Monday, February 5, 2018

Scaling Sustainable Agriculture

As part of getting trained in science communications via the Science Impact Project, I had to prepare and deliver a "TED-style" talk. It was terrifying and hard work, especially to slow down and take a more personal storytelling approach to my work (talking about my family's farm), but I'm pretty happy with the end result.

This blog includes the video of my talk at the top, and the text is more or less a transcript of what I say (with a few additions):

Scaling Sustainable Agriculture (blog at Cool Green Science)

Here is a pic of the farm (we couldn't find many):

and a pic of (from right to left) my great-grandfather Robert and great-grandmother Marjorie (the original farmers), my grandfather Hickman and grandmother Jurie, and two people I'm not sure about!

Thursday, February 1, 2018

February 2018 Science Journal Article Summary

Sad winter kale

The struggle to find good produce in the depth of winter (see my sad kale above) has me thinking about nutrients, so this month I've focused on papers about nutrients in the sense of fertilizer on croplands (focused on N & P, plus one about crop nutrition).

Interested in short blogs or talks? I have a new blog connecting the story of my family's farm with my work on scaling sustainable agriculture. The blog is at and was adopted from my "TED-style" talk: Here's another with the "so what" that was missing from my recent book chapter on global agriculture land use trends.

Finally: unrelated to science, I was impressed how much the Engaging Across Differences has jump-started the way I think about and engage around diversity. They're looking for people to sign up for the next workshops, and I'd encourage all TNC staff to give it serious thought. Let me know if you'd like to discuss further; it's led me to co-host an ongoing workshop at our headquarters about how we can all step up and be better allies to each other.

AGRICULTURE (NITROGEN)The first three papers all come from Xin Zhang at China Agricultural University in Beijing.
Zhang et al 2015 (in Nature) looks at global historic patterns of nitrogen fertilizer use and efficiency, identifying opportunities for improvement. Optimizing nitrogen use efficiency (NUE) means avoiding N loss to the air and water, but also ensuring crops have enough N. Start with Table 1 - which highlights the severe (and worsening) excess in India and China, driven partly by low subsidized fertilizer prices. Fig 4 is also really interesting - it compares efficency in the US and China, partly due to efficiency, and partly due to what we grow (e.g. in the US we grow a lot of soy that doesn't need N).

The other Zhang et al 2015 article (in JEQ) looks at how the economics of promoting technology and best management practices to improve nitrogen use efficiency (NUE) on farms. They model different kinds of improvements, whether they maintain yields at a lower input rate, improve yields at a similar input rate, or improve yields but require more fertilizer as well (e.g. by improving crop genetics). It's a cool (albeit wonky) paper, and Figures 4-7 explore the conditions under which implementing these practices can boost both profit and environmental outcomes. Table 4 shows that for Midwestern corn, at relatively high fertilizer prices improved genetics can be the best strategy, while at lower prices other approaches perform better (with changing the crop running the risk of environmental harm from excess nitrogen). They conclude with policy recommendations around how shifting from subsidies for fertilizer to subsidies for improved practices can help improve NUE. Table 6 has guidelines on how to find the optimal price ranges for both fertilizer and BMPs. A final twist: practices that don't boost yield are less likely to be adopted (even if they save cost), while yield-boosting practices are more appealing but also run more risk of excess N being lost.

Zhang et al. 2017 has some good news in the form of a case study in Huantai county in northern China. While China's overall NUE has gotten worse over the past several decades, it has improved in Huantai. Primary drivers appear to be incorporation of crop straw into soil, and subsidized mechanization of farmland in the area. Overuse of groundwater for irrigation, however, remains a major challenge. Nonetheless, this provides a road map for how the rest of China may be able to follow suit.

Wagner-Riddle et al. 2017 looks specifically at the importance of soil freezing and thawing in correctly estimating N2O emissions. Essentially, when frozen soil thaws, it emits a lot more N2o (a potent greenhouse gas). They estimate that global N2O emissions from cropland may be 17-28% too low due to neglecting to account for soil freezing and thawing.

