December 2019 science journal article summary

Greetings,

This month I've just got a couple articles each on soil and learning from failure, plus one on social and environmental synergies and trade-offs. If you know someone who wants to sign up to receive these summaries, they can do so at http://bit.ly/sciencejon

Also, as a reminder, I'm hosting a webinar on December 3 (1p EST) with recommendations on how scientists may be able to achieve more real world impact via their research. You can learn more and register here: https://zoom.us/webinar/register/WN_Q78ubqH9TL6tkmLQCRyAsw and read the draft paper the talk is based on at http://bit.ly/strongerscience

SOIL:
Our paper opining on soil carbon (Bradford et al. 2019) is out! The opening two lines sum it up well: "Soil-based initiatives to mitigate climate change and restore soil fertility both rely on rebuilding soil organic carbon. Controversy about the role soils might play in climate change mitigation is, consequently, undermining actions to restore soils for improved agricultural and environmental outcomes." In other words, while scientists disagree a lot about whether boosting soil carbon is useful for climate mitigation, we all pretty much agree it's important for fertile and productive agricultural lands. Read a bit more at http://sciencejon.blogspot.com/2019/11/soil-carbon-what-is-it-good-for.html or just read the paper (it's only 1,800 words).

Lugato et al. 2018 uses daycent to model the net GHG impact of building soil carbon in farms via cover crops, reduced tillage, and keeping crop residues. They found a lot of variation across sites, but that overall reducing tillage and crop residue retention offered modest but long term (>80 years) net GHG benefits without impacting crop yield much. N-fixing cover crops led to stronger C sequestration and net GHG reductions over the first 20 years, but after 40 years it switched to being a GHG source (due to N2O) that strengthened over time (albeit with a small crop yield boost). If fertilization wasn't reduced to account for the new N from the cover crop, it would be a stronger GHG source much sooner. They also didn't model non-N-fixing cover crops like rye.


ORGANIZATIONAL LEARNING / FAILURE:
Catalano et al. 2018 argues that conservation would do well to learn how to deal with failure from other disciplines like medicine, business, and aviation. Specifically, we need to recognize how much we can learn from failure (sometimes more than success), rather than fearing it and avoiding tough measures as a result. They cover how we learn from failure, why it's hard to constructively engage with it, how understanding cognitive biases can help (see Table 1 for a great list to consider), and the role of leaders in supporting efforts to identify and learn from failure. The example of "no rank" military aviation debriefs is interesting - they promote a culture with sharing useful feedack at its core. My main take-away is that dealing with failure is not only key, but it's hard and requires careful thought to do well.

Catalano et al. 2019 is an analysis of 59 peer-reviewed articles discussing reported conservation failure (Table 2 has a great list of synonyms and euphemisms for failure). Most articles did use the term failure, and almost half did so in the abstract. See Table 3 for an interesting typology of causes of failure (including people, action, information, funding, and economic and political) and how common each was, and Table 4 for example text of each kind. Overall they found reporting failure in conservation is rare (~1/4 as often as reporting success), it's typically not framed as useful for learning, and 'people' are the most common cause of failure (e.g. especially stakeholder relationships, but also bad past experiences, fear, etc.). They also call for authors to report failure in a way that makes it easy for others to learn from their mistakes.


PEOPLE AND NATURE:
Gill et al. 2019 looks at 75 studies across 4 kinds of marine conservation work to evaluate social and environmental synergies and tradeoffs (as well as equity). Specifically: marine protected areas (MPAs - representing the majority of studies considered), community-based MPAs, environmental certification, and community-based management (CBM). They found diverse impacts, but with very few rigorous studies designed to show causality. But there was potential for both positive and negative cascading effects depending on access to resources (especially for fishers). Fig 6 has an interesting breakdown of how many studies covered each subtopic, and provides some potential categories of trade-offs to think about.


REFERENCES:
Bradford MA, Carey CJ, Atwood L, Bossio D, Fenichel EP, Gennet S, Fargione J, Fisher JRB, Fuller E, Kane DA, Lehmann J, Oldfield EE, Ordway EM, Rudek J, Sanderman J, Wood SA. 2019. Soil carbon science for policy and practice. Nature Sustainability .

Catalano AS, Redford K, Margoluis R, Knight AT. 2018. Black swans, cognition, and the power of learning from failure. Conservation Biology 32: 584–596.

Catalano AS, Lyons-White J, Mills MM, Knight AT. 2019. Learning from published project failures in conservation. Biological Conservation 238: 108223.

