Climate and war

I’m working on a paper evaluating climate and temporal trends on feed supply for livestock production. One of my co-authors suggested including a thought on climate-induced instability and conflict as an important factor affecting rangeland feed utilization. So, I have finally taken a look at this recent literature and see there is a heated debate being conducted on the issue of Climate and war.

One camp believes that the data demonstrate a clear linkage between incidence of civil war and temperature
(Burke et al. 2009). Others cite the importance of other factors unrelated to climate (Sutton et al. 2010) or use different data to demonstrate no linkage (Buhaug 2010a) – plus stern back and forth in PNAS letters (Burke et al. 2010a, b; Buhaug 2010b). This issue has received quite a bit of attention – in Nature, the Economist, etc. Defining Civil war is not easy. Nor is understanding its causes.

Buhaug H (2010a) Climate not to blame for African civil wars. Proceedings of the National Academy of Sciences of the United States of America, 107, 16477-16482.

Buhaug H Reply to Burke et al.: (2010b) Bias and climate war research. Proceedings of the National Academy of Sciences of the United States of America, 107, E186-E187.

Burke MB, Miguel E, Satyanath S, Dykema JA, Lobell DB (2009) Warming increases the risk of civil war in Africa. Proceedings of the National Academy of Sciences of the United States of America, 106, 20670-20674.

Burke MB, Miguel E, Satyanath S, Dykema JA, Lobell DB (2010a) Climate robustly linked to African civil war. Proceedings of the National Academy of Sciences of the United States of America, 107, E185-E185.

Burke MB, Miguel E, Satyanath S, Dykema JA, Lobell DB (2010b) Reply to Sutton et al.: Relationship between temperature and conflict is robust. Proceedings of the National Academy of Sciences of the United States of America, 107, E103-E103.

Sutton AE, Dohn J, Loyd K et al. 2010. Does warming increase the risk of civil war in Africa? Proceedings of the National Academy of Sciences of the United States of America, 107, E102-E102.

Nitrogen and grain production in Malawi

Snapp et al. have an interesting article in today’s issue of PNAS: Snapp SS, Blackie MJ, Gilbert RA, Bezner-Kerr R, Kanyama-Phiri GY (2010) Biodiversity can support a greener revolution in Africa (107, 20840-20845). They find that diverse crop rotations that include legumes (either in rotation or inter-cropping) can enhance the net production benefits of fertilizer – increasing production and fertilizer use efficiency using technologies preferred by Malawian producers. (BTW, Africa is much bigger than Malawi).

One test used to assess sustainability is a “Value Cost Ratio” that indicates returns. Snapp et al. found that returns were greater for the low fertilizer-input systems. Not surprisingly, they find that these systems respond better to a doubling of fertilizer prices relative to yields. This has not quite happened with US prices over the past 10 years, but fertilizer prices have more than doubled while grain yields have increased by 50%.

This article takes a step toward understanding nitrogen dynamics toward understanding how to increase production in nutrient-poor systems. However, because they didn’t include any information on N inputs from these different sources, it’s hard to know how efficient (and sustainable) they are. The metric they use “fertilizer efficiency” is faulty because it considers the costs of just one source of N inputs and fails to account for the most important aspect of nutrient sustainability – the supply of soil-mineralized N.

Two criticisms of the article. First, their focus on ecosystems services isn’t very comprehensive. VCR and fertilizer use efficiency are not ecosystem services. Second, this article is not about biodiversity. There are important differences in these crop rotations, but none of the systems foster preservation of native biodiversity.

I’m grateful to the authors for pointing me toward the 2000 article by Borlaug defending biotechnology in agriculture (Borlaug NE (2000) Ending World Hunger. The Promise of Biotechnology and the Threat of Antiscience Zealotry. 124, 487-490).

Emissions from food production

Some of my colleagues based at the Animal Production and Health Division at the UN Food and Agricultural Organization are doing some very interesting work on emission from a variety of livestock-based food production sectors. They recently released a report on emissions from the dairy sector that is interesting for a few reasons.

