Blog

Deck the hall with boughs of holly (unless holly doesn't grow where you live)

Today Forbes.com published a piece I wrote with Henry Miller, who is a fellow at the the Hoover Institute at Stanford University.  The piece is on local foods, and now (in the winter, at Christmas) is perhaps one of the best times to think through the logic of locavorism.  

Here are a few snippets from the beginning:

The Christmas season brings visions of candy canes, cider and sugar plums dancing in the head.  Unless, that is, you’re a committed locavore who has scorned peppermint, sugar beets and apples, because they’re not found in your neck of the woods in the summertime, much less the dead of winter.
The desire to help out a neighbor or even a local farmer can be a noble one, especially in this gift-giving season, but sentiment shouldn’t keep us from thinking critically about the consequences of forcing municipal hospitals, schools and other institutions to source an arbitrary percentage of their food locally.

and the end:

If we are to live by the locavore’s mantra that we will consume only what can be made locally, we had better board up our chimneys on Christmas Eve.  No matter how magical are his reindeer or how benevolent his elves, we daren’t accept Santa’s wares because, well, the vast majority of them are made far away.  No self-respecting locavore would be caught dead sucking on a candy cane made at the North Pole.
Yet, St. Nick is a good guy and deserves our respect and patronage as much anyone else.  The same goes for our local farmers.  If we trust our local farmer to give us what we want and you do the same, then surely we can trust your local farmer too.  And your local farmer is probably better at growing some things than ours.  So as we send holiday greetings to dear friends far and wide, let’s not demonize those who want to do the same with food

What are the Environmental Costs of Moving Toward Lower Yielding Cropping Systems?

Here are the conclusions from an article just published online in the American Journal of Agricultural Economics

Crop yield development will play a critical role in future land use dynamics. Indeed, it will determine the requirements for additional cropland, and also have a strong impact on grassland expansion. We have illustrated that compared with yield stagnation, maintaining past trends in crop yield growth would save 290 Mha of cropland and avoid additional expansion of about 120 Mha of grassland by 2030. Our results suggest that failing to take into account the effects of livestock sector dynamics and the corresponding grassland requirements when assessing the effect on land sparing of increasing crop yield may lead to significant inaccuracy–a difference of 17% in our example.
With respect to GHG emissions, we show that by 2030 these would be lower by more than 2 GtCO2-eq per year if crop yields grew according to the past trends as compared to yield stagnation. Crop yield growth also seems to be a cost efficient way of abating GHGs, as the estimated R&D cost involved would be about U.S. $25 per tCO2-eq, while the marginal cost of reaching this target with stagnating yields would be U.S. $75 per tCO2-eq. However, to be effective as a mitigation option, crop yield increases need to be accompanied by policies that prevent further expansion of consumption in rich countries in order to avoid the potential rebound effects illustrated by Choi et al. (2011).
Overall, policies and investments targeting crop yield enhancement should be an important priority for the future of agricultural development (Herrero et al. 2010). Such measures could help to fight food insecurity, while at the same time contributing to climate change mitigation at a cost that is competitive with other mitigation strategies.

Assorted Links

  • I find it hard to take some of this writing seriously, but here is an interesting take on obesity “informed by feminist poststructuralist theory” which argues, among other things that:
Obesity science qualifies as ‘state science,’ to use Foucault’s term: it is a tangled web of government lobbies, academia and its research sponsors, service industries from the human genome sciences to multinational pharmaceutical and agribusiness complexes, the legal-juridical complex, and the insurance industry. Obesity science and its hegemonic norms have instituted a hidden political agenda through the very language and technologies deployed in the name of ‘truth.’ Obesity science and its dominant discourse act as a ‘fascist structure’

Efficacy of Fat Taxes and Thin Subsidies

Science News reported the following results from a recent study:

Taxes on soft drinks and foods high in saturated fats and subsidies for fruit and vegetables could lead to beneficial dietary changes and potentially improve health, according to a study by experts from New Zealand published in this week's PLOS Medicine.

and

The authors say: "Based on modelling studies, taxes on carbonated drinks and saturated fat and subsidies on fruits and vegetables are associated with beneficial dietary change, with the potential for improved health. "

My first reaction was "duh."  Clearly if you raise prices of (say sugar or fat) high enough, you will get people to eat less.  In fact, one way researchers often model a ban on a substance is by simulating what happens when the price gets high enough that no one buys the product.  

Thus, the key question isn't whether one can change consumption and nutrient intake with sufficiently high taxes or subsidies.  The better questions are by how much? and at what cost?  An even better question still: where is the market failure that would justify the tax or subsidy?  The answer to that last question is actually much less obvious than most public health professionals presume (see here or here).

On the former question of how much?, let's turn to the original study mentioned at the first of this post.  The study is actually a literature review, pulling together the findings of previously published papers (including one that I co-authored).  Below is a graph showing some of the key results from different studies simulating how much change in consumption (or energy intake) would occur from a change in the price of a good. Pay attention to the scale of the vertical axis.  My take (see the middle chart) is that it would take very large price changes to get energy consumption to change by much (a 20-40% increase in price results in a 0.2-0.4% reduction in calories consumed).  

Stated differently, these sorts of policies are likely very costly in achieving the desired health outcomes.  Moreover, we must ask why - if these health changes are really so inexpensive and beneficial - people are not already voluntarily making them?

fattaxelasticities.JPG