Gill DA, Cheng SH, Glew L, Aigner E, Bennett NJ, Mascia MB. 2019. Social Synergies, Tradeoffs, and Equity in Marine Conservation Impacts. Annual Review of Environment and Resources 44: 347–372.

Lugato E, Leip A, Jones A. 2018. Mitigation potential of soil carbon management overestimated by neglecting N2O emissions. Nature Climate Change 8: 219–223.


Sincerely,

Jon

p.s. If you'd like to keep track of what I write as well as what I read, I always link to both my informal blog posts and my formal publications (plus these summaries) at http://sciencejon.blogspot.com/

August 2019 science journal article summary

Photo from Mick Garratt

Greetings,

Hot weather and a vacation in the woods have me thinking about climate change and habitat conversion (with articles on deforestation, landscape conservation, biodiversity, and livestock sustainability).

If you know someone who wants to sign up to receive these summaries, they can do so at http://bit.ly/sciencejon

LANDSCAPE CONSERVATION:
Runting et al. 2019 argues that debates about 'land sparing' vs 'land sharing' miss an important point - good forest management is likely more important. They run several scenarios with different degrees of land sharing vs sparing, and conventional vs. improved management (reduced-impact logging, longer plantation rotation, and strictly enforcing protected areas). They saw the best outcomes with improved management and a mix of sparing and sharing (but favoring sparing, see Figure 4). Check out Figure 2 for what an 'optimal' scenario looks like compared to extreme sharing or sparing (but ignore the idea that tiny islands of protected areas or holes in larger ones are ideal - this is almost certainly an artifact). There's a blog on this one at https://nature4climate.org/news/headline-stories/cant-see-the-wood-for-the-trees-making-the-most-of-our-forests-for-biodiversity-and-wood-production/

Kennedy et al. 2019 calculates how modified by human activities land around the world is. While only 5% of land area was 'unmodified', most of the world was 'moderately modified.' The authors argue that ecoregions with moderate modification may be good candidates for high priority conservation action, because they tend to have some relatively intact lands near to highly modified lands (which thus may pose a threat in the near future). In particular, the tropical and subtropical dry broadleaf forests biome (mostly in Mexico, India, Argentina, & SE Asia) was found to be the most threatened (high conversion relative to protection). While they didn't include all threats (e.g. logging, invasive species, climate change, and more) these data can be used to evaluate the suitability of lands for protection. You can explore the findings and maps at http://gdra-tnc.org/current/ and you can download the data from http://s3.amazonaws.com/DevByDesign-Web/Apps/gHM/index.html


CLIMATE CHANGE:
Bastin et al. 2019 estimate 900 million ha of land could be reforested globally (excluding cropland and urban areas), which could store 205 Gt of carbon (752 Gt CO2e). Alternatively, they predict we'll lose 223 million ha of forest by 2050 under business as usual. This paper has been broadly criticized for overstating the role of reforestation in climate mitigation (while reforestation is important, the authors' conclusion that it's the most important solution is a fringe opinion), especially since they call for a focus on boreal plantings which reduces albedo relative to bare snow and ice (thus reducing the climate mitigation contribution). Here's a blog covering the paper including the critique: http://blogs.discovermagazine.com/crux/2019/07/10/reforestation-climate-change-plant-trees/#.XSdzAehJE2w

Diaz et al. 2018 looks at trade-offs between different forest management options for Douglas-fir in the NW US that could improve carbon storage. They compare managing the land to optimize net present value (NPV) to managing for sustained timber yield (with different levels of environmental management, e.g. longer rotations and some aspects of FSC certification). They find that environmental constraints boost carbon storage but hurt net present value. For example, one scenario had 26% more carbon, but 15% less timber and 21% lower NPV. They explore different policy options and challenges related to driving more carbon storage in timberlands.


DEFORESTATION:
Lambin et al. 2018 look at how effective company commitments to end deforestation are. The key finding is that public policy can significantly improve the likelihood of reducing deforestation relative to private action alone. For example, the Soy Moratorium combined sector-wide commitments with monitoring and public disincentives to clear forest in Brazil, with some success. They call for better company commitments (as called for by the Accountability Framework, https://accountability-framework.org/), and recommend public policies including: legal reform & enforcement, land tenure reform, working with people clearing the most forest, broadening scope (companies, commodities, & regions), incentivizing all actors in the supply chain to participate (e.g. fertilizer companies rarely engage in these commitments), improving traceability and transparency, and increasing demand for deforestation-free products.


