Is the growth in agricultural productivity slowing?

Last week I gave a talk at the University of Nebraska, and Julian Alston from UC Davis was also there.  He presented some recent research with Matt Anderson and Phil Pardey about productivity growth in agriculture.  While I have seen some discussions about the possibility of a slowdown in productivity growth in developing countries, Alston's research suggest it is a phenomenon alive and well here at home.  This is important stuff.  Falling productivity growth has important implications for sustainability, food security, and research and development. They write: 

“We detect sizable and significant slowdowns in the rate of productivity growth. Across the 48 contiguous states for which we have very detailed data for 1949– 2007, U.S. multifactor productivity (MFP) growth averaged just 1.18 percent per year during 1990–2007 compared with 2.02 percent per year for the period 1949–1990. MFP in 44 of the 48 states has been growing at a statistically slower rate since 1990. Using a longer-run national series, since 1990 productivity growth has slowed compared with its longer-run growth rate, which averaged 1.52 percent per year for the entire period, 1910–2007. More subtly, the historically rapid rates of MFP growth during the 1960s, 1970s and 1980s can be seen as an aberration relative to the long-run trend. A cubic time-trend model fits the data very well, with an inflection around 1962. We speculate that a wave of technological progress through the middle of the twentieth century—reflecting the progressive adoption of various mechanical innovations, improved crop varieties, synthetic fertilizers and other chemicals, each in a decades long process—contributed to a sustained surge of faster-than-normal productivity growth throughout the third quarter of the century. A particular feature of this process was to move people off farms, a one-time transformation of agriculture that was largely completed by 1980.”

Here's a graph from their paper showing the change in proportional growth rate in yields (i.e., the log of yields) over time for 6 crops with the inflection point indicated for when growth rates began decelerating.  

Agri-Pulse Interview on GMOs

I was recently interviewed by Agri-Pulse about GMOs, GMO labeling, and technology adoption.  You can hear the whole thing here.

End of Doom

Ronald Bailey has an excellent piece in the October print edition of Reason Magazine entitled, "The End of Doom" and a recently released book with the same title.  It's a nice counterweight to the oft-heard refrain that the world is going to hell.  

Here are a a few quotes I found particularly interesting.  In critiquing Rachel Carson's Silent Spring:

“At its heart is this belief: Nature is beneficent, stable, and even a source of moral good; humanity is arrogant, heedless, and often the source of moral evil. Carson, more than any other person, is responsible for the politicization of science that afflicts our contemporary public policy debates.”

In discussing our out-sized fears of cancers from synthetic chemicals and of biotechnology:

“It should always be borne in mind that environmentalist organizations raise money to support themselves by scaring people. More generally, Bonny observes, “For some people, especially many activists, biotechnology also symbolizes the negative aspects of globalization and economic liberalism.” She adds, “Since the collapse of the communist ideal has made direct opposition to capitalism more difficult today, it seems to have found new forms of expression including, in particular, criticism of globalization, certain aspects of consumption, technical developments, etc.””

He ends with some choice words about the precautionary principle.  

“Why does it matter if the population at large believes these dire predictions about humanity’s future? The primary danger is they may fuel a kind of pathological conservatism that could actually become a self-fulfilling prophecy.”

and

“The precautionary principle is the opposite of the scientific process of trial and error that is the modern engine of knowledge and prosperity. The precautionary principle impossibly demands trials without errors, successes without failures.

...

”An indirect implication of trial without error is that if trying new things is made more costly, there will be fewer departures from past practice; this very lack of change may itself be dangerous in forgoing chances to reduce existing hazards.” ”

GMO animals

In the past couple weeks, I've seen several articles on GMO animals.  They are often created using cisgenic techniques or gene editing (i.e., moving genes within a species or "turning off" expression of existing genes), so they may (or may not) be more acceptable to consumers than transgenic GMOs.  That said, the research suggests consumers are much more averse to genetic engineering in animals as compared to plants (for example, here's one recent study we conducted).  

Here's a sampling of the stories and applications mentioned:

Tamar Haspel in National Geographic - mentions bird-flu resistant chicken (well, they're not actually resistant but they don't spread the disease).

David Cyranoski in Nature News - mentions "double muscled" pigs.

Hannah Devlin in the Guardian - mentions pigs resistant to African swine fever (includes a nice graphic).

Kat McGowan in Mother Jones - mentioned polled (or hornless) Holstein cows (bet you didn't know almost all dairy cows currently have to be dehorned), also mentions more heat tolerant cows.

This is an old one but don't forget the larger, faster growing transgenic salmon.

It will be interesting to see how this field develops and how consumers respond.  Reducing proensity for disease and need for dehorning are clear animal welfare improvements, and of course more efficient animals mean less environmental impacts and lower prices.  Will that assuage consumer concerns?  Only time will tell.

Addendum:  Ellen Goddard reminded me of this story on transgenic cows that have higher Omega 3s

Wheat Yields and Temperature Change

I'm quite sure I've never seen an article in the Proceedings of the National Academies of Science written by a former teacher, a former student, and  a friend at a former employer.  Well, that changed yesterday.   Three top notch agricultural economists, Jesse Tack, Andy Barkley, and Lanier Nalley, just released a paper published in PNAS about the effect of hot and cold temperatures on wheat yields.   

The abstract:

“Climate change is expected to increase future temperatures, potentially resulting in reduced crop production in many key production regions. Research quantifying the complex relationship between weather variables and wheat yields is rapidly growing, and recent advances have used a variety of model specifications that differ in how temperature data are included in the statistical yield equation. A unique data set that combines Kansas wheat variety field trial outcomes for 1985–2013 with location-specific weather data is used to analyze the effect of weather on wheat yield using regression analysis. Our results indicate that the effect of temperature exposure varies across the September−May growing season. The largest drivers of yield loss are freezing temperatures in the Fall and extreme heat events in the Spring. We also find that the overall effect of warming on yields is negative, even after accounting for the benefits of reduced exposure to freezing temperatures. Our analysis indicates that there exists a tradeoff between average (mean) yield and ability to resist extreme heat across varieties. More-recently released varieties are less able to resist heat than older lines. Our results also indicate that warming effects would be partially offset by increased rainfall in the Spring. Finally, we find that the method used to construct measures of temperature exposure matters for both the predictive performance of the regression model and the forecasted warming impacts on yields”

There's more discussion about the study in this piece in the Washington Post.