Sitting on a beach in Italy with my family leads to all sorts of bizarre conversational directions. My 15 year old son and I were filling some time by challenging each other to estimate things based on scant information and assumptions. Having just figured out that the volume of the ocean was some 1.4×10^21 litres (we were surprisingly close as it turned out) we turned our attention to the number of boxes of Cornflakes sold in the UK each week (yes, this is going somewhere).
Assuming a population of some 60 million of whom 60% eat breakfast cereal and of those 10% eat Cornflakes, we ended up with 3.6 million servings a day. If an average box lasts 10 days then that comes to some 2.5 million boxes per week.
The next challenge was to estimate how much energy is used in just moving Cornflakes from the point of production to the point of purchase in the UK. We started by assuming that an average distribution truck (accounting for both big supermarket and smaller shop distribution) would have a capacity of 4 x 2 x 2 metres or 16 m3. If a box is 40 x 25 x 7 cms or 7000 cm3 then a truck could carry about 2000 boxes. That means 1200 truck loads of Cornflakes per week.
We then assumed that on average a purchase point is no more than 100 miles from a production point so that the average box of Cornflakes travels 50 miles at a minimum (I suspect it may be somewhat higher than this). If an average truck gets 10 miles per gallon then moving Cornflakes in the UK consumes 6000 gallons of fuel per week or about 150 barrels of oil (about 10p for each customer per year). That adds up to some 8000 barrels per annum which in turn adds nearly 3000 tonnes of CO2 to the atmosphere.
None of this may sound much, but don’t forget that we are just moving Cornflakes (no other cereal) from the point of production to the point of purchase in the UK only ! One tiny aspect of our lives.
Food for thought !