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), and read another blog I wrote on the chapter with better framing and explanation here: Take 2: what I wish I'd put in my recent book chapter
Here's a map showing where around the world agriculture IS expanding, and where it's contracting:
This blog mostly summarizes useful science I read, and promotes my own research. Content posted here is my own and does not reflect the opinions of my employer or anyone else. I tweet at @sciencejon and my bio is at http://fish.freeshell.org/bio.html
Wednesday, October 18, 2017
Sunday, October 1, 2017
October science journal article summary
Here's some science
to make your October outstanding! I have a 3-question survey about these
summaries that should take a minute or less to answer; please consider taking
it (or emailing me if you prefer). I'm trying to get a sense of how often
people read them, whether the level of detail is right or not, and get any
other feedback people have: https://www.surveymonkey.com/r/BCVDKQR
The focus of this
review is on reducing the impacts of animal agriculture (especially cattle).
For anyone who missed my June 2016 review, I'll re-recommend Herrero et al 2016
as a fantastic overview of the potential for improving GHG emissions in the
livestock sector. Their top picks were improved feed digestibility (including
more cereals, distiller's grains, etc. to supplement or replace grass and hay),
feed additives, avoiding land use change through intensification, and carbon
sequestration from better grazing.
ANIMAL AGRICULTURE:
There a lot of
discussion on how to shrink the high carbon footprint of cattle (beef and
dairy), and one focal area is on enteric methane (mainly cow burps). Hristov et
al 2015 is a study showing that a feed additive (3NOP) was able to reduce dairy
methane production by ~30% (with oddly similar impact regardless of the dose)
without substantially affecting milk yield (although it increased weight gain
by 80% over the 12 week period). This is a relatively small study (48 cows) and
it would be see what the impact is throughout the life of dairy cattle (as
often gut flora adapts to these kinds of additives over time), but this
combined with a couple of similar studies they cite are exciting enough to be
worth recommending more trails and pilots.
Kinley et al 2016 is
a similar paper looking at a different feed additive (this one based on
seaweed). This is only an in vitro study (messing with petri dishes rather than
actual cows) but they found adding doses of 2% or greater to a grass diet
virtually eliminated methane production. Note that a very similar paper
(Machado et al 2015) had similar results, but with two key differences: they
saw a strong benefit at 1% dose (where Kinley had a weaker response at that
dose), and they also saw some side effects that could impact cattle health at
2% and above. While this was only in vitro and only tested for 3 days, it's
still worth investigating and comparing to 3NOP for efficacy and potential
positive and negative side effects.
Swain et al 2018 (it
came out online early) is a paper from the Breakthrough Institute arguing for a
shift to more intensive livestock systems, especially switching from
grass-finished to grain-finished beef. They make a number of good points; it's
not really debatable that feedlot cattle require less land and time, and most
scientists agree the GHG emissions are lower per unit of meat in feedlot
systems as well. They briefly discuss some of the potential tradeoffs including
animal welfare and antibiotic use and how they might be addressed, and the
issue of how to ensure that higher productivity actually leads to land sparing
as opposed to driving more habitat conversion. While a good read, there are a
few things they don't cover that should also be part of the conversation. One
is that in some cases we may actually prefer a high land use footprint, if the
grazing lands are high-quality natural grasslands that would otherwise be
converted to other uses. But it's still a worthwhile read with good food for
thought.
Odadi et al. 2017
(authored by a NatureNet fellow, along with TNC's Joe Fargione) looks at the
impact of planned grazing (focus on intensive rotational grazing, but including
several other factors) on a variety of outcomes in Kenya. They found substantial
improvements in vegetation (cover, species richness and diversity, etc.),
presence and richness of wildlife, cattle weight gain during dry periods when
they were in poor condition, and the amount of cattle supported per unit of
land area. The cool thing to highlight here is that they were able to improve
cattle condition as well as wildlife habitat. One critical ingredient to
success was more active involvement from pastoralists; this does mean more
effort for them but it appears that the benefits make it worth promoting.