Sweeney 2017 is another paper finding that long term no-till redistributes soil carbon to the surface but doesn't boost total soil carbon (this case was a claypan soil). More oddly, they found tillage and N fertilization didn't impact soil bulk density or resistance.

AGRICULTURE (phosphorous): The next two articles are cited in this blog about phosphorous (P) in Lake Erie (thanks to Joe F for passing it on, and to Carrie V-S for following up):
Christianson et al. 2016 is a review of phosphorous being lost via farm drainage, both subsurface (tile) drains and surface drains like ditches. There is a lot of interesting data packed in here, but three things jumped out at me. First is that overall P loads were higher in surface drainage than subsurface drainage (Fig 2). The other was that no-till fields lost about triple the P compared to conventional or even conservation tillage. So no-till may reduce sediment losses but increase P losses, presenting an interesting trade-off. Third is that P losses tend to be relatively small (<5% applied) compared to N losses (~15-20%), which reduces the economic incentive for farmers to address P loss.

Jarvie et al. 2017 looked at soluble reactive phosphorous (SRP) in the Western Lake Erie Basin, and looked for correlations with changing agricultural practices. They had data for changes in tillage, and used changing "flashiness" of river flow as a proxy for increased drainage. They note that many factors could have caused the increasing river SRP loads, but attribute 1/3 to increased drainage water flow and 2/3 to an increase in SRP delivery. They concluded that no-till and drainage were both likely responsible for the increasing SRP delivery, but I'm not convinced. Figure 3 and Table 4 show that across the three studied rivers there was not a clear relationship between tillage and drainage and SRP.

I had a few people mention stories about Myers et al 2014 recently about how climate change will impact crop nutrition. This study found that CO2 levels of ~550ppm (which we will likely hit in ~50 years) zinc and iron levels will be lower in wheat, rice, peas, and soy (and wheat and rice having lower protein as well). The decreases are modest; the biggest decline was in wheat, with 9% lower zinc and 5% less iron. This is a legitimate concern (albeit a minor one), but what I find most interesting is how people I spoke to thought the results were much worse. One person told me that even now (not 50 years away) even healthy foods like kale were basically junk food, another thought we were already seeing nutrient deficiencies because of this. So, let's watch out for how climate is changing nutrient density, but in the meantime, keep loading up on those collard greens! If you're worried about zinc and iron there are some great options like pumpkin seeds and sesame seeds. You can read a story about this at and the full article at

Christianson, L. E., Harmel, R. D., Smith, D., Williams, M. R., & King, K. (2016). Assessment and Synthesis of 50 Years of Published Drainage Phosphorus Losses. Journal of Environment Quality, 45(5), 1467.

Jarvie, H. P., Johnson, L. T., Sharpley, A. N., Smith, D. R., Baker, D. B., Bruulsema, T. W., & Confesor, R. (2017). Increased Soluble Phosphorus Loads to Lake Erie: Unintended Consequences of Conservation Practices? Journal of Environment Quality, 46(1), 123.

Myers, S. S., Zanobetti, A., Kloog, I., Huybers, P., Leakey, A. D. B., Bloom, A. J., … Usui, Y. (2014). Increasing CO2 threatens human nutrition. Nature, 510, 139. Retrieved from

Sweeney, D. W. (2017). Does 20 Years of Tillage and N Fertilization Influence Properties of a Claypan Soil in the Eastern Great Plains? Agricultural & Environmental Letters, 2(1), 0.

Wagner-Riddle, C., Congreves, K. A., Abalos, D., Berg, A. A., Brown, S. E., Ambadan, J. T., … Tenuta, M. (2017). Globally important nitrous oxide emissions from croplands induced by freeze–thaw cycles. Nature Geoscience, 10(March).