The report relies upon quite a diverse set of data from a variety of sources. Integrating these data in a meaningful way is a real challenge. For example, how to attribute CO2 emissions associated with land use change to specific  deforestation? One approach might be to attribute this evenly to all dairy products on the assumption that all products contribute to meeting global demand for dairy products. The approach taken here is different: they attributed deforestation-related emissions according to use of soybean cakes for feed because soybean production in areas that were formerly forests , shrublands, or pastures. Similarly, how to attribute emissions from draft animals contributing to dairy feed stocks knowing that they provide traction and meat products? How to allocate calves to dairy production?

Emissions (to the farm gate) associated with milk production amount to about 3% of total emissions while emissions associated with important dairy sector meat by-products (from slaughtered cows, bulls, and surplus calves) contribute about half that much again (541 Mt CO2-e; 1.3% of total emissions). Everywhere in the world the bulk of the emissions arise from milk production (versus transportation and deforestation).

The variation in the GHG efficiency of milk production (emissions per unit product) is remarkable – varying from ~1.2 kgCO2 per kg milk in N America and Europe to over 7 in sub-Saharan Africa! It is well-established that the much more input-intensive systems in the developed world are more productive than the subsistence production systems more common in the developing world. This work clearly shows that they are much less emission intensive as well – increases in production outweighing increases in inputs.

The group is preparing similar reports for other sectors – stay tuned!

The Kaya identity – and agriculture

If you haven’t seen it yet, take a look at Roger Pielke Jr’s latest book: The Climate Fix. It’s a great read. In working with Roger in the past, I am particularly grateful to him for introducing me to the Kaya identity. In the Climate Fix he does a nice job of deriving it, explaining it, and exploring the implications. Simply put,

CO2 emissions = population  × GDP/person × Energy/GDP × CO2/Energy

A rise or fall in population or one of the other factors (affluence, energy intensity, or carbon intensity) leads to a corresponding change in emissions. One of the few papers published on this topic (Waggoner and Ausubel 2002) does a very good job of explaining historical trends and there is some discussion about food production. Waggoner and Ausubel identify energy intensity (energy/GDP) and carbon intensity (CO2/energy) as  “sustainability levers.” This framework does an excellent job of helping us understand drivers and potential solutions for CO2 emissions. However, I would argue that their food example is squeezed into the framework in a manner that confuses rather than clarifies the issue of greenhouse gas emissions from agriculture. This confusion is reflected in their discussion about how to integrate changes in dietary preference into the identity as one efficiency factor (meat consumption per capita) or another (meat produce per unit feed).

I propose an alternative formulation of the Kaya Identity that is more directly consistent with food production and greenhouse gas emissions from agricultural systems.

GHG emissions = population  × food/person × land/food × inputs/land × GHG/input

Some notes:

-This identity can be used to understand drivers of CO2, N2O, and (substituting “animals” for “inputs”) CH4 emissions.

-The first two terms (population and food consumption/person)  are directly analogous to those of the Kaya Identity.

-The third term (land use intensity – land area divided by food production) is the inverse of yield (food production per unit land area). This term is unique to the identity developed here, but is central to agricultural research and is recognized as a means to reduce greenhouse gas emission (see Burney et a. 2010; PNAS 107:12052).

-Inputs include nitrogen, pesticides, water, energy etc. comprise the agronomic efficiency term (the fourth term), demonstrating that reducing inputs reduces emission. Implicit in these third and fourth terms are the tradeoffs between intensification of land and the GHG costs for doing so.

-This formulation does not explicitly recognize carbon sequestraiton, but I am currently collaborating with colleagues from Princeton and IIASA to do so through the land use intensity term.

-This modified Kaya Identity integrates standard ecological concepts that align with different avenues of agricultural research and enable clear interpretation of discussions about the benefits and detriments of reducing emission from agriculture or selecting between competing visions for agricultural production systems. I will use this framework frequently in subsequent discussions.