AGRICULTURE:
Remember the
synthesis of evidence for how several agricultural practices impact a suite of
outcomes that Rodd Kelsey led (I sent it out last month)? This month I'm
sharing one more 2-page document, which has a great chart summarizing the
evidence for each of the practices evaluated on each of the outcomes. If you
want to explore more deeply, you can do so at http://www.conservationevidence.com/data/index/?synopsis_id[]=22
REFERENCES:
Herrero, M., Conant, R., Havlik, P., Hristov, A. N., Smith, P., Gerber, P., … Thornton, P. K. (2016). Greenhouse gas mitigation potentials in the livestock sector. Nature Climate Change, 6(May), 452–461. https://doi.org/10.1038/nclimate2925
Hristov, A. N., Oh, J., Giallongo, F., Frederick, T. W., Harper, M. T., Weeks, H. L., … Duval, S. (2015). An inhibitor persistently decreased enteric methane emission from dairy cows with no negative effect on milk production. Proceedings of the National Academy of Sciences of the United States of America, 112(34), 10663–10668. https://doi.org/10.1073/pnas.1504124112
Kinley, R. D., De Nys, R., Vucko, M. J., MacHado, L., & Tomkins, N. W. (2016). The red macroalgae Asparagopsis taxiformis is a potent natural antimethanogenic that reduces methane production during in vitro fermentation with rumen fluid. Animal Production Science, 56(3), 282–289. https://doi.org/10.1071/AN15576
Machado, L., Magnusson, M., Paul, N. A., Kinley, R., de Nys, R., & Tomkins, N. (2016). Dose-response effects of Asparagopsis taxiformis and Oedogonium sp. on in vitro fermentation and methane production. Journal of Applied Phycology, 28(2), 1443–1452. https://doi.org/10.1007/s10811-015-0639-9
Odadi, W. O., Fargione, J., & Rubenstein, D. I. (2017). Vegetation, Wildlife, and Livestock Responses to Planned Grazing Management in an African Pastoral Landscape. Land Degradation and Development, (March). https://doi.org/10.1002/ldr.2725
Swain, M., Blomqvist, L., McNamara, J., & Ripple, W. J. (2018). Reducing the environmental impact of global diets. Science of the Total Environment, 610–611, 1207–1209. https://doi.org/10.1016/j.scitotenv.2017.08.125
Hristov, A. N., Oh, J., Giallongo, F., Frederick, T. W., Harper, M. T., Weeks, H. L., … Duval, S. (2015). An inhibitor persistently decreased enteric methane emission from dairy cows with no negative effect on milk production. Proceedings of the National Academy of Sciences of the United States of America, 112(34), 10663–10668. https://doi.org/10.1073/pnas.1504124112
Kinley, R. D., De Nys, R., Vucko, M. J., MacHado, L., & Tomkins, N. W. (2016). The red macroalgae Asparagopsis taxiformis is a potent natural antimethanogenic that reduces methane production during in vitro fermentation with rumen fluid. Animal Production Science, 56(3), 282–289. https://doi.org/10.1071/AN15576
Machado, L., Magnusson, M., Paul, N. A., Kinley, R., de Nys, R., & Tomkins, N. (2016). Dose-response effects of Asparagopsis taxiformis and Oedogonium sp. on in vitro fermentation and methane production. Journal of Applied Phycology, 28(2), 1443–1452. https://doi.org/10.1007/s10811-015-0639-9
Odadi, W. O., Fargione, J., & Rubenstein, D. I. (2017). Vegetation, Wildlife, and Livestock Responses to Planned Grazing Management in an African Pastoral Landscape. Land Degradation and Development, (March). https://doi.org/10.1002/ldr.2725
Swain, M., Blomqvist, L., McNamara, J., & Ripple, W. J. (2018). Reducing the environmental impact of global diets. Science of the Total Environment, 610–611, 1207–1209. https://doi.org/10.1016/j.scitotenv.2017.08.125
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