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The Dust Bowl

I just finished the Worst Hard Time by Timothy Egan, published back in 2006, about the Dust Bowl.  

On several levels, I had a deep connection to the themes in the book.  I can recall stories from both my mother's and father's mothers (my grandmothers) about growing up in the dust bowl era in and around the regions Egan discusses in his book.  As a child I can remember going with my dad to a nearby shelter-belt (which I presume was part of Roosevelt's plan to avert the dust bowl, at least according to Egan) to chop wood for our fireplace.  

Egan repetitively makes the argument (with a tedium that bored me at times) that the the great plains should have never been plowed.  It should, in his assessment, have been left in natural grasses.  The dust bowl itself, in Egan's account, was a result of man's hubris that nature could be tamed.  

Egan's account paints both a cynical and overly-optimistic view of government.   On the one hand, the government partially caused the great plow up (citing mainly from government reports at the time):

"Mistaken public policies have been largely responsible for the situation," the report proclaimed.  Specifically, "a mistaken homesteading policy, the stimulation of war time demands which led to over cropping and over grazing, and encouragement of a system of agriculture which could not be both permanent and prosperous."  

...

"The settlers lacked both the knowledge and the incentive necessary to avoid these mistakes.  They were misled by those who should have been their natural guides.  The Federal homestead policy, which kept land allotments low and the requirement that a portion of each should be plowed, it now seems to have caused immeasurable harm.  The Homestead Act of 1862, limiting individual holding to 160 acres, was on the western plains almost an obligatory act of poverty."

On the other hand, Egan suggests the government-man Hugh Bennett's plans of contour plowing and grass-reseeding along with Roosevelt's plan of shelter-belts and farm price support policies saved the day.  

I'm not so sure.  It is tough to separate compelling journalistic story from data-driven explanations.  My own  sense coming into the book is that much of the land I grew up around, which falls within the area Egan draws around the dust bowl era, is as plowed up as it ever has been.  The data would seem to support that too.  I dug up USDA data on the number of acres planted to wheat in Cimarron Co, OK (which is where Boise City is located - one of the spots featured in Egan's book).

wheatacres.JPG

While there was indeed a big plow-up just prior to the dust bowl (which occurred in the 1930s), we can see that we've had just as much land in wheat production in the late 1940s and almost as much in the late 1970s.  To the extent that the same is true in other regions and with other crops, it doesn't seem that replanting back to grass is THE explanation (although it might have played some role on more erodible lands in other areas).

A better question.

In the past several years, we've had severe droughts in the great plains similar to the one in the 1930's.  Why no repeat of the dust bowl?  

Egan asks a similar question, and he points mainly to the aforementioned government policies. He also gives the impression in the end that big corporate agribusinesses have taken over this land (which is largely false; there are fewer farmers today and those farmers are indeed bigger, but they are family farms; moreover his statements on this topic are somewhat ironic given the aforementioned quote that larger farm sizes were needed to avoid poverty).  As indicated in the graph above, I don't think the full answer can be that the land has reverted back to idyllic native grasses.  

My sense is that it is mainly a result of two factors: better farming technologies/practices and irrigation.  To be fair, Egan points to these as potential answers too.  Many of the people who moved out to farm the great plains had no prior farming experience.  Its no wonder they adopted some practices that were doomed for failure (I'm sure I'd have done the same thing; I'd hate to think what would happen if I were forced to try to make a living at farming today!)  Knowledge and experience matter.  And sometimes it takes really bad consequences to teach us to do things differently.

On the issue of irrigation, there was an interesting paper (earlier ungated version here) that recently appeared in the American Economic Journal: Applied Economics by Richard Hornbeck and Pinar Keskin.  They write:   

Agriculture on the American Plains has been constrained historically by water scarcity. Post-WWII technologies enabled farmers over the Ogallala aquifer to extract groundwater for large-scale irrigation. Comparing counties over the Ogallala with nearby similar counties, groundwater access increased agricultural land values and initially reduced the impact of droughts. Over time, land use adjusted toward water intensive crops and drought sensitivity increased. Viewed differently, farmers in nearby water-scarce areas maintained lower value drought-resistant practices that fully mitigate naturally higher drought sensitivity. The evolving impact of the Ogallala illustrates the importance of water for agricultural production, but also the large scope for agricultural adaptation to groundwater and drought.

