Redefining Agricultural Yields

I saw some recent discussion on Twittter of this post by Emily Cassidy in which she discusses her 2013 paper in Environmental Research Letters coauthored with Paul West, James Gerber, and Jonathan Foley.  The subtitle of her post and paper is: "from tonnes to people nourished per hectare."

It's an interesting and thought provoking piece, and at the heart of it are figures like this one Cassidy posted on her blog:

She writes:

And as you can see from the map above, a lot of farmland in the United States is not used to grow food, it is used to grow animal feed and biofuels. Over two-thirds of the calories grown in the U.S. are fed to livestock. And for every eight calories of corn and soybean fed to livestock, only one of those calories ends up on our plates.

In the published paper, the authors argue they, "illustrate where tremendous inefficiencies in the global food system exist today" and reach the normative judgement that, "shifting the use of crops as animal feed and biofuels would have tremendous benefits to global food security and the environment."  

There are some methodological issues that I think are important in this discussion, some of which the authors themselves acknowledge and discuss, but I'll get to those in a minute.  

First, I want to make the case that this state of affairs is not as "inefficient" or "irrational" as is often portrayed.  

For one, take a look at the above figure.  Is there some commonality between the locations with more green (more production for "food" - supposedly the "good" outcome)?  These locations tend to be the spots that are relatively poorer, hungrier, and more malnourished.  That ought to give us pause - that the locations with the supposedly "good" farming practices have some of the biggest challenges with under-nourishment.  

Now, we shouldn't mistake correlation with causation (i.e., production for "food" probably isn't causing food security problems), rather I suspect this pattern is largely explained by income effects.  What we're probably seeing in the above graphs relates not to production practices per se but to preferences of relatively rich people vs. relatively poor people.  Our production practices are constrained by what people want to buy.  In the same way one can argue it's "inefficient" for a relatively wealthy person to have a bigger car or bigger house or private jet, one can also point out that this sort of person has the means to pay for enjoyable things that are somewhat less efficient.  If all we cared about was caloric/protein efficiency, we humans should eaten a spartan, undiversified diet of beans and rice. So, that's the first answer: people in relatively richer countries eat more meat because they like it and they can afford it.  Maybe we shouldn't like or want to eat animal products, but as economists are fond of saying, de gustibus non est disputandum.

Beyond "preferences", why do we grow so much corn, soy, and wheat in the U.S.?  A primary answer is that these plants are incredibly efficient at converting solar energy and soil nutrients into calories (they're the best, really the best).  Moreover, these calories are packaged in a form (seeds) that are highly storeable and easily transportable - allowing the calories to be relatively easily transported to different times and to different geographic locations.  Contrast these crops with directly-human-edible fruits/vegetables like kale, broccoli, or tomatoes.  These plants are poor converters of solar energy to plant-stored energy (i.e., they're not very calorie dense), and they are not easily storeable or transportable without processing (mainly canning or freezing), which requires energy.

This gets to some of the methodological issues in these sorts of calculations.  As I've discussed before using various analogies, there are two ways to view livestock.  One is that they are inefficient - using up a lot of energy to make food.  Another is that they are good at converting one form of energy that is highly storeable/transportable but untasty (field corn, soy, sorghum) to another form (eggs, meat, dairy) that we like to eat.  Rarely do these sorts of research papers include the the calories (or energy) used in food processing.  It is a mistake to compare the calories in steak to the calories in a wheat kernel.  The wheat kernel requires energy/processing to convert to flour and then more energy to get pasta or bread.  In the developing world (largely the green countries in the above graph), I suspect a lot of this processing isn't measured because it occurs in the household.  The cowpeas, cassava, or beans require grinding and cooking to be human-edible, and the energy used to accomplish this isn't measured.  The historian Rachel Laudan has written eloquently on this in a number of places (see her blog or book), and it is a feature of our modern food system that is vastly under-appreciated.

The other two issues the authors mention in their journal article as worthy of additional research are food waste and the ability of livestock like cattle to convert human-inedible calories from grasses into human-edible meat/dairy.  On that last topic, there is a nice report by the Council for Science and Technology written Jude Capper and others.  To those issues, I'd also add that we need to think about water use (the corn/soy/wheat in the U.S. is largely un-irrigated whereas fruits/veggies require comparatively large amounts of water often supplied by irrigation; of course, livestock consume water too) along with use of other inputs like pesticides and fertilizer (again, fruits/veggies can be relatively heavy users of pesticides).

Where does that leave us?  I'm not going to say it's perfectly rational for the U.S. to devote the majority of it's cropland to corn/soy/wheat, but I think this discussion suggests it's not irrational either.  

P.S.  In terms of tonnes of production USDA data suggest in the 2016-2017 marketing year, 40% of the corn/sorghum/barley/oats produced and imported in the U.S. went to "food, alcohol, and industrial use", 32% went to "feed and residual use",  14% was in "ending stocks" (i.e., it was stored for future use), 14% was exported, and the small remaining amount was "seed use".                     