Zhang, X., Davidson, E. A., Mauzerall, D. L., Searchinger, T. D., Dumas, P., & Shen, Y. (2015). Managing nitrogen for sustainable development. Nature, 528(7580), doi:10.1038/nature15743.

Zhang, X., Mauzerall, D. L., Davidson, E. a, Kanter, D. R., & Cai, R. (2015). The economic and environmental consequences of implementing nitrogen-efficient technologies and management practices in agriculture. Journal of Environmental Quality, 44(2), 312–24.

Zhang, X., Bol, R., Rahn, C., Xiao, G., Meng, F., & Wu, W. (2017). Agricultural sustainable intensification improved nitrogen use efficiency and maintained high crop yield during 1980–2014 in Northern China. Science of The Total Environment, 596–597, 61–68.

Wednesday, January 3, 2018

Take 2: what I wish I'd put in my recent book chapter

I asked my wife Sarah to take a look at my recent chapter in the book "Effective Conservation Science: Data Not Dogma" and she made an excellent point: what should the take-away be? Here are the things I was hoping to convey but wasn't sufficiently clear about.

The key fact I wanted to convey is that the global agriculture situation is complex: the global land used for agriculture hit its peak in 1998 (so it's not true agricultural land is rapidly expanding around the world), BUT in some places there is a lot of agricultural expansion and/or reliance on unsustainable levels of water and nutrients. So there is good news and bad news.

Some other important facts I didn't go into in much detail:
  • In the last two decades we have been able to meet increasing demand for food through intensification (producing more food on existing lands). But going forward projected demand rises faster than what we're likely to be able to produce through intensification. So between 2030-2050 we can expect conversion to agriculture to speed up and lead to a net expansion of land used for agriculture.
  • Agriculture in many regions currently relies on unsustainable irrigation. As groundwater is depleted and crops get thirsty we can expect yields to eventually fall substantially on agricultural lands in water-scarce areas. The California drought gives us a taste of what that could look like. Note that changes in irrigation technology are likely insufficient to solve this on their own (see the summary of Richter 2017).
  • Other agricultural inputs may start to run out or at least limit improved crop yields. That could include rock phosphate for fertilizer or even nitrogen fertilizer if actions to limit climate change make it more expensive.
The key message of the piece for other scientists is: don't assume that things that seem obvious (like ag land rapidly expanding) are true, and don't assume that global data sets are reliable enough to inform policy or other action. Dig deeper! Ask questions, and look for more local data to corroborate your suspicions.

Let me know if you have other questions or suggestions!

Monday, January 1, 2018

January 2018 science journal article summary

Happy new year! Here are a handful of articles focused on global agriculture analyses, plus one with bad news on climate change, and a 2018 #MyScienceResolution. 

Cauliflower, romesco, and broccoli at the farmer's market

 I also want to pass on a cool resource Eddie Game alerted me know. It's a tool to help you figure out which journal to submit a paper to:  You enter the title and abstract of your paper and it gives you a list of appropriate journals. You may also want these tips on how to write an abstract to get found easily in Google and Google Scholar:

On to the articles!

Somehow I'd missed West et al 2014, which is a great (and very short) summary of opportunities to improve agriculture around the world. Just looking at the two figures is highly educational: Fig 1 shows the potential to increase yields on poorly performing croplands to even 50% of their potential yields (which would provide enough food for 850 million more people, while still leaving plenty of room to improve), and Fig 2 shows how much we can reduce environmental impacts of ag in key regions without reducing yields. The spatial patterns aren't surprising, but the specific numbers are highly motivating. For example, China alone produces 28% of global N2O emissions (a potent greenhouse gas). Reducing excessive nutrients and improving water efficiency of crops around the world would have a big impact, as would reducing the amount of animal products we eat and the amount of food that is wasted. Be sure to check out the supplement for more great maps.

