Blog

Diet quality, environmental impacts, and food waste

A few years ago when the federal dietary guidelines were being discussed, there seemed to be a growing consensus that nutritional goals and sustainable goals could be jointly achieved with a single diet.  I pushed back some on that at the time (e.g., see here or here).

I ran across this paper by Zach Conrad and colleagues that was just published in PLoS ONE.  The paper shows that there is unlikely to be a silver bullet diet free of trade-offs when multiple dimensions of comparison are involved.  Here's from the abstract:  

Higher quality diets were associated with greater amounts of food waste and greater amounts of wasted irrigation water and pesticides, but less cropland waste. This is largely due to fruits and vegetables, which are health-promoting and require small amounts of cropland, but require substantial amounts of agricultural inputs. These results suggest that simultaneous efforts to improve diet quality and reduce food waste are necessary.

How to Feed the World

That's the title of a new book edited by Jessica Eise and Ken Foster that was just released last week.  The book is a collection of essays primarily from my colleagues in the Department of Agricultural Economics here at Purdue, but it includes contributions from Purdue faculty in other academic disciplines as well.  I had the privilege of writing the afterward.  

Here is the table of contents:

Chapter 1. Inhabitants of Earth- Brigitte S Walforf
Chapter 2. The Green, Blue, and Gray Water Rainbow- Laura C Bowling and Keith A Cherkauer
Chapter 3. The Land that Shapes and Sustains Us- Otto Doering and Ann Sorensen
Chapter 4. Our Changing Climate- Jeff Dukes and Thomas W Hertel
Chapter 5. The Technology Ticket- Uris Baldos
Chapter 6. Systems- Michael Gunderson, Ariana Torres, Michael Boehlje, and Rhonda Phillips
Chapter 7. Tangled Trade- Thomas W Hertel
Chapter 8. Spoiled, Rotten, and Left Behind- Ken Foster
Chapter 9. Tipping the Scales on Health- Steven Y Wu
Chapter 10. Social License to Operate- Nicole J Olynk Widmar
Chapter 11. The Information Hinge- Jessica Eise
Chapter 12. Achieving Equal Access- Gerald Shively

eisebook.JPG

Gains to Chinese Agricultural Research and Extension

Last week, Nature published this piece on a massive study conducted by Chinese agricultural researchers.  Accompanying the piece was a summary/editorial describing the study:

Running from 2005 to 2015, the project first assessed how factors including irrigation, plant density and sowing depth affected agricultural productivity. It used the information to guide and spread best practice across several regions: for example, recommending that rice in southern China be sown in 20 holes densely packed in a square metre, rather than the much lower densities farmers were accustomed to using.

The results speak for themselves: maize (corn), rice and wheat output grew by some 11% over that decade, whereas the use of damaging and expensive fertilizers decreased by between 15% and 18%, depending on the crop. Farmers spent less money on their land and earned more from it — and they continue to do so.

The project appears to have created substantial economic benefits.  The authors of the study write:

Direct profit, calculated from increased grain output and reduced nitrogen fertilizer use, was US$12.2 billion (Table 1), which does not include relevant environmental benefits associated with reductions in reactive nitrogen losses and in GHG emissions. On the basis of the rough estimates, the cost:benefit ratio would be 1:226.

The cost-benefit ratio is in some ways over- and in other ways under-estimated.  The benefits are over-estimated in the sense that it does not appear it takes into consideration the fact that greater grain production will dampen prices (it is also unclear how the benefits and costs are discounted or not over time).  The benefits are under-estimated because they do not include any of the environmental improvements.  

It is useful to contrast these findings with the rather large research on the value of agricultural R&D and extension investments in the U.S.  Jin and Huffman calculated the rate of return on spending on agricultural extension in the U.S. at 100%.  More broadly, Julian Alston gave the fellow's address at this this year's AAEA meetings on precisely this topic, and his remarks were recently published in the American Journal of Agricultural Economics.  He writes:

