Hi, Bruce here, I thought I should put a more positive spin on our efforts after reading Hilary’s ‘Negative thoughts' post.
The thing I’m feeling positive about is our food. Most carbon calculators only address easily measured and monitored items such as petrol, electricity and gas usage. However, research by Professor Manfred Lenzen of Sydney University, shows that fossils fuels only account for 25 % of our per capita carbon emissions. What about the other 75%?
Professor Lenzen has developed a personal greenhouse gas calculator, from which he calculates that the production, packaging and transport of food causes 20% of our carbon emissions. He identified seven food and one drink category, and allocated a ‘greenhouse price’ per dollar spent to each of these. Beef products have the highest ‘price’ at 8.9 per $ spent, while fruit and vegetables have the lowest at 1.4.
To calculate your food ‘greenhouse’ budget, you need to know your annual expenditure on each of these categories. I did this for a month (March) and extrapolated to get an (approximate) annual figure. I then compared our results with Lenzen’s national averages for each category.
I was appalled to find that our food emissions were 5.2 tonnes — above the national average of 4.9 tonnes. We don’t eat beef, we shop locally, rarely buy imported foods, grow a lot of veggies, buy mainly organic food and don’t over eat, all of which should have lowered our emissions, so how could we be higher than average?
I then remembered that Prof Lenzen’s work was based on 1994/95 prices, and I was using 2007 prices, thus inflating the results (his calculator is currently being updated). Since the CPI has increased by 36.5% since 1995, I adjusted our expenditure for each of the categories, and came up with a revised figure of 3.3 tonnes, well below the national average — what a relief, and something to feel really positive about!
But wait, there’s more. The organic food we buy doesn’t use high-energy inputs such as fertilisers, herbicides and pesticides, so will produce less emissions than non-organic food. This is not factored into the calculator. Also, our low food miles will reduce emissions relative to the national average, so I’m giving us a 10% reduction in emissions for both food miles and organic shopping, which brings our annual food-based emissions down to a mere 2.6 tonnes.
I’ll do another month’s recording and take an average, just to make sure we have got it right, but I’m pleased to report that Hilary cheered up enormously on hearing the results so far.
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