Personal Choices to Reduce Greenhouse Gas Emissions

This article in Environmental Research Letters by Seth Wynes and Kimberly Nicholas calculates the ways various personal choices affect greenhouse gasses. The paper has received a lot of attention in the media (e.g., see here or here).   At the heart of the issue are the results from this figure in the original paper showing the relative effect of different actions on greenhouse gas emissions.


The findings led to headlines like this one in The Guardian, "Want to fight climate change? Have fewer children."  The findings are interesting on a number of fronts.  For example, I regularly see stories suggesting that the most impactful thing one can do to fight climate change is eat less meat.  That strategy shows up as a mere 7th on this chart, and way, way behind having children (not having a child has more than 60 times the emissions impact as moving to a more plant based diet).  

The implication that we should have fewer children raises a number of thorny issues that have long been debated.  Since at least Malthus, folks have been worried about a growing world population.  Stanford biologist Paul Ehrlich has raised alarm since the 1960s about the dire consequences of a "population bomb."  At the heart of this thinking is the premise that an extra person is a kind of threat: a threat to food security, a threat to the climate, a threat to the environment.  There's even a bit of a hint of this thinking in the common mantra of many agricultural organizations that we need to do what we can so that we can feed nine billion people by 2050.  The extra people that will arrive in the next 30 years or so are placing a burden on us today to increasing productivity.  

An alternative perspective, one often attributed to Julian Simon, is that an extra person is a blessing rather than a curse.  People aren't just consumers of resources but are are sources of ideas, creativity, and ultimately new resources.  An extra person isn't a threat but an opportunity.

Regardless of where one falls in this debate, it should be noted the above graph looks at just one side of the equation: the cost of an extra human in terms of extra greenhouse gasses.  What is ignored is the potential benefit of an extra human.  What is the opportunity cost of a foregone Einstein, Edison, or Jobs?  Going further, who are the folks most likely to heed the advice to forego children for the climate, and what would their would-be kids have been like?

It is also worthwhile mentioning that there is no guarantee that population will continue to grow, particularly if the world continues to develop and incomes rise.  Even the UN projections place some probability on a population decline in 30 years time.  One writer of Wired magazine, Kevin Kelly, when asked what we should be worried about (but presumable are not), fretted about about an underpopulation bomb.  Here's what he writes:

Here is the challenge: This is a world where every year there is a smaller audience than the year before, a smaller market for your goods or services, fewer workers to choose from, and a ballooning elder population that must be cared for. We’ve never seen this in modern times; our progress has always paralleled rising populations, bigger audiences, larger markets and bigger pools of workers. It’s hard to see how a declining yet aging population functions as an engine for increasing the standard of living every year. To do so would require a completely different economic system, one that we are not prepared for at all right now. The challenges of a peak human population are real, but we know what we have to do; the challenges of a dwindling human population tending toward zero in a developed world are scarier because we’ve never been there before. It’s something to worry about.

 A couple final thoughts.  The above graphs shows several possible mitigation options, but I haven't heard much discussion of tradeoffs.  Surely the end goal in life isn't to focus all our individual energies on activities to reduce carbon emissions.  So, given my preferences for driving, eating meat, or being a parent, the figures above suggest useful ways of thinking about this problem.  Maybe I don't want to have a more plant-based diet, but at least in terms of greenhouse gas impacts, I can "offset" that and more by foregoing my trip to Paris this year.  

More broadly, we don't normally worry about impacts of our various consumption choices on availability of other resources like steel or fertilizer or labor.  Why?  Because the market price for the goods should reflect the relative scarcity of these items.  One upside to a carbon tax is that we could forego all the moralizing and all these sorts of "consumption advice" types of papers and simply allow consumers to make choices they want given the relative prices of different goods.  But what about children?  The above graph would seem to justify a large carbon tax on having kids.  I'd guess that is a highly unpopular idea, which suggests to me that most of us are more likely to be in the Simon camp than the Ehrlich one when thinking about our own offspring.  


A couple weeks ago, the lawsuit between BPI, the maker of lean finely textured beef (LFTB), aka "pink slime", and ABC news finally came to an end after the two parties agreed to an settlement for an undisclosed amount of money (here's one summary from CNN).

Here's another story from Inside Sources that touches on the economic impacts of the original ABC news coverage.  They reached out to me for comment and you can read a tad bit of what I had to say at the link above.  

Better yet, check out the chapter in my book 2016 Unnaturally Delicious entitled "Waste Not Want Not."  In that chapter, I talked about the history of BPI and it's founder Eldon Roth, the technology used in creating LFTB, some intriguing background on how BPI wound up in the documentary Food, Inc., and more.  Here are the law few paragraphs from that chapter.    