Ultimately, we may never know the ultimate causes and consequences of the dust bowl.  It seemed to arise from a unique combination of an adverse turn in weather/climate, poor farming practices, poor economic conditions (the Dust bowl and the Great Depression occurred at the same time - how's that for bad luck!), unscrupulous land salesmen, and bad government policies.  The consequences, it seems, were long lasting.

Hornbeck has another 2012 paper (earlier ungated version) specifically on the dust bowl in the American Economic Review related to how long the impacts of the dust bowl were felt.  He wrote:

The 1930s American Dust Bowl imposed substantial agricultural costs in more eroded Plains counties, relative to less-eroded Plains counties. From 1930 to 1940,
more-eroded counties experienced large and permanent relative declines in agricultural land values: the per acre value of farmland declined by 30 percent in high erosion counties and declined by 17 percent in medium-erosion counties, relative to changes in low-erosion counties. 

and

The Dust Bowl provides a detailed context in which to examine economic adjustment to a permanent change in environmental conditions. The Great Depression may have slowed adjustment by limiting access to capital or outside employment opportunities. Agricultural adjustment continued to be slow, however, through the 1940s and 1950s. Further research on historical shocks may help understand what conditions facilitate long-run economic adjustment. The experience of the American Dust Bowl highlights that agricultural costs from environmental destruction need not be mitigated mostly by agricultural adjustments, and that economic adjustment may require a substantial relative decline in population.

Information manipulation a good idea? I think not

Fuhai Hong and Xiaojian Zhao have an article forthcoming in the American Journal of Agricultural Economics entitled Information Manipulation and Climate Agreements.  They write:

It appears that news media and some pro-environmental organizations have the tendency to accentuate or even exaggerate the damage caused by climate change. This article provides a rationale for this tendency by using a modified International Environmental Agreement (IEA) model with asymmetric information. We find that the information manipulation has an instrumental value, as it ex post induces more countries to participate in an IEA, which will eventually enhance global welfare. From the ex ante perspective, however, the impact that manipulating information has on the level of participation in an IEA and on welfare is ambiguous.

The authors seem to to want to rationalize information manipulation, even making it a part of the acceptable "tool box" of policy levers.  They conclude:

In addition to other approaches for dealing with the free-riding problem, including taxation, quota systems, privatization, etc., this article introduces a novel mechanism, “information manipulation.”

The authors construct a mathematical model to suggest that exaggerating consequences can have positive impacts by getting people to "do the right thing".  But, this can only be true in the narrowest of senses.  How does one know that exaggeration will cause the "right" amount of public response, rather than causing a diversion of resources away from other productive uses?  More importantly, what happens when people find out they were misled?  How will the public respond to the next information/manipulation campaign? Degrading the public trust is surely not a long run beneficial strategy.  

And, what can we say about a group of citizen that now have biased beliefs relative to the true state of the world?  Jo Swinnen and colleagues have written on this issue arguing that activist organizations often try to slant information to acquire more donations, and in the process can lead people to have biased beliefs (even if people started out believing the truth).  In one paper in the European Review of Agricultural Economics, they write:

we review the analysis and communication of organisations active in the food policy arena and review a series of hypotheses to explain their apparent change of views as reflected in their public statements. In particular, we analyse how communications to potential donors in fund-raising affects the overall communication strategy of the organisation. We explain how policy organisations’ (POs) competition for donors’ funding may lead to ‘bias’ in their policy communications. Bias in policy communication may draw in larger revenues through fund-raising, but it may have negative welfare effects if it induces suboptimal behaviour by various other agents who use this advice for their decision-making.

For scientists to have any long-run credibility, we need to tell the truth as best we know it: uncertainties and all.

Does Whole Foods Sell Pseudoscience?

A colleague sent me a link to this interesting article in the The Daily Beast by Michael Schulson who argues that Whole Foods is the Temple of Pseudoscience.  He notes:

My own local Whole Foods is just a block away from the campus of Duke University. Like almost everything else near downtown Durham, N.C., it’s visited by a predominantly liberal clientele that skews academic, with more science PhDs per capita than a Mensa convention.

