “Healthy & Climate-friendly eating patterns for New Zealand” and it had all the information I wanted (Drew et al. 2020).
The Anzac biscuit has been described as a culinary icon embedded in the Australian and New Zealand intangible cultural heritage (Cobley 2016) – but it is also a sweet and crunchy treat. The name “ANZAC” first appeared in recipe books during the First World War and what is now known as the Anzac biscuit seems to have emerged independently in kitchens in New Zealand and Australia ~1918 using the same basic ingredients that were readily available at the time (Leach 2008).
Method: Heat water in bowl in microwave on high (about 40sec at 800-1000 watts), add baking soda, honey, golden syrup, oil and stir. Add oats, flour, coconut, sugar and two good pinches of salt. Mix thoroughly. Dust baking try with flour. Place teaspoonfuls of mixture onto the tray. Bake 180oC for about 10 mins until biscuits have melted flat and are golden brown. Allow to cool slightly before removing from tray onto a rack. Eat with a hot cup of tea.
For each food item, farming and processing produces most of the greenhouse gasses (with a few exceptions; Figure 1). Other stages in what is called the “lifecycle” of the food such as packaging, transport, refrigeration all contribute a smaller proportion of emissions per item, but it adds up.
For some ingredients and many recipes there are a range of possibilities; one could use butter or margarine, apples or oranges. If I use canola oil in my biscuits instead of butter, I make the biggest difference to the total footprint. Most canola oil on my supermarket shelf is from rapeseed plants that were not grown in New Zealand, but there are a few yellow fields of rapeseed (Brassica napus) grown, harvested and pressed for oil in this country (e.g. Pure oil NZ). Even though transport is a much bigger contributor to the total for the canola oil I used (about 50%; Figure 1), growing a plant (rapeseed) produces much less CO2 than dairy farming. Butter also needs refrigerating. But without butter I need to add a pinch of salt to my biscuits. Per kg salt has a fairly high emission level and I wonder if we could reduce how far salt needs to travel? – selecting locally produced brands would help (I didn’t need to use pink salt from the Himalayas to get the taste I wanted and I made sure to reduce my chance of suffering from goitre by using a salt with iodine added).
I was surprised to discover that honey production has a lower footprint than either salt or sugar or golden syrup – although more CO2 is invested in packaging honey, the transport and production releases less CO2 in total. But honey is expensive, and it doesn’t easily convert into the same volume of sugar in a recipe. Here I have reduced the golden syrup and sugar a bit, and added honey, but traditional Anzac biscuit recipes (from 1920’s) all have golden syrup. In fact, I might be breaching the NZ law if I don’t have enough golden syrup, as the law here requires that the name ‘Anzac’ is only associated with the original basic recipe (and that they are never referred to as cookies). In addition, completely replacing sugar and golden syrup with honey risks ‘food waste’ by producing a softer biscuit that doesn’t get eaten, so I’ve tried to balance emission-reduction with taste.
Electricity in New Zealand can be completely renewable and so I brought my electricity for baking my biscuits from ecotricity.
In general, vegetables, fruits and whole grains are less climate-polluting (1.2−1.8 kgCO2e/kg) than animal-based foods (12−21 kgCO2e/kg). Potentially I could reduce my CO2 emissions by up to 42%, depending how much I reduce meat and dairy from my diet and continue to minimise food waste – I might even live longer!
Cobley, J. 2016. Should we safeguard ‘the idea of the Anzac biscuit recipe’? Women’s Studies Journal, 30 (1): 62-70. ISSN 1173-6615
Drew, M. J. 2017. Healthy & Climate-friendly eating patterns for New Zealand. University of Otago. https://ourarchive.otago.ac.nz/handle/10523/8058
Drew, J. Cleghorn, C. Macmillan, A. Mizdrak, A. 2020. Healthy and climate-friendly eating patterns in the New Zealand context. Environmental Health Perspective 128(1) https://doi.org/10.1289/EHP5996.
Leach, H. 2008. The pavlova story: A slice of New Zealand’s culinary history. Dunedin, New Zealand: Otago University Press.