US Agriculture: Policy opportunities for increasing soil sustainability

The world’s soils are sitting in a unique position with respect to the challenging environmental issues of the anthropocene. They are increasingly under threat from desertification, extreme weather events and land use change, but can also be managed to ameliorate global problems that contribute to such threats. This is both the good and bad news. The especially good news, however, is that there is tremendous potential for creating policy that addresses both of these issues in a way that additionally benefits producers financially. Win-win situations like this are rare…are we so used to the complex, tricky-to-solve problems that we assume they all fall into that category?

US policy has taken several steps in the past two decades to encourage the sustainable use of soils, yet there are still a number of improvements to be made. An article published earlier this year from the A.F.T.’s Center for Agriculture and the Environment does an excellent job of summarizing the background of US agricultural policy and current status, and relates scientific information that might further these policy goals. Identifying key areas in need of attention, the article suggests policy tactics that would help reduce both local and global environmental impacts of agriculture (including impacts on soil itself), while simultaneously increasing both ecosystem services and economic benefits provided by these lands. The article makes a great case (verging on a plea) for more serious recognition of these concerns and potentials, in light of the increasing necessity to be addressed.  Delivering the co-benefits of sustainable soil management through enhancing agricultural policy seems like a no-brainer to me, but check it out and see what you think.

*There is also a wealth of additional information as well as reports (no subscription required, in case you don’t have access to the above article) surrounding this topic on the American Farmland Trust Center for Agriculture in the Environment website.

Rising global interest in farmland

The World Bank has released a report (Rising Global Interest in Farmland: Can it yield sustainable and equitable benefits?) reviewing recent transactions involving large farmland acreages. Justification for the report stems from lack of information about the scope and impact of such transactions and the growing demand for land – citing 45Mha of deals in 2009 compared with 4Mha in 2008 and a forecast of 6Mha converted per year, most in Latin America and sub-Saharan Africa.

Of course the worry is that transfer of control over these lands – through ownership, lease, or production contracts – will not benefit the local populace who often are predominantly dependent upon the land. The report re-affirms “Principles for responsible agro-investment” created by the World Bank, FAO, IFAD, and UNCTAD:

1. respect land and resource rights
2. ensure food security
3. ensure transparency, good governance, and a proper enabling environment
4. consultation and participation
5. responsible agro-investing (rule of law, best practices, durable shared value)
6. social sustainability
7. environmental sustainability

An interesting point in the report is that “large increases in output and welfare for the poorest groups could be possible” even without agricultural expansion – i.e., through intensification and bridging the yield gap. Is this in conflict with the sentiment that “one of the highest development priorities in the world must be to improve smallholder agricultural productivity”? I don’t know the answer to this question, but it is central to discussion about agricultural development and will be an ongoing theme in this blog. This report contains an interesting discussion (section 1.3) on economic factors that lead to family-owned, small farms, factors that drive farm consolidation, and barriers to agricultural development that stem from this.

Soil erosion impacts on biogeochemistry

In the recent Nature Geoscience issue focused on soils, Quinton et al. have a very nice article on soil erosion impacts on the C, N, and P cycles. It is a “Progress article,” intended to describe the state of the science. This Progress Article is much briefer than a review article and the language seems intended for a broader audience than most reviews. It reads like a short section of a text book – but of course it is up-to-date. It’s a nice idea.

The article reviews studies that have examined erosion rates, and the fate of C, N, and P in eroded material. This is an important topic, with studies speculating that erosion could lead to a significant sink or source of CO2. The article presents an interesting framework diagram that emphasizes the dynamic nature of erosion – it removes organic matter and changes the conditions for replacing that organic matter. The estimate of N lost from erosion is staggering: 23-42 Tg N yr-1. As they say, this is on the same order of magnitude as N harvested in crops. That means that we are unintentionally losing as much N from our cropland soils as we are collecting through harvest. Wow.