Phalan et al 2016 tackles a tricky problem at the heart of TNC's work with ag: how can we ensure that intensification reduces conversion rather than incentivizing it through higher profits? It's under two pages, so I'd recommend just reading it. But the mechanisms they propose to boost yield and promote nature are: 1) land use zoning (specify land for ag and land for conservation, as Costa Rica did), 2) use payments, subsidies, or land taxes (e.g. a program in India where herders set aside habitat in exchange for insurance and technical assistance), 3) "spatially strategic" deployment of tech / infrastructure / ag knowledge (e.g. focusing on staple crops which have more stable demand), and 4) standards (including voluntary ones) and certification. I found this to be good food for thought about how TNC could tighten our theory of change.

Hanspach et al 2017 looks at trade-offs between food security and biodiversity for ag in the "global south" (developing countries). They surveyed 110 self-reported experts and looked for patterns. Surprisingly, while in many landscapes there were clear trade-offs between food security and biodiversity, several respondents reported other cases where the two goals were linked (either in "win-win" or "lose-lose" cases). Figure 2a shows where each landscape fell. Infrastructure, market access, and financial resources were all associated with poor biodiversity but good food security, meaning investment in intensification on its own will likely not lead to conservation outcomes. Social equity and land access were found to be necessary but not sufficient for both food and biodiversity goals. Relying on expert assessments isn't a replacement for good empirical data, but this still has useful elements for TNC to incorporate in our ag work.

Gerber et al 2016 is a global analysis of N2O emissions from croplands. The key point is that areas with very low N use and production can use much more fertilizer with relatively small increases in N2O emissions, while areas with high N excess can use a little less to get big reductions in N2O. For example, cutting N application by 5% in Shandong province (China) would reduce N2O by 9%. Be sure to check out Table 2 (N application totals and rates by country) and Fig 3 (N2O emissions per unit of N applied at a sub-national level), and fig 4 if you're interested in specific crops. Note that they used a new approach which in general predicts significantly lower emissions than other models (they go over several caveats in detail).

Zomer et al 2017 estimates that globally cropland soils could sequester 0.90-1.85 Pg C / yr (1 Pg = 1 billion metric tons) for at least 20 years. This estimate derives from how much soil C has been lost relative to historic levels, along with estimates from an earlier paper of how much sequestration can be achieved through a range of conservation practices (e.g. cover cropping, conservation tillage, rotational grazing, etc.). Table 2 and Figure 2 show where the authors see the most room for improvement (the Midwest US, India, and Europe in particular). TNC's Deborah Bossio is second author so she should be able to answer any questions you may have.

A new paper from NatureNet fellow Kyle Davis (2017) investigates the impact of changing and moving crops on existing croplands around the world to improve yield and reduce water consumption. The hypothetical optimal crop patterns consumed 14% less rainwater and 12% less "blue" water (irrigation from surface and ground), while also producing 10% more calories, 19% more protein, and other benefits. A big caveat is that this involves not only shifting what is grown where (already a big task) but also shifting how much we produce of each crop. For example, they cut production of wheat, rice, corn, and sugar in favor of more soy and tubers (like potato and sweet potato). The interesting part to me is thinking about how this approach could be used in a national land use planning exercise with more realistic constraints.

Brown & Caldeira 2017 has some bad news about climate change. They looked at several climate models and scenarios and evaluated how well they predicted the recent past (looking at 9 variables, not just temperature). They predict warming ~15% higher than currently predicted and have a narrower confident interval for predictions. For climate wonks, they note that emissions in line with the RCP 4.5 scenario are likely to produce warming previously associated with RCP 6.0. There are several important caveats in the discussion, but this nonetheless raises the urgency to take aggressive action on climate to minimize the projected impacts. Take a look at Figuyre 2 which shows the new narrower predictions in red for different emissions scenarios. You can read an overview of the paper here or a longer blog from the authors here:


I haven’t read the Pelger 2017 study it’s based on, but this blog post gave me an idea for a 2018 science resolution! Essentially students writing for a non-scientific audience found that it helped their science writing as well. So if you work as a scientist, commit to writing a blog, or talking to your friends and family about your work without making their eyes glaze over! I'm going to shoot for my next peer-reviewed article to be readable by an ordinary human being. If you need more motivation, check out this inspirational talk by Dan Rather with a vision for a revolution in science communications as a foundation for changing how we think about truth and “fake news” in society: (thanks to Laurel Saito for the link).