Our estimates (Alston et al. 2010a, 2011) indicate that U.S. federal and state government expenditure on agricultural research and extension generates benefit-cost ratios of at least 10:1 (more likely 20:1 or 30:1)—evidence of a serious underinvestment. Pardey and Beddow (2017), echoing Pardey, Alston, and Chan-Kang (2013), suggested that a reasonable first step would be to double U.S. public investment in agricultural R&D—an increase of, say, $4 billion over recent annual expenditures. A conservatively low benefit-cost ratio of 10:1 implies that having failed to spend that additional $4 billion per year on public agricultural R&D imposes a net social cost of $36 billion per year

Given the lower level of development in China, it is certainly possible to imagine that the rate of return on investments in agricultural research and extension being higher than is the case in the U.S.  But, can the benefit cost ration really be 10 times higher in China than the U.S. (226:1 vs. 20:1)?  One interesting thing about Chinese study in Nature is that, if I read correctly, it didn't entail development of any new genetics, pesticides, etc; rather it seemed to largely entail the application of previously developed "science" and practices to the particular geographies in question, and as such, the costs might have been much lower than in situations where new technologies are being created. 

In a sense, the shows an enormously high value to "better information."  This contrasts with perspectives such as this one by David Pannell, who argues that better technologies are much more impactful than "better information."  One way to reconcile this seeming paradox is that that the "information" conveyed to the Chinese farmers was to use better technologies and practices that were already known to exist.  Here in the developed world, the knowledge/technologies are likely already more widely dispersed.  

I'll end with this quote from Alston's paper, who articulated the value of increased productivity in a createive way:

Clearly agricultural productivity growth is enormously valuable. Of the actual farm output in 2007, worth about $330 billion, only one-third (i.e., 100/280 = 0.36) or about $118 billion could be accounted for by conventional inputs using 1949 technology, holding productivity constant. The remaining two-thirds (i.e., 180/280 = 0.64) or about $212 billion in that year alone, is attributable to the factors that gave rise to a 180% increase in productivity since 1949—including improvements in infrastructure and inputs (if not captured already in the indexes), as well as new technology, developed and adopted as a result of agricultural research and extension, and other sources of innovations.

Who Says They Waste Food (and when)?

Applied Economics Perspectives and Policy just published a paper I co-authored with Brenna Ellison entitled "Examining Household Food Waste Decisions: A Vignette Approach."  Here is a summary of the paper:

The purpose of this research is to examine household (consumer) food waste decisions. Because measuring food waste is fraught with difficulty, our first contribution is the application of vignette methodology to the issue of food waste. Our second contribution is to systematically determine how decisions to waste food vary with factors such as price, location, cost of replacement, and freshness, among other factors. The empirical analysis is concentrated on specific food waste decisions: one focused on leftovers from a fully prepared meal and a second related to a single product (milk). The empirical results show that decisions to discard food are a function of consumers’ demographic characteristics and some of the factors experimentally varied in the vignette design.

In particular, each subject saw a description like the following (where they saw one of the values in each of the brackets): 

Imagine this evening you go to the refrigerator to pour a glass of milk. While taking out the carton of milk, which is [one quarter; three quarters] full, you notice that it is one day past the expiration date. You open the carton and the milk smells [fine; slightly sour]. [There is another unopened carton of milk in your refrigerator that has not expired; no statement about replacement]. Assuming the price of a half-gallon carton of milk at stores in your area is [$2.50; $5.00], what would you do? “Pour the expired milk down the drain” or “Go ahead and drink the expired milk”

I suspect you won't be too surprised to hear that "smell" had a significant effect on consumers' decisions to waste or not waste.  Apparently food safety considerations are one key driver of household food waste decisions.  

We also had another vignette surrounding the decision of whether to keep a leftover meal.  The findings?

In the case of meal leftovers, respondents were generally less likely to waste the leftovers when the meal cost was high, when there were leftovers for a whole meal, when there were no future meal plans, and when the meal was prepared at home. Many of these relationships have a very obvious time component. Leftovers can save individuals time when there is enough for a whole meal and there are no future meal plans; further, when a meal is prepared at home, there is already a time cost for that meal (albeit a sunk cost) that people do not want to discount by throwing the leftovers out.

Meat Taxes?

This morning I appeared on Fox Business Network with Varney & Co to discuss the idea of meat taxes (something proposed by many groups and authors - e.g., see this recent piece in Bloomberg).  The short segment is below.  It cut out before my last comment where I argued that efficiency is also good for the consumer because it helps bring down food prices.