The methods used for this work seem reasonable and serve as a nice description of a rationale way to assimilate data from diverse sources.

“Soil is one of the most precious resources on the planet.”

“The precise impact of land use on soil biodiversity, element cycling and the ability of the soils to support life is one of the gaping holes in our understanding of soils.”

The most recent version of Nature Geoscience (Volume 3, Issue 5; here) has a series of very good soil-related articles, including a letter on soil moisture monitoring (Dolman and de Jeu), commentaries on soil biodiversity (Wall, Bardgett, and Kelly) and soils/food (Sanchez), a review of a new book (Soils and culture; review by Josh Schimel), two focus pieces (weathering and arctic thaw), and research letters on erosion, soil respiration, nitrous oxide emissions, and temperature controls on decomposition. There is also a really nice “backstory” on sampling in an extreme environment – the most saline pond on earth! Interestingly, they found rates of abiotic N2O emissions comparable to rates of  biotic N2O production from fertilized soils.

I will discuss several of these articles this week. But before I do that, an idea in the the editorial that introduces these stories caught my attention. It asserts that soil is a precious resource and one that is increasingly sought after. Over the past year and half there have been several stories on poor developing countries leasing land to agribusinesses or rich countries to produce food. This is a contentious issue for a variety of reasons, some of them are covered in this article from the New York Times last year. There has been much talk about bringing the green revolution to Africa, but increasing production for export first is not usually part of the equation.  Is leasing agricultural land to produce good for export justifiable in countries where millions of people are malnourished? Paul Collier makes the case (subscription required) that increasing supply is the only feasible way to deal with rising food prices. And the way to do that is to increase commercialization of agriculture, employ all technologies that foster increased food production (i.e., GMOs), and eliminate subsidies for biofuels. It will be interesting to see how this plays out over the coming years. An important metric will be the link between growth in food production and declining hunger.

About this blog…

Many have waxed eloquently about the importance of soil (e.g., “The nation that destroys its soil destroys itself” — FDR) or lamented our lack of knowledge about the soil (“We know more about the movement of celestial bodies than about the soil underfoot.” — Leonardo daVinci).

Plan to see a lot of both on this blog!

My goal here is to present the latest scientific information and my thoughts on how that new knowledge fits in with – or contradicts – what we already know. I also want to foster discussion about that new soil science knowledge means for environmental sustainability and human well-being. Soils are at once integrators of diverse ecosystem processes and a fundamental resource that is often taken for granted. We know quite a bit about the world under our feet, but there is still a lot to learn. I hope that this blog facilitates that.

This blog follows fast on the heals of a release of a new documentary – DIRT! The Movie. I haven’t seen it, but I did read the excellent book that was it’s basis: Dirt: the ecstatic skin of the Earth. It is a really good read. It is especially interesting to think about how soil shapes major events like the US civil war. To learn more, visit the PBS DIRT! web site or check out the book from your local library.

Hello world!

Welcome to the Global Soil Sustainability Working Group’s blog.  We will use this space as a forum for discussion on important issues relating to research, communication and outreach pertaining to soil sustainability.

The mission of the Global Soil Sustainability Working Group is to leverage the diverse strengths of Colorado State University scientists by coordinating research activities and providing a platform that integrates soil data from disparate sources to facilitate more productive interaction between soil scientists and decision-makers.

Our goal is bring the information revolution to soil science. We aim to transform the information topology of soil science by integrating disparate data, enabling scientists to devote time to testing theories and advancing knowledge. The purpose of this research working group better integrate soils-related expertise at Colorado State University, to enhance coordination of soils research at US land grant institutions, and to facilitate more fruitful interaction between soil scientists and decision-makers. Our initial focus is on two vitally important areas in which CSU scientists already possess world-class expertise: carbon management and soil fertility.

Please visit our webpage at http://globalsoils.colostate.edu.

For more information on the sustainability research going on at Colorado State University, please visit the School of Global Environmental Sustainability at http://soges.colostate.edu.