Tyler Cowen points us to this report from Ezra Klein:
…two Carnegie Mellon researchers recently broke down the carbon footprint of foods, and their findings were a bit surprising. 83 percent of emissions came from the growth and production of the food itself. Only 11 percent came from transportation, and even then, only 4 percent came from the transportation between grower and seller (which is the part that eating local helps cut).
Cowen adds,
In other words, when it comes to food the greenest things you can do, if that is your standard, is to eat less meat and have fewer kids.
I’m reminded of a recent New Yorker article by Michael Specter. In it, he interviews John Murlis, the chief scientific adviser to the Carbon Neutral Company:
Murlis worries that in our collective rush to make choices that display personal virtue we may be losing sight of the larger problem. “Would a carbon label on every product help us?” he asked. “I wonder.
You can feel very good about the organic potatoes you buy from a farm near your home, but half the emissions—and half the footprint—from those potatoes could come from the energy you use to cook them. If you leave the lid off, boil them at a high heat, and then mash your potatoes, from a carbon standpoint you might as well drive to McDonald’s and spend your money buying an order of French fries.”
The basic premise of the article is that reducing carbon emissions is more complex than “buy local”.
“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.
Specter also suggest that growing certain types of foods in distant places–even New Zealand–might be more efficient from a carbon perspective. Take this example–a study of the environmental costs of buying roses from Holland versus those airlifted from Kenya:
In each case, the team made a complete life-cycle analysis of twelve thousand rose stems for sale in February—in which all the variables, from seeds to store, were taken into consideration.
They even multiplied the CO2 emissions for the air-freighted Kenyan roses by a factor of nearly three, to account for the increased effect of burning fuel at a high altitude. Nonetheless, the carbon footprint of the roses from Holland—which are almost always grown in a heated greenhouse—was six times the footprint of those shipped from Kenya.
It’s an interesting prospect: could increased food trade with more sun-kissed nations reduce carbon emissions and poverty at the same time?
The full article is worth a read.
5 Responses
I believe the point would be that every new step of mechanization in industry and other production processes requires energy, and today most of that energy is coming from GHG emitting processes. Hence, the level of mechanization in the production process has a larger impact on GHG emissions than transport.
And when it comes to meat, cattle, sheep, and other animals raised solely on pastures or in wild environments has completely different GHG than the same animals raised on manufactured animalfeed in heated (or cooled) buildings. Actually so much more energy is spent in this production process, that transport, also here, becomes less relevant than it otherwise would.
So which conclusions can we draw from this? Well, there are two responses that are “sustainable” in the long run:
1. Reduce energy consumption in manufacturing and other production.
2. Rely on some completely different source of energy.
Solution #1 would most likely mean a massive reduction in living standards around the world, thus it constitutes a social challenge.
Solution #2 appears to be possible with technological progress, but that technology won’t be invented until it is profitable to do so.
So what to do in the mean time? Well, we have the classic toolbox: Subsidize research, and tax GHG emitting technology. Yet politicians, worried about their short-time voter ratings, do the opposite: Fight for cheaper gasoline and put money into bio-fuels rather than any comprehensive research.
It’d be a mistake to conclude that food miles are an entirely useless concept. The Weber and Matthews paper (the Carnegie Mellon study to which you refer) shows that the choice to eat grain-fed meat has a much larger impact on GHG emissions than the choice to transport food long distances. Transportation is still an issue. The energy and GHG inefficiency of our animal production is simply a far greater issue.
In Norway we like to brag about oyur organix tomatoes, and use them as an excuse to halt imports of tomatoes as much as possible. It is supposed to be more environmentally friendly. The problem is, however, that greenhouse tomatoes from Norway consumes so much energy that you could send them almost all the way around the earth with an airplane, one tomato pr seat.
Not only tomatoes, however, are problematic. As environmentalist Axel Nærstad just pointed out for me, sending Norwegian fish to China for fileting, and then back again, reduces total carbon emissions, even when you consider the fact that the fish has to be transported in a frozen state…
So much for the “buy local” mantra!
Considering how much time and effort American foodies have spent trying to get their local stores to carry more than potatoes and ketchup, it seems very ironic that the new mantra is “eat local!”. I live in Southern California, so I’m not fussed, but is my mother in South Dakota to forgo grapefruit just because it’s not a local crop?
And eating beef isn’t the problem–if you eat only grassfed beef. Feedlots are bad, not cows.
Its funny that you mention this issue now as I have just finished an edit of an article for Ecological Economics on the ecological footprint. In it I argue that the footprint is NOT a useful tool for understanding sustainability. It sounds nice, but it falls short on a number of important points.
I have also done a little work on the local/import issue. Local really isn’t that much better in some cases.
The answer I give is similar to most other economists: the solution is proper taxation of carbon. Paying the right social price is more important.
Of course, to get even more specific on the issue, I also have an article out at JEEM on subsidies in meat production. Not only is it the biggest carbon footprint of our diets, but we subsidize it in the US!