Still, there’s a lot in your average Whole Foods that’s resolutely pseudoscientific. The homeopathy section has plenty of Latin words and mathematical terms, but many of its remedies are so diluted that, statistically speaking, they may not contain a single molecule of the substance they purport to deliver. The book section—yep, Whole Foods sells books—boasts many M.D.’s among its authors, along with titles like The Coconut Oil Miracle and Herbal Medicine, Healing, and Cancer, which was written by a theologian and based on what the author calls the Eclectic Triphasic Medical System.

You can buy chocolate with “a meld of rich goji berries and ashwagandha root to strengthen your immune system,” and bottles of ChlorOxygen chlorophyll concentrate, which “builds better blood.” There’s cereal with the kind of ingredients that are “made in a kitchen—not in a lab,” and tea designed to heal the human heart.

Schulson goes on to ask:

So, why do many of us perceive Whole Foods and the Creation Museum so differently?

His answers related to differences in perceived harm to society and whether the perpetrator is a business or not.  I didn't find the answers all that compelling but not sure I have anything better to offer.  In fact, I think some of it is almost exactly the opposite of what Schulson posits.  Whole foods sells products that don't seem like they're sold from a business - at least the big bad businesses.  They sell the idea that their company (and those stocking products on their shelf) put your health above corporate interests.  A quick look at the receipt after checkout might disabuse one of that notion.  I also think people tend to think about food differently than other issues and there is a hypersensitivity (at least in our relatively rich developed world) to perceived risk that is often conveyed as a sort of morality.  

 As Jonathan Haidt put it in the The Righteous Mind:

And, why do so many Westerners, even secular ones, continue to see choices about food and sex as being heavily loaded with moral significance? Liberals sometimes say that religious conservatives are sexual prudes for whom anything other than missionary-position intercourse within marriage is a sin.  But conservatives can just as well make fun of liberal struggles to choose a balanced breakfast - balanced among moral concerns about free-range eggs, fair-trade coffee, naturalness, and a variety of toxins, some of which (such as genetically modified corn and soybeans) pose a greater threat spiritually than biologically.

Is portion size to blame for obesity?

I've often seen presentations where the authors show the size of an average hamburger or soda in the 1960s, 70s, 80s, and 90s as a way of making the point that portion sizes have increased, and thus contributes to the rise in obesity.  Changes in portion size probably have played some role, but at least according to this experiment published in the journal Obesity, it may play less of a role than first meets the eye. The researchers recruited over 233 people working in a large medical complex and randomly assigned them to treatments that differed according to the size of the free lunch they were given (one control group was given no free lunch at all).  Here's what they found:

Adults (n = 233) were randomly assigned to one of three lunch size groups (400 kcal, 800 kcal, and 1,600 kcal) or to a no-free lunch control group for 6 months. . . .

Body weight change at 6 months did not significantly differ at the 5% level by experimental group (1,600 kcal group: +1.1 kg (SD = 0.44); 800 kcal group: −0.1 kg (SD = 0.42); 400 kcal group: −0.1 kg (SD = 0.43); control group: 1.1 (SD = 0.42); P = 0.07). Weight gain over time was significant in the 1,600 kcal box lunch group (P < 0.05).

A remarkable increase in portion size from 400 kcal to 1600 kcal for lunch over a 6 month time period resulted in no statistically significant differences in weight across groups at the end of the period.  If you compare the pre- and post-weight of the people in the 1600 kcal group, there was a slight increase (0.19kcal/month) in weight for people in that group but not for people in the 400 kcal group or the 800 kcal group.  Curiously, those in the control treatment, which included people who were not given a free lunch, gained a statistically significant 0.24 kcal/month - more than those in the 1600kcal free lunch group! 

The trouble with many "interventions" such as this (similar to those that happen at school lunches) is that people can substitute across time.  If I eat a big lunch, I'm likely to eat less for dinner. And vice versa.  If I eat a 400 kcal lunch, I'm more likely to grab a snack in the afternoon than if I eat a 1,600 kcal lunch.  

Apply this thinking to related policy ideas.  Ban sodas or transfats. What will people drink and eat instead?  Tax restaurants.  What will people eat at home?  Add more veggies to the plate at school.  What will happen to veggie consumption at home?  I'm not saying that such policies might not have some effect on weight, only that because of substitutes and compensating behavior, they will often have less effect than is expected.