Brown, P. T., & Caldeira, K. (2017). Greater future global warming inferred from Earth’s recent energy budget. Nature, 552(7683), 45–50.

Davis, K. F., Rulli, M. C., Seveso, A., & D’Odorico, P. (2017). Increased food production and reduced water use through optimized crop distribution. Nature Geoscience, 10(12), 919–924.

Gerber, J. S., Carlson, K. M., Makowski, D., Mueller, N. D., Garcia de Cortazar-Atauri, I., Havlík, P., … West, P. C. (2016). Spatially explicit estimates of N2O emissions from croplands suggest climate mitigation opportunities from improved fertilizer management. Global Change Biology, 22(10), 3383–3394.

Hanspach, J., Abson, D. J., French Collier, N., Dorresteijn, I., Schultner, J., & Fischer, J. (2017). From trade-offs to synergies in food security and biodiversity conservation. Frontiers in Ecology and the Environment, 15(9), 489–494.

Phalan, B., Green, R. E., Dicks, L. V., Dotta, G., Feniuk, C., Lamb, A., … Balmford, A. (2016). How can higher-yield farming help to spare nature? Science, 351(6272), 450–451.

West, P. C., Gerber, J. S., Engstrom, P. M., Mueller, N. D., Brauman, K. A., Carlson, K. M., … Siebert, S. (2014). Leverage points for improving global food security and the environment. Science, 345(6194), 325–328.

Zomer, R. J., Bossio, D. A., Sommer, R., & Verchot, L. V. (2017). Global Sequestration Potential of Increased Organic Carbon in Cropland Soils. Scientific Reports, 7(1), 15554.

Friday, December 1, 2017

December science journal article summary

2008-01-26 (Editing a paper) - 31
Photo from Nic McPhee under Creative Commons license


As we approach end of year deadlines, I've been doing less science reading. I'm guessing others are in the same boat, so this is a small review. The focus this month is how we can do science in a way that leads to greater impact. Two articles are about writing science articles more clearly, two are about collaboration, and one is a call for academics to do more to promote action in sustainability. Enjoy!

Many scientists bristle at the notion that we should write more clearly. But we also hate reading articles and finding they don't deliver on what the title and abstract promises. Mensh & Kording 2017 offers 10 rules for writing more clearly. Different disciplines have different norms around structure, language, etc., but I think this is a great place to begin. Short on time? Read Table 1 (on p8) which summarizes the rules and how to know if you get it wrong. I'm excited to try this for my next paper!

Ever wonder how scientists pick authorship order, sort out who did what, and decide who's on a paper at all? If so, you may want to skim Sauermann & Haeussler 2017. It's on the long and dense side, but has some interesting insights (especially if you're a scientist making those decisions). In general, contribution statements offer more info than author order (although they can be hard to read), see Figure 4. Figure 1 shows that after the first author, the last author is most likely to have played a broad role in the paper. Finally, I was struck by the "inclusion as an author" section on page 4 which lists an international standard for being an author which is significant higher than what I usually see. Basically, this is food for thought for folks who read and/or write a lot of science papers.

As we increasingly focus on big, tough problems, collaboration across sectors is more important than ever. It's also really hard. In cross-sector projects I've worked on, differences in terminology, priorities, expertise, etc. have slowed down progress. The Bridge Collaborative is an initiative led by TNC aiming to help collaboration across environmental, development, and health sectors. Their new guidance report has insights for those of you doing this kind of cross-sector work (or aspiring to).

