Sunday, February 21, 2010

What You Can’t Measure, You Can’t Control

The commitment made by 10:10 members is to reduce their carbon footprint by 10% in 2010. This is a very small fraction of the 80% reduction we are told we need to stop global warming so surely it should be possible? But is it so easy? To answer this question we need to apply science, not emotion.
There has been a huge rise in obesity over the last 40 years. Scientists have been looking into this to try to understand why. Most people intuitively link it to the rise in processed “fast” food consumed at home and in restaurants but scientists have found that our daily calorie intake has not significantly changed in the last 40 years. They did, however find a strong correlation between obesity and car ownership. Moreover, the increasing use of cars has led to the demise of the corner shop and replacement with out of town supermarkets such that it is now almost essential to own a car. If it is lifestyle change that is causing the rise in obesity and not our calorie intake, it’s no wonder that most diets don’t work.

We should conclude that a “carbon diet”, like any other diet, will only work if we make significant and permanent lifestyle changes.  Unfortunately as any dieter knows, those diets that include [perceived] depravation or take significant physical or mental effort are very difficult to stick to.  Currently the UK Government is urging its populous to drive “5 miles less per week”.  While the aim is laudable we first should ask “5 miles less than what?”; i.e. how do we know if we are doing it? Counting miles is like counting calories; it’s too hard to do so it won’t work for the majority of us.  Secondly there is an implicit assumption that many journeys are simply not necessary. For most of us going to work, going shopping etc are necessities.  In reality the car is a means to an end, not an end in itself and to affect a cure you have to tackle the disease, not just the symptoms. For instance, according to my brother in law, Professor Gareth Edwards-Jones, half of all so called “food miles” are down to car journeys to and from superstores.  Perhaps the Government should be promoting on-line grocery shopping as a concrete way of saving a trip to the superstore rather than some vague, inaccessible (because it is not measurable) 5 miles per week?

But surely there is a quick fix? Wind energy, solar energy and other renewable energy sources are all laudable goals to pursue but it’s not clear to me whether the whole life-cycle [carbon] costs of some of the proposals are actually higher than the ones they replace. Take the Government car scrappage schemes for instance. While it is clear that new cars produce much less carbon per mile than older ones, how much carbon is produced in making that new car? and how many years could you run the old car on the equivalent carbon saving? Let’s assume that the carbon cost of producing the new car is the equivalent of 1 years fuel consumption.  I have no idea whether this is correct but it sounds reasonable.  Let’s further assume that the new car produces 25% less carbon per kilometer than the old one.  The break even point of the new car would then be after 3 years, by which time the old car would be 13 years old and would probably be scrapped anyway.  I suggest that the car scrappage scheme was more about helping the economy than reducing our collective carbon footprint.

Low energy light bulbs are a clear win-win but even here the actual carbon saving is hard to measure.  According to a BBC article lighting accounts for 19% of global electricity generation, though it does not cite a source. Other sources more targeted towards domestic electricity consumption put this figure closer to 10%.  A quick web search would show that electricity makes up only 16% of the total energy consumed in an average European home.  The consumption of energy in the home is roughly 2x that consumed by the family car(s).  Low energy bulbs save around 75% of electricity.  Replacing all lights with low energy lights would therefore result in a total carbon saving of 10% * 16% * 2/3 * 3/4 = 0.8%, a worthwhile saving, but hardly a magic bullet.  Perhaps less well known is that you could save as much energy by changing your 10+ year old refrigerator to a modern A+ rated one, or even changing your 20 year old central heating pump for a new one.  It is these things, thac consume power 24/7, that are the real electricity hogs.

While many of us know fad diets are doomed to failure, the lack of published (or should I say publicized) science about carbon reduction leaves many of us clutching at straws.  There is a clear need to lower our carbon footprints, what is less clear is how we can achieve it.  We need tools to measure, not Government platitudes if we are to make lasting, positive lifestyle changes. This to me should be the central lobbying effort within 10:10.

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