Carbon Footprint Eco Label

The emphasis at the moment in the UK is on carbon foot printing. But what is a carbon foot print?

The label above shows a value of 100g but how did they arrive at that figure?

Say you go to the shop and buy a carrot. In order to calculate the carbon foot print of that carrot, you have to calculate the embodied carbon, that is the amount of carbon that was released during the manufacture (in this case the growing and transport and storage) of that product.

1. The Seed was this dried using gas heating, stored in a refrigerated building did it have packaging? How much Carbon per Carrot?
2. Planting how much diesel did the farmer burn in his tractor sowing the seed? How much Carbon per Carrot?
3. Fertilizer + Pesticide (if non organic), how much energy was used to produce these? How much Carbon per Carrot?
4. Growing was there any heating? How much Carbon per Carrot?
5. Harvesting, diesel burnt, % of machinery worn out during the harvest? How much Carbon per Carrot?
6. Transport, to storage the further you go the more diesel burnt. How much Carbon per Carrot?
7. Storage. Refrigeration etc rotation of stock use of electricity. How much Carbon per Carrot?
8. Waste Disposal. How much Carbon per Carrot?

So you add up all these values and get a figure and that gets you your embodied carbon figure. In doing the calculation for a carrot I would have to speak to:

1. The seed producer
2. The Farmer, or perhaps a separate contractor.
3. Fertilizer manufacturers.
4. Haulage contractors.
5. Storage depot.
6. Waste Management Contractor

It will take each of these groups time to find the data I need. So now imagine if I wanted to do the same for carrot and coriander soup, still a simple product. But now it will have a carton (where did the wood come from?, also the plastic lid and lining if the carton), herbs and spices where did these originate from? Plus the cooking preparation etc and extra storage and transport. You can expect the above lists do double perhaps triple in size.

This process is based on LCA (Life Cycle Analysis) where by you break down a product and investigate each of those components for its impact, it is a good way to make processes more efficient. For instance when looking at the LCA of a carrot you may decide that the storage uses a lot of energy (carbon dioxide is released during the generation of electricity), so you could improve on this portion of the carbon footprint by swapping fossil derived energy for biomass derived energy.

So it is hoped that on entering a supermarket the consumer will look at two bags of carrots, and choose the one with the lower value (measured in grams), there fore the producer with the less environmentally friendly carrots will have to up his game or go out of business.

The diagram to the left shows how each stage of manufacture, trans port and disposal might account for the total emissions of a product. Before viewing these figures you may have considered the distribution to be the most carbon intensive part of the process, but in fact it is the farming. Which has the cuddliest image of all!

The graph to the left shows the embodied carbon values for three type of potatoes. They all have similar carbon foot prints (Organic baby new potatoes being the lowest at 140g), but look at the percentages . . .  in use (light blue) which for a potato is cooking! the King Edwards produce significantly more carbon than the baby potatoes, this is probably due to the fact that the baby potatoes cook quicker due to a proportionatly large surface area. So if you were to eat them raw the King Edwards would be the green option!

The Carbon trust have a lot of guidelines on this sort of thing please click on the link to investigate.

www.carbontrust.co.uk/publications/publicationdetail?productid=CTV033

Or you can look at the Wikipedia page for Carbon Footprint:

http://en.wikipedia.org/wiki/Carbon_footprint