Bodin 2017 asks a more basic question: when and how does collaboration really make sense (with a specific focus on collaborative governance for environmental problems)? Their brief answer: "The capacity of collaborative governance to deliver sustainable solutions for any given environmental problem ranges from highly effective to essentially worthless." That may seem flippant, but he provides useful parameters to answer the question for a given context. The 1-page summary is better written than the longer version (which is broad enough to feel a bit unfocused), but the long version has details about knowledge diffusion and building functional social networks that people trying to work in this way will likely appreciate.

Keeler et al 2017 is a paper led by some folks at the Natural Capital Project (with current and former TNC co-authors) calling for academic institutions and do more to help "serve society and the planet." It's a quick and well written read, but they have five main ideas: provide training to help students become environmental leaders (not just professors), recognize the value of applied / relevant work (which is sometimes seen as inferior to basic research), move faster (accepting uncertainty and the need for iteration), make people front and center in environmental science, and shift academic structure to encourage innovation (e.g. NatCap itself is one example of academics partnering with NGOs to do rapid applied science). I often meet academics frustrated that their work isn't being put to ues more, and this gives them some ideas of changes to promote at their institutions.

Bodin, Ö. (2017). Collaborative environmental governance: Achieving collective action in social-ecological systems. Science, 357(6352), eaan1114.

Keeler, B. L., Chaplin-Kramer, R., Guerry, A. D., Addison, P. F. E., Bettigole, C., Burke, I. C., … Vira, B. (2017). Society Is Ready for a New Kind of Science—Is Academia? BioScience, 67(7).

Mensh, B., & Kording, K. P. (2017). Ten simple rules for structuring papers. PLOS Computational Biology, 13(9).

Sauermann, H., & Haeussler, C. (2017). Authorship and contribution disclosures. Science Advances, 3(11), e1700404.

Tallis H, Kreis K, Olander L, Ringler C et al. 2017. Bridge Collaborative Practitioner’s Guide: Principles and Guidance for Cross-sector Action Planning and Evidence Evaluation. Washington DC: The Nature Conservancy

Wednesday, November 1, 2017

November science journal article summary

Nihao November!

Fall sumac

I've got a good one for you this month! It's less focused than usual, but there are three key topics, plus a mix of a few others:
First, if you're about to delete this unread, please take this survey (which takes <1 minute) to let me know if you have input on how these summaries could be more useful: . Thanks to all who responded; results are summarized at the end of this email.

Second, the long-awaited "Natural Climate Solutions" paper from TNC is out. Read it: it's only 5 pages and will be highly relevant to virtually everyone working in conservation. It makes a solid case for how immediately investing in nature to reduce GHGs can buy us much-needed time to bring down emissions and invent new technology.

Third, a new book came out Oct 12: Effective Conservation Science: Data Not Dogma. It includes chapters from myself and several TNC authors, and is full of fascinating stories of how we react to science that counters conventional wisdom. I also share related articles below on how we can work through our biases.

Griscom et al 2017 (the natural climate solutions paper) packs a lot of good content in, but two things in particular excite me. First is making the case for massive rapid investment in nature: while we develop new tech and bring down emissions, we can use proven solutions like trees to buy time and make progress (see figure 2: nature could get us 37% of mitigation needs by 2030 at <$100/t CO2e / yr). We need the tech too, but nature is something that works today to bring down GHGs. Second is breaking down their top 20 options for nature-based climate mitigation into the theoretical maximum impact (about 1/2 of which would cost <$100 / t CO2e / yr), what we would need to hit Paris targets of <2 degrees C, and the subset of mitigation which is cheap (<$10/t CO2e / yr). See Figure 1 for this breakdown, which highlights that forests are absolutely critical (2/3 of cost-effective mitigation), and that the biggest opportunities for cheap mitigation are preventing forest loss (and improving forest management), improving fertilizer use on farms, and keeping peatlands intact. The forest goals rely heavily on a small reduction in grazing lands (4%). I'm leaving out lots of important details to keep this short: just read the paper. It's worth it. Read all about it (or watch videos) at

