Mailing: 13 April 2012

CCAFS report: Achieving food security in the face of climate change

Beddington J, Asaduzzaman M, Fernandez A, Clark M, Guillou M, Jahn M, Erda L, Mamo T, Van Bo N, Nobre CA, Scholes R, Sharma R, Wakhungu J. 2011. Achieving food security in the face of climate change: Summary for policy makers from the Commission on Sustainable Agriculture and Climate Change. CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS). Copenhagen, Denmark.

This report by the Commission on Sustainable Agriculture and Climate Change (CCAFS) reviews the scientific evidence to identify a pathway to achieving food security in the context of climate change. It says that food systems must shift to better meet human needs and, in the long term, balance with planetary resources. This will demand major interventions, at local to global scales, to transform current patterns of food production, distribution and consumption. Investment, innovation, and deliberate effort to empower the world's most vulnerable populations will be required to construct a global food system that adapts to climate change and ensures food security while minimizing greenhouse gas emissions and sustaining our natural resource base. Greatly expanded investments in sustainable agriculture, including improving supporting infrastructure and restoring degraded ecosystems, are an essential component of long-term economic development. The sooner they are made, the greater the benefits will be.

The report identifies 5 essential changes that are needed to achieve food security in the face of climate change.  These are to:

  • Reduce GHG emissions from agriculture
  • Adapt to climate change
  • Change diets towards more plant-based foods
  • Reduce waste
  • Improve crop yields.

(NB: Note that a growing number of scientists and policy observers a starting to underline exactly the same points – see for example the Government’s Foresight report, and a paper published in Nature in 2011 by Foley et al  to name but a few).


The report makes seven recommendations designed to be implemented concurrently by a constellation of governments, international institutions, investors, agricultural producers, consumers, food companies and researchers. They focus on the need for changes in policy, finance, agricultural production, development aid, diet choices and food waste as well as revitalized investment in the knowledge systems to support these changes. In brief the recommendations are to:

  1. Integrate food security and sustainable agriculture into global and national policies
  2. Significantly raise the level of global investment in sustainable agriculture and food systems in the next decade
  3. Sustainably intensify agricultural production while reducing greenhouse gas emissions and other negative environmental impacts of agriculture
  4. Develop specific programmes and policies to assst populations and sectors that are most vulnerable to climate changes and food insecurity
  5. Reshape food access and consumption patterns to ensure basic nutritional needs are met and to foster healthy and sustainable eating patterns worldwide
  6. Reduce loss and waste in food systems, targeting infrastructure, farming practices,  processing,distribution and household habits
  7. Create comprehensive, shared, integrated information systems that encompass human andecological dimensions

The report, including a summary for policy makers in various languages, is available here.  You can also find an overview here, together with a useful 6 minute animation that outlines the problem and sumarises the changes needed.

Presentation: Scenarios of improved agriculture efficiencies and diet modification consistent with representative concentration pathways (RCPs) of nitrous oxide

This is an interesting presentation, given by Eric Davidson of Woods Hole Research Center, at the recent Planet under Pressure conference in March 2012.  The presentation is a summary of a paper he has forthcoming in Environmental Research Letters (which I will circulate in due course). It makes the point that reducing N2O emissions isn’t a question of focusing on dietary change OR on technological improvements – both are needed if stabilisation of atmospheric N2O is to be achieved.

Abstract of presentation as follows:

Atmospheric concentrations of nitrous oxide (N2O) have been increasing since the Industrial Revolution, as livestock herds increased globally and as the use of synthetic-N fertilizers increased after WWII. Significantly reducing those emissions while also improving the diets of the growing global human population will be very challenging. Increases in atmospheric N2O since 1860 are consistent with emissions factors of 2.5% of annual fertilizer-N usage and 2.0% of annual manure-N production being converted to N2O. These factors include both direct and indirect emissions attributable to these sources. Here I present projections of N2O emissions for the following scenarios: (1) FAO population/diet scenarios with no changes in emission factors; (2) per-capita protein consumption in the developed world declines to 1980 levels by 2030 and only half of that is obtained from animal products; (3) improvements in N-use efficiency and manure management reduce the emission factors by 50% by 2050; (4) same as 3 but industrial and transportation emissions are similarly reduced by 50% by 2050; and (5) all mitigations together. These projections are compared to the four representative concentration pathways (RCPs) developed for the IPCC-AR5. With no further mitigation, the projections are consistent with RCP8.5, with atmospheric N2O at 368 ppb in 2050. Major reductions in per-capita meat consumption in the developed world reduce projected 2050 N2O to 356 ppb, which is in line with RCP6.0. Cutting emission factors in half but without diet change would also lower projected 2050 N2O to 352ppb. Adding 50% improvements in other sectors reduces the 2050 N2O to 350ppm, which is in line with RCP4.5. Only by combining these improved efficiencies with reduced meat consumption can the most optimistic scenario of RCP3PD be achieved, with stabilization of atmospheric N2O at about 341 ppb in 2050.


You can download the presentation here. Some of the other output from the event can be found here.

Report: Geographical extrapolation of environmental impact of crops by the MEXALCA method

Nemecek T, Wiler K, Plassman K and Schnetzer J (2012). Geographical extrapolation of environmental impact of crops by the MEXALCA method, Unilever-ART project no. CH-2009-0362 “Carbon and Water Data for Bio-based Ingredients”: final report of phase 2: Application of the Method and Results,

This interesting study, commissioned by Unilever presents the range of GWP (global warming potential) values for 27 crops grown worldwide, looking both at the variability of values for the same crop across countries as well as differences between crops.  The work is based on the use of the MEXALCA method -modular extrapolation of agricultural life cycle assessment. MEXALCA is an extrapolation method for LCA data of conventional crop production. Its basic concept is to carry out a life cycle inventory (LCI) and life cycle impact assessment (LCIA) and LCIA for a particular crop production system in one country (origin country) with good data availability. The LCI and LCIA for crop production corresponding to all crop producing(target) countries worldwide can then be assessed by an extrapolation method.  The results are validated against data from ecoinvent and the literature.The model is amended in this study to partly include land use change impacts – ie. above- ground but not below-ground carbon losses which means that land use change effects for some crops are underestimated..

The crops the study considers are: Rape seed; Soya beans; Oil palm; Sugar cane; Sugar Beet; Wheat; Barley; Rye; Rice ; Maize; Cotton fibers and seed; Peanuts; Linseed; Peaches; Apples; Bananas; Oranges; Potatoes; Carrots; Spinach; Onions; Pumpkins; Bell peppers; Tomatoes; Peas; Almonds; Hazelnuts.

This report finds that the weighted worldwide means of GWP values of the studied crops varied across a wide range (factor of 20 per hectare, factor of 100 per kg of product). The lowest GWP values per kg of fresh mass (without considering land use change) were found for the sugar crops with high yields (sugarcane and sugarbeet), followed by root crops (carrot, potato), fruits, vegetables and oil palm. Cereals (except rice), pulses, rapeseed and soybean had medium GWP values. High values were found for treenuts, the oil crops (linseed, cotton, peanuts), and rice.

Fruits, vegetables and cereals (except rice) each formed relatively homogeneous groups with widely overlapping ranges. The same holds for the sugar crops and root crops. Treenuts seem to have relatively similar values, but only two species were included in the study. Oil crops are a very inhomogeneous group including oil palm with low GWP, rapeseed with medium values and linseed, cotton and peanuts with high values.

The GWP was dominated by N fertilisers and nitrogenous emissions, energy use for irrigation, use of the machinery and carbon losses following land use change. The relative contribution of the different modules varied widely between the crops.

The yield and the farming intensity in the different countries (as expressed by the agricultural indices) were found to be relevant factors for the variability of GWP. The GWP values varied more per area than per kg, except for the crops, where the area-related impacts dominated (rice, pea). The variability of GWP increased with its magnitude, which led to relatively constant coefficients of variation. When the impacts of different crops were compared, no relationship per ha was found, but the GWP tended to decrease per kg with higher yields. The highest yields are achieved for crops with high water contents in the harvested products, like vegetables, fruits, roots and sugar crops. The comparison of the production of the same crop in different countries showed an increasing tendency of GWP per ha with higher yields, which is explained by a higher production intensity. There was in general no relationship for the GWP per kg. The selection of the producing countries was found to have a dominant effect on the variability of GWP. Crops that are produced in a few countries only and crops with homogeneous production conditions tend to have a low variability of GWP.

Two figures from the report that may be of interest are as follows:



Further factors that were not considered in this study are also expected to contribute to the variability of GWP: different farming systems, differences in input use, pedo-climatic conditions, variability of the production within a country, and land use change impacts.

An analysis performed on regionally grouped countries (grouping by development level, and part of continents) showed that the yields generally increase in the order least developed countries (LDC), developing and developed countries. The GWP per ha (average of relative values of all studied crops) showed the same trend without consideration of the deforestation. Inclusion of deforestation almost compensated the differences between the development levels. GWP per kg was highest in developing countries, followed by developed and LDC with deforestation. With the inclusion of deforestation, it increased in the order developed < developing < LDC; i.e. the finding suggests that the currently observed deforestation is linked to low level of development.

A principal component analysis showed the similarities and different between the environmental profiles of the studied crops. It seems difficult to derive general rules to group similar crops together. Cereals (without rice), sugar crops (sugar cane and sugarbeet), and tuber and root crops were relatively similar, while oil crops formed a very inhomogeneous group. A lot of variation was found within fruits and vegetables, however clear subgroups could not be identified. Tree nuts seem to be quite different from other crops.

Options for future development of the model include: using more robust irrigation data, combining several original inventories in order to reduce the dependency on a single original inventory, or the inclusion of crop specific data in the agricultural indices and the input estimators, in order to assess better the farming practices of the individual crops.

The report is available here.


The science journal article related to the report can be found here: Nemecek T, Weiler K, Plassmann K, Schnetzer J, Gaillard G, Jefferies D, García–Suárez T, King H, Milà i Canals L (2012) Estimation of the variability in global warming potential of global crop production using a modular extrapolation approach (MEXALCA) J Cleaner Prod 31 106-117 DOI:10.1016/j.jclepro.2012.03.005

A journal article explaining the method, published in 2010, is available here: Roches A, Nemecek T, Gaillard G, Plassmann K, Sim S, King H, Milà i Canals L (2010) MEXALCA: A modular method for the extrapolation of crop LCA. Int J Life Cycle Assess 15(8) 842-854 DOI:10.1007/s11367-010-0209-y

Journal paper: comparison of organic and conventional farming systems in California

Venkat K (2012). Comparison of Twelve Organic and Conventional Farming Systems: A Life Cycle Greenhouse Gas Emissions Perspective, Journal of Sustainable Agriculture 10.1080/10440046.2012.672378

The goals of this study were to: (a) develop a robust, model-based life-cycle GHG emissions comparison of organic and conventional farming methods for a relatively large selection of crop products; (b) use the best available production data for these crops from specific agricultural regions in the United States, including information on management practices; and (c) account for the effects of soil carbon sequestration in relevant farming systems taking into account the climate zone, moisture regime and soil type for the geographical regions.


Given the growing importance of organic food production, there is a pressing need to understand the relative environmental impacts of organic and conventional farming methods. This study applies standards-based life cycle assessment to compare the cradle-to-farm gate greenhouse gas emissions of 12 crop products grown in California using both organic and conventional methods. In addition to analyzing steady-state scenarios in which the soil organic carbon stocks are at equilibrium, this study models a hypothetical scenario of converting each conventional farming system to a corresponding organic system and examines the impact of soil carbon sequestration during the transition. The results show that steady-state organic production has higher emissions per kg than conventional production in seven out of the 12 cases (10.6% higher overall, excluding one outlier). Transitional organic production performs better, generating lower emissions than conventional production in seven cases (17.7% lower overall) and 22.3% lower emissions than steady-state organic. The results demonstrate that converting additional cropland to organic production may offer significant GHG reduction opportunities over the next few decades by way of increasing the soil organic carbon stocks during the transition. Non-organic systems could also improve their environmental performance by adopting management practices to increase soil organic carbon stocks.


This study compares the environmental impacts of 12 distinct crop products that are grown in the agricultural regions of California using both conventional and organic methods. Using publicly available agricultural production data for these crops, it applies standards-based LCA techniques to compare the cradle-to-farm gate GHG emissions per kg of each crop product grown using each production method. In addition to analyzing baseline steady-state scenarios in which the SOC stock is at equilibrium in both the conventional and organic systems, this study models a hypothetical scenario of converting each conventional farming system to a corresponding organic system and examines the impact of soil carbon sequestration during the transition. In order to accomplish this last part, the study establishes the climate zone, moisture regime, soil type, land use, and management practices for each of the conventional and organic farming systems.

Of the 12 crop products, steady-state organic production has lower GHG emissions in only five cases. Steady-state conventional production has the lower emissions in the other seven cases. Average emissions for steady-state organic production are higher by 10.6% (excluding walnuts as an outlier). The reasons for this vary, including: lower yields and higher on-farm energy use in organic farming, the production and delivery of large quantities of compost or manure to organic farms, and the fact that emissions from the manufacture of synthetic fertilizers and pesticides used in conventional farming are not large enough to offset the additional emissions in organic farming.

Transitional organic production fares better than steady-state organic production. It generates lower GHG emissions than steady-state conventional production in seven cases, and 17.7% lower emissions on average (excluding walnuts). It also generates lower emissions than steady-state organic production in all but one case where they generate equal emissions. Soil carbon sequestration drives the emissions for transitional organic production lower by an average of 23.2% compared to steady-state organic production. The results demonstrate, within the limitations of the data and the modeling, that converting additional cropland to organic production over the next few decades may offer significant GHG reduction opportunities by way of increasing the SOC stocks during the transition. If those higher levels of carbon stocks can be maintained in the soil over the long term (as assumed in this study), then converting to organic production may indeed prove to be an important tool in the mitigation of climate change. The results also suggest the possibility that some non-organic farming systems may be able to improve their environmental performance by adopting practices to increase soil carbon stocks without entirely switching to organic methods.

NB: This study, like the MEXALCA study also finds treenuts to have very high GWP values, which I found surprising.

You can download the paper here (subscription access only). Alternatively you might want to contact the author, Kumar Venkat, who’s an FCRN mailing list member via the FCRN user pages (you’ll need to log in to do so).

McDonald's launches farming project

McDonald's has launched a long term programme to support British and Irish farmers, with efforts to boost the number of young people in the industry and improve environmental and animal welfare standards.

With an initial first-year investment of £1 million, Farm Forward is built around five core commitments that span: quality of ingredients; animal welfare standards; creating work and training opportunities for young farmers; environmental and efficiency standards; and knowledge sharing. The programme has been created in collaboration with leading farmers and agricultural experts including the National Farm Research Unit, beef and lamb industry organisation EBLEX and FAI Farms.

The programme will include:

  • A training programme for young farmers, which will enable agricultural students from across the UK to complete a 12 month placement to gain experience through the whole spectrum of the agricultural supply chain, from farm to abattoir to restaurant.
  • A free simple carbon calculator to help livestock farmers measure and understand how to change their working practices in order to drive greater efficiencies on their farms and improve environmental performance.
  • Funding new research and innovation to encourage improvements in animal welfare standards by providing evidence and practical guidance for farmers.

To read the McDonalds press release see here.

DECC provisional UK GHG estimates - 2011

The Department of Energy and Climate Change has published its provisional 2011 estimates of UK greenhouse gas emissions, together with final estimates of 2010 UK greenhouse gas emissions by fuel type and end-user. It finds that in In 2011, UK emissions of the basket of six greenhouse gases covered by the Kyoto Protocol were provisionally estimated to be 549.3 million tonnes carbon dioxide equivalent, 7.0 per cent lower than the 2010 figure of 590.4 million tonnes.  Note that these are emissions generated within UK borders - UK consumption emissions (ie. taking account the embedded emissions in imported goods, and excluding those embedded in exports) are 34% higher than production emissions, and are growing. See here for more.

Going back to the DECC estimates, agricultural emissions in 2010 (2011 figures are not yet available) seem to have increased slightly over 2009.  See here for more information.