LIVESTOCK SUSTAINABILITY:
Schader et al. 2015 looks at how shifting what we feed cattle could improve sustainability. The idea is to feed them less food humans could eat (like corn), and more grass and by-products we can't or don't eat (e.g. distiller's grains, bran, oilseed cake, etc.), which also limits the total amount of livestock which can be raised in this way. Figure 1 is a great overview of what this would mean, for example a big reduction in pigs and chicken and only modest increases in other livestock (that can eat grass). But note a cardinal data visualization sin: inconsistent scaling of bar charts (e.g. the soil erosion from water chart makes it look like their preferred scenario has only 42% the erosion of the reference scenario, but it actually has 88% the erosion) which means you have to look carefully. Still, it's an important concept to explore, and a useful contribution to the conversation.

What are the barriers to using livestock practices that reduce GHGs? Kipling et al. 2019 asked Welsh ranchers and other stakeholders in a series of interviews and workshops. They focused on the conceptual framework rather than the practices, splitting them into practical limitations (e.g. costs and infrastructure, see Figure 1), knowledge limitations (being unaware of options and how they work, see Figure 2), and cognitive limitations and interests (complexity and competing values, see Figures 3 & 4). There aren't any big surprises here, but it's a useful overview, especially the quotes from ranchers for each concept they present.


BIODIVERSITY:
Humphreys et al. 2019 looks at recent (since 1900) and historic plant extinction, and compares it to animal extinctions. The most interesting findings are that the IUCN Red List data on extinct plants are pretty poor (with 50 Red List species incorrectly listed as extinct, and 491 extinct species missing from the Red List), that 54% of plants reported extinct were later rediscovered (or reclassified to be the same as an extant species), that thousands of extant plant species are 'functionally extinct' (too few exist to form a viable population going forward), and that 55% of the 571 plant species that have gone extinct have done so since 1900. This is a short paper and worth reading.

REFERENCES:
Bastin, J.-F., Finegold, Y., Garcia, C., Mollicone, D., Rezende, M., Routh, D., … Crowther, T. W. (2019). The global tree restoration potential. Science, 365(6448), 76–79. https://doi.org/10.1126/science.aax0848

Diaz, D. D., Loreno, S., Ettl, G. J., & Davies, B. (2018). Tradeoffs in timber, carbon, and cash flow under alternative management systems for Douglas-Fir in the Pacific Northwest. Forests, 9(8), 1–25. https://doi.org/10.3390/f9080447

Humphreys, A. M., Govaerts, R., Ficinski, S. Z., Nic Lughadha, E., & Vorontsova, M. S. (2019). Global dataset shows geography and life form predict modern plant extinction and rediscovery. Nature Ecology & Evolution, 3(July). https://doi.org/10.1038/s41559-019-0906-2

Kennedy, C. M., Oakleaf, J. R., Theobald, D. M., Baruch-Mordo, S., & Kiesecker, J. (2019). Managing the Middle: A Shift in Conservation Priorities based on the Global Human Modification Gradient. Global Change Biology, (June 2018), 1–17. https://doi.org/10.1111/gcb.14549

Kipling, R. P., Taft, H. E., Chadwick, D. R., Styles, D., & Moorby, J. (2019). Challenges to implementing greenhouse gas mitigation measures in livestock agriculture: A conceptual framework for policymakers. Environmental Science and Policy, 92(November 2018), 107–115. https://doi.org/10.1016/j.envsci.2018.11.013

Lambin, F., Gibbs, H. K., Heilmayr, R., Carlson, K. M., Fleck, L., Garret, R., … Walker, N. (2017). The role of supply-chain initiatives in reducing deforestation. Nature Climate Change, 8(February), 109–116. https://doi.org/10.1038/s41558-017-0061-1

Runting, R. K., Ruslandi, Griscom, B. W., Struebig, M. J., Satar, M., Meijaard, E., … Venter, O. (2019). Larger gains from improved management over sparing–sharing for tropical forests. Nature Sustainability, 2(1), 53–61. https://doi.org/10.1038/s41893-018-0203-0

Schader, C., Muller, A., El-Hage Scialabba, N., Hecht, J., Isensee, A., Erb, K. H., … Niggli, U. (2015). Impacts of feeding less food-competing feedstuffs to livestock on global food system sustainability. Journal of the Royal Society Interface, 12(113). https://doi.org/10.1098/rsif.2015.0891