It’s a bit hard to know what to make of all that transpired. To be sure, much of what was said about BPI was sensationalized. BPI didn’t use organ meats or bones or hoofs or hides or
“dog food.” The company used slightly fattier versions of same beef cuts that usually become roasts or ground beef. In fact, the day I visited BPI’s South Dakota plant, which is adjacent to a
Tyson packing facility, I was amazed at the beef entering BPI’s facility. The meat traveled on a conveyer belt in a tunnel that connects BPI and Tyson. A steer or heifer enters one end of the
Tyson facility, and a few hours later beef trimmings emerge at BPI without ever seeing the light of day. The trimmings consist of some small cuts of beef but there are also huge hunks of meat that looked almost identical to the briskets that I love to barbeque for get-togethers with friends and family. Lean finely textured beef is beef. That’s all. I suppose that’s why the company created a website called No bone goes into the process. Big beef hunks go in one end and out the other end come three products: tallow, cartilage (which is the only waste), and lean finely textured beef.

I’ve visited a lot of food plants, and BPI’s was one of the most technologically advanced, safety-conscious plants I’ve seen. That a company that proactively invested millions in food safety measures found itself embroiled in controversy involving perceived (but unfounded) safety concerns is deeply ironic. What tarnished BPI’s reputation was no actual sickness or recall or outbreak; it was a series of TV shows and news stories.

But, given the information that consumers received, it is hard to fault them for their reaction. After all, best-selling authors and journalists have primed the public’s distrust of Big Food. In
an era when processed food has come to be seen as almost evil, “pink slime” struck a chord with consumers. Perhaps BPI should have required labeling of the beef that contained its products. Surely some of the public outcry arose from a feeling of having been deceived and of having no control over what is in our food. But from BPI’s perspective, what’s to label? “This product of ground-up beef parts contains more ground-up beef parts”? More fundamentally, BPI didn’t sell directly to consumers. Rather, the company sold to other processors, who sold to restaurants and grocery store chains. BPI was hardly in a position to force others to label products that contained lean finely textured beef.

So where does that leave us? Many shoppers, although I am not among them, no doubt want to avoid lean finely textured beef and are willing to pay a premium to purchase lean ground beef that does not contain it. There’s no harm in that.

But if we are really concerned about food waste, we probably need to change some of our narratives. We shouldn’t say we want companies to recycle and reuse and then turn around and vilify them for doing so.

The comedian Jon Stewart, who was more than willing to jump on the Big-Food-is-bad bandwagon, remarked that pink slime should instead be called “ammonia-soaked centrifuge-separated by-product paste.” He was working off a popular narrative. He could have instead featured the harm to a family owned business that was innovating to make food safer and more affordable by preventing food waste. But that’s not very funny.


Today is my official first day as Professor and Head of the Agricultural Economics Department at Purdue University.  The department was recently ranked 4th in the world and I'm excited to see what we can do to make headway on the three slots in front of us!  While I will no doubt continue to post some cowboy-related items, don't be surprised if you start seeing some boilermaker content.   

Freedom of Information Request

About a year ago, I had a freedom of information request (FOIA) from Gary Ruskin with U.S. Right to Know (USRTK) asking for all my correspondence with a long list or organizations and people from Monsanto to the Bill & Melinda Gates Foundation.  The request wasn't surprising given that I've written a lot about biotechnology, and it had been widely publicized that Ruskin's organization had issued FOIA requests to a large number of academics who'd written positive things about GMOs.

At the time, I chose not to post anything about the FOIA request largely because it wasn't much of a nuisance to me (but it was a cost to the Oklahoma tax payers who funded the lawyers and IT folks who pulled together the documents), and I didn't feel I had anything to hide.  Moreover, I generally support the ability of a free press to use FOIA, recognizing that it can become (and probably has become) abusive in some instances.  

However, last week, I ran across this post by the Berkeley economist David Zilberman who received a FOIA request from a journalist regarding his communications surrounding GMOs.  David's reaction to his request was similar to mine.   In particular, I wondered why Mr. Ruskin didn't just pick up the phone and call me?  I would have been happy to talk.  I was struck by the impersonal, legalistic approach.  Maybe Mr. Ruskin would have still wanted to issue a FOIA request after a chat, but at least we would have had a chance to share our perspectives, motivations, etc.    

Here is David's reaction:

Compliance with the FOIA of Mr. Carollo will take time and effort. It takes him a few minutes to write the request and it will take me much time and digging to respond. The right to request a FOIA is a privilege, and as a professional he needs to use carefully. In my view, he needed to put some time to learn about the subject of his inquiry before he presents his legal but costly demand.

Googling my name he could have easily discovered Were you paid by Monsanto? • The Berkeley Blog, where I state that I received $10,000 for reviewing some papers for Monsanto (out of millions of dollars of support grants for my research over the years from many sources). He would have known that I have made many contributions to support environmental causes. He could even have called or emailed me — my phone number (510-290-9515) and email ( are available on my website – and he would have better knowledge about his “suspect.” If after this initial and more personal investigation he would have asked me to provide him with information, I would have been happy to oblige according to the FOIA.

The last part is the best:

I am left with a feeling of disappointment in our culture of confrontation and lack of collegiality. I hope that journalists and in fact, all citizens, will realize that we in academia are dedicated to the truth as much as they are — and while there may be rotten apples in each profession, they should know us better before they burden us. In a way FOIA is like GMOs, a very valuable tool, which has to be applied with care.