The Economist takes a look at Carbon Labeling and some of its issues.
But calculating the carbon footprint of a product is far from easy. Unlike the fat or sugar content, it cannot be measured directly. For a start, how far back up the supply chain do you go? Academic “life-cycle analyses” go into painstaking detail, factoring in the emissions associated with building factories in which food is produced, for example. But doing this for thousands of products would be a mammoth undertaking. The trick, says Mr Murray, is to find the right trade-off between rigour and a methodology that works across thousands of items. The Carbon Trust's approach is to include carbon dioxide produced in the manufacturing but not, say, that from employees commuting to work.I think that is true that it will be a massive undertaking, but once you have collected values for many of the underlying inputs to products, then calculating for a new product will not be that difficult.
How far down the supply chain do you go? The Carbon Trust's labels aim to show the carbon emissions associated with making something, packaging it, getting it to the store and disposing of it. Because bags of crisps delivered to far-flung shops will have travelled farther from the factory, the auditors use an average figure for transport emissions. Similarly, national averages feed into calculations of whether a product or its packaging are recycled, incinerated or put into landfill.Interesting points on boiling potatoes and shampoo.
The labels do not count the energy needed for refrigeration, lighting and heating in shops. Nor do they include the emissions that come from using a product. The carbon footprint of boiled potatoes, for example, is dominated by the emissions associated with cooking them. Whether you put a lid on the pan can make more of a difference than how they were farmed, or whether they were produced locally or not. Similarly, the emissions of shampoo depend on how long you spend in the shower, how hot the water is and the quality of your boiler. Such things cannot be captured in a carbon label, so they are not included, says Mr Murray.
I think that adding carbon labels is a good thing to do, as emissions caused by our personal use of gasoline, natural gas and electricity only account for around 1/3 of our total emissions. The other 2/3 are embedded in the products that we purchase. Currently there is no way for educated consumers to figure out where that 2/3 comes from. If you add labels, then you could figure it out for yourself, and be able to shift your consumption to "low-carbon" products.
I also think that the improving the labels will be an evolutionary process. The first ones released will probably not be all that accurate, but hopefully in ten years time they will be pretty good.
via The Economist