Sincerely,

Jon

p.s. If you'd like to keep track of what I write as well as what I read, I always link to both my informal blog posts and my formal publications (plus these summaries) at http://sciencejon.blogspot.com/

Tips on lowering your carbon footprint

I was recently interviewed by budgetdumpster.com for some tips about how to lower your carbon footprint. There are a couple of things in the article that aren't quite right, but overall it's a good collection of things you can do to reduce your impact on climate change. The article is called:
11 Quick and Relatively Painless Ways to Lower Your Carbon Footprint

Hint: one of them is not to simply switch to smaller and more adorable planes:

reThink Soil: A Roadmap to U.S. Soil Health

We just released a new report on the potential benefits of adoption soil health practices in the U.S., and the conclusions are pretty exciting! You can read a brief overview, the executive summary, and the full paper at http://nature.org/soil. Much of the analysis was done by consultants we worked with, but I provided lots of scientific guidance and review throughout the process.

The web page has a good summary of some of the key points, but to put it even more succinctly, we argue that the adoption of three soil health practices (no-till, cover crops, and crop rotations) on U.S. row crops could have massive benefits both to society (e.g. improved water quality, reduced GHGs) and to the farmers implementing them (reduced soil erosion, improved soil quality and resilience).

For instance, if half of the farmland used to grow corn, soy, and wheat were to adopt all three practices, it could generate $7.4 billion in total benefits, and if all the farmland for those three crops adopted them it could be $19.6 billion (note that it's not double because some farms already use some of these practices). If you take the more optimistic upper range of our estimates, total societal benefit for 100% adoption of all three practices could be $49.8 billion. A lot of the science is uncertain, so these estimates are rough but we drew on the best available data to come up with them, and we are confident that the magnitude of the opportunity is valid even if the exact numbers are off.

U.S. Beef Supply Chain - Impacts and Opportunities

Surprisingly, there are very few assessments of the overall environmental impact of beef across the supply chain (looking at all phases of their life). The only ones we've found have a clear bias either favoring industrial systems or grass-finished systems. So, The Nature Conservancy decided to fill that gap with a rapid assessment.

Longhorn in Southwest Missouri from Flickr user Jeff Weese. https://www.flickr.com/photos/jeffweese/3896957110/. Used under Creative Commons license (https://creativecommons.org/licenses/by/2.0/)

We looked at major impacts and opportunities to improve for each of the different production phases: ranch and farm grazing (cow-calf ranches, stockers, backgrounders, etc., when they're roaming about and grazing), feed production (growing hay / silage and row crops to be fed to cattle), feedlots (operation of the feedlot where they're fattened not including growing the feed), and harvest facilities (slaughterhouses).

You can read a bit about the report and our major findings here:

https://www.nature.org/en-us/what-we-do/our-insights/perspectives/sustainability-and-the-u-s--beef-supply-chain/

The report can be directly downloaded here:

https://www.nature.org/content/dam/tnc/nature/en/documents/us-beef-supply-chain-report.pdf

The most interesting / surprising finding to me was that the grazing phase actually had the biggest impact. The key is that while it's fairly low impact per acre, it's by far both the largest footprint and where cattle spend the most time. So put together we actually see more greenhouse gas emissions, water quality impacts, and wildlife habitat impacts from that grazing phase.

A couple of key notes: Walmart provided funding for this report but had no editorial control or input into the content of the paper. Also, this was a rapid assessment (it took place over 6 months in between other work) by a small team of four scientists, so we do not have all the answers. Some critical issues we didn't have time to assess include impacts of dairy cattle, a comparison of the impact of beef to other protein sources (vegetable and animal), animal welfare and social issues, and the return on investment of different sustainability options (e.g. what would provide the most benefit per dollar spent). That's all important but was too much for us to tackle.

Finally, I occasionally have people ask me "Why should I trust you (as a vegan, or as an environmentalist) to give me accurate information about livestock and agriculture?" My answer is usually the same, which is that I encourage people not to simply trust me: instead look at the work, check my assumptions / calculations / sources, and come to your own decision about whether or not the analysis has merit. My job is to be as honest, accurate, and transparent as possible to make that process easy. Along those lines, I'm happy to take questions / critiques here.

Carbon Footprint of Tomatoes

I worked with some colleagues from the Nature Works Everywhere program on this video about the carbon footprint of tomatoes. You can read more about it and grab a lesson plan if you like.


The Industrial Tomato from The Nature Conservancy on Vimeo.