The WWF (World Wildlife Fund) has a nice page to calculate your personal CO2 – footprint. The result is given as the number of earths required to satisfy your lifestyle if all people on the planet would live like you.
The methodology seems far from being exact. It is more of a marketing tool to raise environmental consciousness but it does not give you any rule of thumb regarding your personal consumption style. I had a result of 1.99 earths and I felt rather dissatisfied with the actual information given (Searching on the german web page I found a very informative glossary here).
This raises the question: how much do particular acts of everyday consumption contribute to be destructive / substainable on a collective and long-term scale? The main issue here is to get to know the details of overall resource consumption broken down to single products. And the result has to be put in relation to a substainable per capita budget for greenhouse gas emissions.
Blueberries from Peru
Let’s do a more or less complete example with a small box of Blueberries sold for 1.19 € per 125 g in a supermarket nearby.
| emission source | CO2 – emission |
| Production / ground transport Peru | not calculated |
| Air transportation Peru – Germany | 2,08 kg |
| Calculation: Distance Lima, Peru -> Frankfurt, Germany: 10,730 km (6.668 miles) linear, est. flight distance 11,265 km (7,000 miles). Example freight carrier: Boeing 747-400F. Max. fuel capacity: 173.472 kg, Max Range: 9.200 km. Fuel consumption per km = 18,86 kg. Max Freight Load is 112 tons (= 902.080 packs of blueberries). Overall fuel consumption is 212.400 kg, resulting in 670.000 kg of CO2 emission. |
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| Ground transport Germany | 0,008 kg |
| Calculation with 10 ton truck: Avg. fuel consumption per 100km = 35 l. Avg. Distance (2-way) from airport to supermarket: 500km. Total fuel consumption = 175 l. CO2 emission over assumed distance: 642 kg. Freight load allows to transport 80.000 packs of blueberries. |
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The only factor which matters here is transportation as air freight. Two kilos of CO2 emissions – that doesn’t sound much. To correctly judge that singular emission we have to scale it out collectively and in time.
Global impact
Suppose you buy 1 kg of oversea fruits each week. This means an overall emission of 15 – 20 kg CO2 per week and 780 – 1040 kg per year. Given 39,9 million households in Germany (source: Destatis, 2013) and an assumed 20 million households buying 1 kg of fruits every week this individual consumption mounts up to 15,6 – 20,8 million tons of CO2 emission each year.
What is a sustainable per capita CO2 budget?
To correctly judge the effects of this singular act of consumption on my overall CO2 budget I needed to know more about sustainable per capita emissions of greenhouse gases. My research led to the the following data table:
| 2013 | 1970 | Source | |
| World population (in million people) |
7.162 | 3.691 | Geohive |
| Global CO2 emissions (in million tons) |
36.131 | 14.850 | CO2 Information Analysis Center |
| CO2 emissions (in tons per capita) |
5,045 | 4,023 |
The CO2 – footprint on the WWF website conforms pretty well to this calculation. According to WWF I am individually causing 10,5 tons of CO2 emission per year – so WWF calculates with 5,2 tons of CO2 emission per capita (~ 1 earth for all).
If we assume that the point of no return – where we could fully counteract the effects of anthropogenic emissions on climate change – was in 1970, then an individual profile of around 4 tons of CO2 would be an environmentally safe footprint today.
My weekly imported fruit bowl would already contribute 1/4 to this sustainable budget. And that’s just the blueberries.
tldr; If you want to live a sustainable lifestyle and preserve the planet for your children, never buy fruit from overseas ( (flown in).
Links:
Umweltökonomische Gesamtrechnung des Statistischen Bundesamtes
WWF – Glossar zum Co2 – Rechner (pdf)