Monday, September 29, 2008

Local production is not necessarily more environmentally sustainable

That’s the conclusion of a recent blurb in Foreign Policy Magazine (not available online). The reason, as was also noted in the NYT last year, is that travel takes up a small percentage (11%) of the total emissions from food production.

This is of course a counter argument to such people as Fred Curtis, who argues for a new field in contrast to ecological economics, which he calls eco-localism. There has also been a huge growth of farmer's markets in the U.S. recently, with undoubtedly many people doing so out of environmental concerns.

When a person faces the choice between eating a locally produced food and one that has traveled from another state or continent, the advantages of local food are not clear cut. Here are three instances when an individual who chooses to focus on consuming local foods is in fact contributing a larger amount of greenhouse gases than if he or she were buying foods imported from another area.

1. Buying local meat could be worse for the environment if the feeds are not local

Producing 1 kg of any kind of meat requires much more than 1 kg of feed, meaning that buying locally produced meat may not be better for the environment if the feed had to be transported. For example, it takes around 7kg of feed to produce 1 kg of beef, while the environmental cost of transporting meat versus feed is not likely to be significantly different (while meat must be refrigerated during transport, the sheer size of the difference of input versus output though still overshadows these differences).

In this case, if the feed is imported from a distance of more than 1/7th the distance a person could have bought the meat from, the effect on the environment is worse. That means a person buying beef in Manhattan from a producer in New York State that uses the most common feeds from the Midwest is in fact impacting the environment more than if they bought the meat from a Midwest producer who uses local feeds.

2. Local meat, even under the best conditions, is still worse than imported fruits and vegetables

In a study of local versus imported food in Washington State, Daniel Morgan, Stephanie Renzi, Richard Cook and Heidi Radenovic found that transporting fruits and vegetables from as far away as New Zealand, Peru and Norway had a significant environmental impact when compared to the impact of local fruits and vegetables, but was 1/20th the environmental impact of eating local fish. Relative to fruits and vegetables the effect is important, but when compared to making locally grown meat, the effect is almost trivial.

3. Which is better, efficiently produced fruit from another continent, or inefficiently produced local fruit?

It’s not always clear. An example of when it’s a bad idea to eat local comes from Lincoln University in New Zealand, who studied the environmental impact of lamb raised in New Zealand and Britain. They find that, even with the huge impact of transporting the lamb, New Zealand is so efficient at producing feeds for the animals that its better to get it flown in.

Morgan et al. are the only ones that I am aware of to look at this question for vegetables. They found that 1/4 pounds of asparagus grown in Yakima, Washington requires 38 grams of CO2 equivalent, while the same amount of asparagus grown in Ica, Peru produces only 17 grams of CO2 equivalent. Transport between the two locations produces 31 grams of CO2 equivalent. While it is still better to buy the locally grown asparagus, the difference in the environmental effect has decreased significantly as the Peruvian asparagus is so much more efficiently produced than Washington asparagus. Given the right conditions then, it is likely that a locally produced food produces more greenhouse gas emissions than an imported food.

What to do?

The answer to all of these dilemma's is well known to economists: internalize the cost of environmental externalities. The reason people would ever buy an environmentally inefficient food is that the true cost of shipping - that is, the economic plus environmental cost of shipping - is not realized by the shipping company. If the full cost was properly internalized, the market would correctly determine who is truly the most efficient producer, both economically and environmentally.

You can also decrease your consumption of environmentally damaging foods, especially meat.


Scarlett Lion said...

Hi Nathan,

Haven't seen you in Uganda for awhile so it's good to see you online at least.

This argument is very interesting - though I wonder, let's assume that buying local produce ups in the average income of a community (which may or may not be true, but sounds like it should be, though I guess economics are often counter-intuitive), then wouldn't all those people who have benefited economically in turn be able to make better/more environmental decisions even if the cost is higher?

Liam de los Reyes said...


Does this study look at the effects of government subsidies on increasing efficiency? If more environmentally-friendly methods are more expensive, do large agribusiness have a head start receiving subsidies from national governments? Or is this directly the result of economies of scale?

Also, how many Midwest meat-producers actually use local feed? That information may be in the study but I have yet to read it. I'd be interested to see a map of primary corn/feed production and primary cattle production.