As it happens there has been a lot of talk about food miles lately. At first blush food miles are an excellent shorthand for calculating a food product's carbon footprint. Then along comes a somewhat controversial article in the February 2008 New Yorker by Michael Specter that was recently seconded by Slate Magazine (also see my recent article in The Shuttle - PDF download). Turns out that lots of assumptions we make about food miles as a proxy for carbon footprints are wrong. If you run the numbers, it turns out that the mode of transport is just as important as the distance traveled (airfreight is worst, then refrigerated diesel trucks, then seafreight and so on). As Specter puts it:
[T]he relationship between food miles and their carbon footprint is not nearly as clear as it might seem. That is often true even when the environmental impact of shipping goods by air is taken into consideration. "People should stop talking about food miles," Adrian Williams told me. "It's a foolish concept: provincial, damaging, and simplistic." Williams is an agricultural researcher in the Natural Resources Department of Cranfield University, in England. He has been commissioned by the British government to analyze the relative environmental impacts of a number of foods. "The idea that a product travels a certain distance and is therefore worse than one you raised nearby - well, it's just idiotic," he said. "It doesn't take into consideration the land use, the type of transportation, the weather, or even the season. Potatoes you buy in winter, of course, have a far higher environmental ticket than if you were to buy them in August." Williams pointed out that when people talk about global warming they usually speak only about carbon dioxide. Making milk or meat contributes less CO2 to the atmosphere than building a house or making a washing machine. But the animals produce methane and nitrous oxide, and those are greenhouse gases, too. "This is not an equation like the number of calories or even the cost of a product," he said. "There is no one number that works."Oh well.
No wonder a new study out of the UK shows that most people who believe themselves to be living green actually have large carbon footprints (it's all that air travel). This stuff is hard to figure out.
Just take a look at a June issue of Wired magazine that featured a big "Face on you" (as we used to say circa 1979) to the environmental movement. According to Wired, you should love your ten-year-old Tercel and your local nuclear power plant and hate your Prius, organic food, the spotted owl and every other favored symbol of the green movement.
It's a bit, um, overstated, but their main point is that saving the planet is all about reducing carbon full stop so forget everything else. As over the top as the story is, they're probably more right than wrong. Nationally and globally, it WILL become all about carbon reduction as far as the environment is concerned. Everything else WILL fall to the wayside. It's not like the spotted owl has been the historic driver of the national environmental debate.
A political scientist of my acquaintance opined recently that if you take the politics of carbon reduction into account, then it's clear that nuclear power is going to come back in a big big way. It will be the new ethanol (which in the end didn't really work out so well but that's another story), i.e. nuclear power will become every politician's favorite answer to the carbon problem. Just ask John McCain. After all, it's not like we're going to reduce ENERGY use 90%. We need to run our plasma tvs, air conditioners and plug-in hybrids on something...
Anyway, there are definitely some good bits in the Wired issue. It points out the problematic aspect to hybrids - producing their nickel-based batteries is about as dirty and carbon intensive a process as there is. According to Wired, every new Prius comes with a significant fuel "debt" to be paid down. It's a bit of a tricky calculation since ALL cars come with a debt - it takes carbon to make any car - and it's unclear what standard they're using to measure it. But the point that hybrids aren't as clean as they seem is valid.
Also, they talk about how air conditioning isn't really as bad as you might think, at least compared to heating a house through a Northeastern winter. Again, their numbers are eye-opening. It does assuage the guilt a bit to know that cooling a house in summer takes 1/8 the energy of heating it in winter. But what Wired doesn't mention is that the refrigerant used in US air conditioners is 1700 times more potent as a greenhouse gas than carbon. And all that refrigerant has to be disposed of somehow. There's always something...
And even if you agree that A/C has its positives, that doesn't excuse the businesses all over the country that keep their thermostats at 68 degrees in the summer. That's just wrong and crazy and why doesn't anyone STOP THEM!!
Where was I? Oh, yes. Saving the planet is a tricky business. The law of untended consequences seems to be only one in force as far as carbon goes. But then, "unintended consequences" is what global warming is all about, isn't it? Suffice it to say, I haven't figured out the secrets to a low-carbon lifestyle just yet (short of that cave in Canada I have a downpayment on). But as I come up with them, I'll surely list them here. So come back soon.