The book Effective Conservation Science: Data Not Dogma tells stories of scientists whose unconventional and inconvenient results challenge us all to broaden our thinking and consider how we respond to new information that undermines what we think we know. My chapter is around how my analysis and blog post showing that globally agriculture has been taking up a smaller footprint since 1998. You can buy the book here: and read a review of one chapter here: and read an ugly (unformatted) version of my chapter here:  

Here are three more papers on the topic of scientific bias:
In 1992 E.O. Wilson asserted that invasive species were the second greatest driver of species extinction (second only to habitat destruction). He did so without providing evidence or details behind his calculations, but this claim was rapidly repeated and taken as gospel by environmental scientists. In fact, TNC played a major role in elevating Wilson's claim by not only citing it (in a BioScience paper and related book), but adding that "scientists generally agree" with Wilson's claim (again without evidence). Chew 2015 tells the captivating story about how this happened, using clear writing, thought-provoking questions, and numerous examples of bias in language that should be neutral and scientific. He also tells us how the idea eventually became subject to critique. I have seen this phenomenon firsthand; I follow a trail of citation breadcrumbs from authors to discover a primary source with an assertion that cannot be supported by what's in the paper (e.g. a book chapter on soil by Rattan Lal). When scientists don't closely read the papers we cite (or read them at all), our biases blossom and spread. If you're interested in invasive species or how spurious claims spread, this is a great read (albeit long).

Warren et al 2017 asks how common it is for scientists to be biased with regard to invasive species: using value-laden language and favoring interpretation that emphasizes the impacts of invasive species even when the data are not clear (as exemplified by the Chew 2015 article). They found bias to be common, but also that it has been declining since a series of papers in 2004-2005 that argued against language vilifying invasive species. This paper is fairly simplistic but gets at a key nuance: even a bias which is generally true is counter-productive in science. This paper shows hope that with awareness of bias, we can make efforts to at least reduce the expression of that bias in our work.

Holman et al 2015 provides more evidence of scientific bias, and argues for the use of "blinding" when conducting research to limit the potential for bias to affect study results. This means scientists collecting data don't know whether the subjects or area they're observing is a treatment or a control. This makes it harder for preconceptions to affect measurements (whether subjective, or even "rounding" seemingly objective metrics to fit bias), and they present evidence that nonblind studies often inflate the effect of the actions being studied. If "working blind" sounds extreme to you, read my blog post about "Clever Hans" - a horse who was believed to be able to do math (but in fact was only skilled at reading when his audience believed he had the right answer):

As a final thought on bias, check out the Minasny & McBratney article in the Soil section below, which challenges a key assertion for TNC's agriculture work (that boosting soil organic matter improves water holding capacity). Read the summary below, and observe your feelings and reaction if it challenges what you believe.

Minasny & McBratney 2017 use a meta-analysis to argue against something generally believed to be true by people working on sustainable agriculture: they provide evidence that increasing soil organic matter has a relatively small effect on water holding capacity (particularly for plant-available water content). If they're right, it reduces TNC's argument that improving soil health via boosting organic matter on farms will substantially improve crop resilience to drought. The authors note that soils that benefit most from increases in organic matter are sandy and very low in organic matter to begin (both of which make sense). They have a good discussion of limitations of their analysis, in particular the fact that they focused only on soil and not what's above it. Cover crops and crop residue / stubble are likely to add to the small benefits shown via soil. There is also a lot of nuance and potential to reframe their analysis in a way that could show larger benefits. At the same time, recognizing that most of us have a bias on this topic, this is a useful reminder to check our assumptions about both the efficacy of practices and the key mode of action and metrics that we should focus on. The authors led a key paper on the "4 per mille" initiative on boosting soil carbon, so are not hostile to the notion of boosting soil carbon. You can read a news article about this one here:

Remember as a kid how many bugs would get splattered on the windshield of your car? Ever notice there are less now? A recent study (Hallman et al 2017) indicates this is a real phenomenon, with dramatic declines in flying insects. The authors tracked the total biomass of insects at 63 locations within nature preserves in Germany; from 1989 to 2016 biomass plummeted by 76%. They sampled several habitat types and found consistent declines. It's alarming to see this within protected areas, although the authors note virtually all are surrounded by agriculture. That could both pull insects away from natural areas, and provide more pesticide drift into the natural areas. Other studies have shown major insect declines, but none this severe, and I don't know of others within protected areas.

