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There is nothing better than oatmeal soaked overnight with water, lots of spices, honey ,lemon juice, seeds, nuts, cranberries, and … a fruity component. The latter brings me to the topic of today’s blog post: Should I switch from apples to (deep frozen) berries during summer each year to improve on my carbon footprint? I thought, well, cooled storage of apples might take over in terms of CO2eq eventually. It turns out: No.
Here are the numbers
Poore et al. present in Science1 (Fig. 1F):
- 1-3 kg CO2eq per kg berries,
- ~0.5 kg CO2eq per kg apples.
However, I am not sure what is included in these values. In particular, contribution of storage is unclear.
Other studies2 consider 6 months of storage for apples and arrive at values 4-7 MJ / kg. If we consider the German emission factor for 20193, 400 g CO2 / kWh, and substitute 1kWh = 3.6 MJ, we get to values
- ~0.4-0.8 kg CO2 per kg apples,
which is still below the one for berries. However, there is not a huge difference. It might be that seasonal, local berries can beat the stored apples in some cases. The deep frozen ones probably won’t4.
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Poore, J., & Nemecek, T. (2018). Reducing food’s environmental impacts through producers and consumers. Science, 360(6392), 987–992. https://doi.org/10.1126/science.aaq0216 ↩︎
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Slides by INRES institute at University Bonn: https://www.hortigate.de/bericht?nr=54621 ↩︎
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https://www.umweltbundesamt.de/presse/pressemitteilungen/bilanz-2019-co2-emissionen-pro-kilowattstunde-strom ↩︎
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The company Frosta estimates a value for deep frozen raspberries of ~1.5 kg CO2e / kg berries; https://www.frosta.de/fileadmin/content_media/PDFs/PCF-OBST-141011.pdf ↩︎