3 Virtual oil
There may be those amongst you who have used no powered transport at all in the last week - perhaps you cycled, walked or ran everywhere you needed to go, or even rode a horse. However, in the developed world, even individuals who don't personally use powered transport live lives that rely heavily on oil. Almost everything we buy has been produced by a process that consumes oil - it all contains what might be called 'virtual oil'.
Think firstly about the food we eat. Diets in the developed world rely on the cheap transport we get from oil. This applies whether we are eating intensively reared meat flown from the other side of the world or 'organically' grown vegetables driven from 30 kilometres away. Clearly there can be vast differences in the amount of oil consumed in bringing different foodstuffs to us, depending both on the distance travelled and the type of transport used.
In the past, campaigners in the UK have used the concept of 'food miles' to try to capture the differences in the quantities of oil consumed to get different goods to us - their focus was on making consumers aware of the greenhouse gas emissions involved (see Section 7 for more on this). The 'food miles' associated with an item of food measures the distance from the point at which the food was produced to the point at which it is consumed, but the concept has since come under criticism as too simplistic.
For UK 'environmentally engaged' consumers shopping in spring, tomatoes grown in southern Spain might be preferable to home-grown tomatoes - despite the fact that the Spanish tomatoes have many more food miles attached to them. Why might this be true?
The UK-grown tomatoes would have to be grown in heated glasshouses, which could easily involve the consumption of more energy (and the emission of more greenhouse gases) than that required to transport tomatoes from Spain, where they could be grown outdoors or in unheated glasshouses.
Whilst the greenhouse gas emissions resulting from transport are an important part of the environmental impact of the things we buy, it's important to take into account the emissions involved in every stage of an object's production and use. In more recent years, campaigners have tended to use the concept of a 'carbon footprint' - an estimate of the total impact a product has on anthropogenic global warming. It is an area where there are often no clear-cut answers, and differing estimates of environmental impact can often lead to controversy.
The use of oil-based transport makes an almost invisible contribution to the manufacture of all modern goods. I own a cotton jacket (Figure 3) whose label tells me that it was manufactured in Romania. It is immediately apparent that oil will have been used to transport the jacket from Romania to the shop in Manchester where I purchased it (there were probably a few stops along the way). Cotton is not a crop that is grown commercially in Romania, so the cotton will have been imported into Romania from another country - perhaps Egypt or China. This too will have involved the consumption of oil.
The deceptively simple jacket is an amalgam of different parts manufactured all over the world. It has a lining made from polyester and viscose - two different synthetic materials which are likely to have been manufactured at different sites. It has plastic buttons and is held together by cotton threads. The cloth has been dyed an attractive olive colour - the dye will have been manufactured at one site and transported some distance to the factory that dyed the cloth.
The manufacture of the jacket is only possible because cheap transport fuelled by oil allows the manufacturer to assemble all the parts needed. This relatively complex process of bringing together parts from all over the world applies to almost all the goods around us in our homes. You have explored the manufacture of a jacket - but think of how many more parts and materials have to be produced separately and brought together to manufacture a complex object like a television or computer.
It is very difficult to state accurately how much of an individual's daily crude oil consumption is taken up by the 'virtual oil' in the goods they use. However, you can make a rough estimate. According to International Energy Authority statistics, approximately 61% of crude oil consumed is used for transport (this includes both personal transport and the transport of goods), and you have estimated that on average each individual in the UK is responsible for the consumption of 4 litres of crude oil.
Use these figures to estimate the total daily volume of crude oil that, on average, is used for transport for each individual in the UK.
If 61% of crude oil is used internationally for transport, you can estimate that each individual in the UK consumes an average of approximately 4 litres × (61/100) = 2.4 litres per person for transport alone.
This estimate of a daily consumption of 2.4 litres of crude oil for transport includes both the personal and public transport discussed in Section 2 and the 'virtual' crude oil in the goods and food used by each individual.
Most crude oil is ultimately used as fuel - so while in the UK a person might on average use 2.4 litres of their 4 litre allocation for transport in all its forms, a further 1.1 litres are used as fuel to provide energy for activities other than transport - this includes domestic heating fuel, and fuels for industrial and agricultural processes.