I've been pondering what we think we know and how to communicate thorny issues (as per data not dogma). I'd recommend a book I'm reading: "Do I make myself clear?" by Harold Evans, which is helping me. While not for scientists, I saw my writing sins laid bare in this book. I'm looking to simplify my writing in science papers, and to better talk about science in general. I have a long way to go! I'm working on summarizing key lessons amidst all of the stories in the book. One useful tool is the Hemingway app, which helps you identify problematic text and how to improve it:

As noted in my August 2017 review, neonicotinoids (neonics for short) are a class of insecticide currently under close scrutiny for impacts on bees. Mitchell et al 2017 found neonics in 75% of the 198 honey samples they tested, although mostly at very low levels. All neonics were at safe levels for humans, and most were at levels considered safe for bees. This is useful to show both that these pesticides are very common, that they are being consumed by bees, and that they often occur in concert with other neonics (all of which is concerning). But the reporting (and fundraising) around this has glossed over the very low levels. While 48% of samples had total neonic levels over a very conservative threshold for potential harm to bees (0.1 ng / g, a more reasonable (still likely conservative, albeit arbitrary) threshold of 2 ng / g was only detected in 8% of samples. The honey was collected via "citizen science"; the researchers asked colleagues, friends, and family to bring them honey produced in a known location. That also raises the question of whether or not these honey samples are typical.

I'm guessing the folks who didn't respond would have had more critical feedback, but overall here's what I learned from the ~40 respondents:
  • 90% of you usually at least skim these for relevant content
  • 90% of you found the level of detail about right (including some who said they could use less detail but were content to tolerate the current length), the rest found them too long.
  • Several folks especially liked both grouping articles by topic, and focusing each month primarily on one topic. I'll endeavor to keep that up, despite failing to do so this month.
Some opportunities to improve I'll be mulling over:
  • Set up a monthly journal club to talk about the papers (this one is already in the works, stay tuned for more info and let me know if you would like to provide input)
  • Make a lead theme more clear up front and include a short summary of the entire email
  • Tie each article to TNC's shared conservation agenda
  • Each quarter send a list of bullets of main issues under debate in conservation to encourage us to follow up
Chew, M. K. (2015). Ecologists, Environmentalists, Experts, and the Invasion of the “Second Greatest Threat.” International Review of Environmental History, 1, 7–41. Retrieved from 

Evans, H. (2017). Do I make myself clear? Why writing well matters. Little, Brown, and Company: New York, NY. 416p.

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Wednesday, October 18, 2017

New book: "Effective Conservation Science: Data not Dogma"

I have a chapter in a new book that was just published:
Effective Conservation Science: Data not Dogma (click the link to read more and buy it if you like).

The book has a really cool theme: what happens when we find evidence that contradicts what "everyone knows"? How do people react, and how do we resolve the disconnect?

In my case, while doing research for another book, I discovered that global land used for agriculture had actually been declining since 1998, despite the narrative that ag was rapidly expanding around the world.

I got a lot of pushback when I blogged about it a few years ago, and this chapter tells the story of what I found, what the reaction was, and what it all means going forward.

I really think the book is a great read based on the several chapters I've read so far, so if you're interested I encourage you to buy it. If you're not sure, you can read a review of a different chapter, or read the ugly (unformatted) version of my chapter here:
Global agricultural expansion: the sky isn't falling (yet)

Here's a map showing where around the world agriculture IS expanding, and where it's contracting: