Rethinking Biofuels: Alternative Feedstocks Switchgrass and Miscanthus Predicted to Outperform Corn Grain

            Concerns over the potential effects of climate change on energy and food production in the last ten years have created a new market for alternative fuels.  In the United States, corn-based ethanol, likely due to the political clout of the US corn lobby, has dominated biofuels research to date.  However, corn may be ill-suited for ethanol production because oil is used in the production, transport, and application of the large amounts of nitrogen fertilizer necessary to boost corn yields.  The nitrogen fertilizers have a detrimental effect on the environment by decreasing soil productivity and leaching into neighboring soils and water tables.  With the advent of the US Energy Independence Act of 2007, the US government created demand for up to 15 billion gallons of corn derived ethanol per year, mandating any amount beyond that be produced from other feedstock sources.  Although high in energy yield, corn’s dependence on oil makes it less efficient overall if environmental damage and GHG emissions are considered.  The cap on corn ethanol production initially stimulated research into alternative feedstock, with preliminary research showing great promise from perennial grasses like switchgrass and miscanthus.  The initial studies on the relative energy yield efficiency of corn and alternative feedstock prompted Parton et al. to develop a model capable of estimating the benefits of switching ethanol feedstock from corn to perennials.  By using regression analysis of the DAYCENT model, they found that by substituting miscanthus and switchgrass for corn on lands already designated for ethanol production food productivity would increase by 4% and available feedstock for ethanol by 82% all while avoiding the GHG releases associated with the conversion of uncultivated land for agricultural production (known as ILUC, indirect land-use change).—Michael Gazeley-Romney
Davis, S., Parton, W., Del Grosso, S., Keough, C., Marx, E., Adler, P., DeLucia, E., 2011. “Impact of second-generation biofuel agriculture on greenhouse-gas emissions in the corn-growing regions of the US”. Frontiers in Ecology and the Environment; doi:10.1890/110003

            Davis et al. simulated the effects of substituting 30% of the central US regional corn crop with three alternative biofuel crops: (1) switchgrass, (2) switchgrass with fertilizer treatments, and (3) miscanthus.  Using the model they were able to calculate the feedstock production potential in each case as well as related GHG emissions, soil carbon sequestration, and nitrogen leaching over a ten year period.  Their model is version of the CENTURY model that operates on a daily time step simulating exchanges between soil, plants, and the atmosphere as well as the affects of management practices like prescribed burning, grazing, and fertilizer use.  To verify the accuracy of the model, the simulations were compared to test results from biofuel feedstock test plots already present in the study region finding close correlations for crop yields, GHG emissions, and nitrogen leaching.  Using a simulation of ethanol corn production as a baseline, the researchers were able to calculate the differences in outputs between the growth scenarios.
          Possible imperfections in the model stem from the unknown effects of ILUC on GHG emissions.  Although it is generally understood that large amounts of GHGs are produced in the tilling of virgin soil for agriculture, the amounts are hard to predict and can vary greatly.  In order to compensate for this, Davis et al. calculated the effects of converting 30% of central US corn acreage to ethanol production using ILUC accounting from the California Air Resources Board finding emissions of 4.7–5.3 Tg C.  When computed with the model results, the ILUC emissions did not have a significant effect on the large net differences between emissions for corn and those for the perennials.  This is significant because the ILUC calculations should not apply to the test scenarios as no new land is being converted; the crops are simply being rotated.  Controversy over outcrossing and slow investment realization (three years needed to establish perennial grass crops) are also omitted from the model analysis.  However, both switchgrass and miscanthus present a low outcrossing risk because switchgrass is native to the US and miscanthus is a sterile hybrid.
          The results of the modeling showed significant environmental benefits from switching to perennial cellulose feedstock.  These findings are more significant because the model was constructed to only consider the conversion of land already being used in ethanol production.  In this way, the environmental benefits realized by switching feedstock crops comes absent the usual concerns about ethanol land use competing with food production.  By limiting the model to a 30% corn-to-perennial land-use switch, the researchers hoped to simulate the complete transition from corn to perennial feedstock in US ethanol production (30% of all corn grown in the US is used in ethanol production).  By avoiding the effects of ILUC entirely and only substituting feedstock within the existing production capacity of 30%, the study reduces foreseeable land use pressure from ethanol production on the 8% of US corn grown for food. 
          Modeling of soil organic carbon (SOC) showed increases under fertilized switchgrass and miscanthus cultivation of 27 and 173 Tg Ceq yr-1 respectively.  Compared to corn, fertilized switchgrass increased SOC by 1.9% and miscanthus by 19%.  The conversion from corn to perennial feedstock changed also altered the regional output of GHGs–in terms of the re-appropriated cropland–from 27 Tg Ceq yr–1 for corn to 17 Tg Ceq yr–1 for switchgrass, –0.05 Tg Ceq yr–1 for fertilized switchgrass, and –97 Tg Ceq yr–1 for miscanthus.  While the switchgrass succeeded in reducing agricultural GHG emissions, the substitution of miscanthus effectively transformed the entire region into a massive carbon sink.  Davis et al. attributed the reduction in GHG emissions to less fertilizer use and increased carbon sequestration in the perennial crops compared to corn.  Davis et al. reinforce the magnitude of this finding by citing a recent study that shows the reduction in GHGs from ethanol use (in the place of fossil fuel) are wholly offset by the heavy application of nitrogen fertilizers on corn.
          Using other research to interpret the significance of the modeling results, Davis et al. found that switching to perennial grasses would reduce nitrogen use overall, resulting in 0.7–0.8 Tg N yr–1 less nitrogen leaching through the soil.  With 52% of the nitrogen polluting the Gulf of Mexico stemming from US corn and soybean production, the savings on environmental mitigation measures in the Gulf alone would be significant.  To further demonstrate the relative benefits of switching feedstock, the researchers calculated the CO2 emissions from harvests of the corn and grasses, with the grasses producing 74% less CO2 during the harvest cycle.
In a second run, Davis et al. altered the model constraints to substitute the perennials for corn on only the least productive 30% of the ethanol corn grown in the region.  In this model the differences in efficiencies between corn and the perennials were even more pronounced with miscanthus producing 82% more biomass for ethanol feedstock than the corn baseline scenario, the equivalent of about twelve billion gallons of ethanol.
As we continue to wean ourselves from foreign oil, energy efficiency within national production systems will take on a higher priority for policy makers.  Choosing a low N-input, high energy-output feedstock over traditional corn has been shown under comprehensive modeling by Davis et al. to be much more efficient.  When considering biofuels, it cannot be forgotten that they are meant to be a low-impact replacement for fossil fuels.  With its dependence on oil for growth in the current agricultural system, corn has become an unsuitable and highly inefficient ethanol feedstock compared to perennial grasses.  The findings of the study with regard to the yield efficiency and environmental benefits of miscanthus make it the clear choice for future feedstock use.  In light of the findings of Davis et al., national production capacity for cellulose feedstock like miscanthus needs to be addressed in order to realize its benefits.  Replacing corn ethanol feedstock in the central US region could increase the regional productivity of food by 4% and feedstock biomass 82% all while avoiding additional ILUC, making ethanol a truly environmentally friendly substitute to fossil fuel.

The Global Oil Economy: Forecasting the Role of Nutrient Use Efficiency in Agricultural Development

There is no question of the importance of oil in the global economy.  The United States is currently involved in two separate conflicts for reasons most analysts and policy makers attribute to national demand for cheap oil.  The Iraq war, at an estimated cost of between 2.7 and 5 trillion US dollars and 90,000 and 800,000 civilian lives, illustrates the lengths policy makers will go to secure oil reserves.  With the rest of the world producing the majority of the world’s crude and 60% of the 500 biggest fields already at peak production, energy use efficiency is now more important to national security than ever.  As one of the world’s largest agricultural producers, the ability of the United States to cheaply and efficiently produce food has a direct effect on the price of food worldwide.  With the predicted increases in population, storm severity, and food insecurity due to climate change the pressures being placed on US commercial agricultural systems will continue to increase rapidly.  In response to concerns about US dependence on foreign oil sources, the U.S. Energy and Independence and Security Act of 2007 now mandates biofuel output requirements for the national economy.  The U.S. Air Force, the world’s greatest consumer of petroleum has also announced plans to increase its use of biofuels to 50% in an effort to reduce their reliance on foreign oil.  National security and climate change policies have made biofuels a clear priority for the U.S. economy.  Due to competition from biofuels, the amount of arable land available for food production will likely diminish in the future.  Since oil is used in the production, transport, manufacture, and application of the nitrogen fertilizers used in commercial agriculture, current and future market pressures have produced an environment where increasing nutrient use efficiency is not only necessary, but cost effective.—Michael Gazeley-Romney
Liska, Adam J. and Perrin, Richard K., 2011. “Energy and Climate Implications for Agricultural Nutrient Use Efficiency”. Adam Liska Papers. Paper 9.http://digitalcommons.unl.edu/bseliska/9

Richard Perry and Adam Liska, Researchers at the University of Nebraska , undertook an analysis of the global oil market, biofuels, population, climate change, and global agricultural production using current research to analyze the effect on agricultural methods.  Their research outlines the importance of increasing nutrient use efficiency for nitrogen fertilizers due to the number of huge external pressures placed on the current system.  After elaborating on each of the individual pressures, the researchers focus more closely on the need to increase energy outputs from biofuel production while making agricultural energy inputs more efficient to address the growing population and food security issues while maintaining low GHG emissions.  Because the inputs of land and energy are relatively fixed due to the diminishing availability of both, nutrients become the most elastic input and show the greatest potential for further research and improvement.
           The link between Nitrogen fertilizers and the global oil market best illustrates the influence of oil in modern agriculture.  The invention of the Haber-Bosch nitrogen fixing process has boosted crop yields to support an additional three billion people in the twentieth century alone.  Energy is needed in every step of fertilizer production, transport, and dispersal making it a ripe target for further research.  Improving the energy efficiency of the fertilizer process is hugely important because nitrogen fertilizers are vital to modern yield-boosting techniques.  The researchers found that nitrogen fertilizer represents 40% of the total energy input and creates 35.5% of the GHGs for the entire US corn production system.  Nitrogen fertilizers are mostly used in first world commercial agriculture, but once the necessary infrastructure for these methods is developed in the third world, global nitrogen use will increase dramatically.  Liska et al. noted that agricultural nitrogen is responsible for 10–12% of all human-related GHGs produced annually, with that number predicted to rise 35–60% by 2030 as nitrogen use increases in the third world.  These findings demonstrate not only how crucial cheap oil is to future food security, but also how improvements in nutrient use efficiency can dramatically reduce the costs of modern agriculture and alleviate pressure on declining oil resources.  Focusing on nitrogen containing fertilizers in particular would be the most effective way to increase national food and energy security while decreasing GHG emissions overall from an agricultural standpoint.
          To forecast the effects of increased biofuel use, the researchers performed an analysis of the relative efficiencies of the current US biofuels production system.  They found 90% of US ethanol mills, which produce biofuel from corn grain, run on natural gas, further spreading the energy burden away from crude.  The most recent surveys of corn-ethanol production show 1.6 energy units created per unit energy expended while emitting 47% fewer GHGs than gasoline.  Research into soy-ethanol has proved unpromising, while sorghum shows promise for further research into the lower bounds of nitrogen application having a low nitrogen uptake rate while maintaining a high energy yield.  Although corn continues to provide the main source of feedstock for biofuel production, if sweet sorghum can be grown with little to no fertilizer and compete with corn in terms of energy yield, it could greatly increase the lifecycle efficiency of biofuels overall.
          In assessing our best options to address the energy and nutritional needs of a booming world population, the researchers prefer to focus monetary and scientific investment on increasing the nutritional efficiency of nitrogen fertilizer because of its high oil inputs.  With the amount of arable land available already maximized, in order to boost future yields while still reducing GHGs in a warming world higher nutrient efficiency is essential.  Research into the reciprocal relationship between energy, agriculture, and climate change will continue, but for the present, the best way for the agricultural community to address all three issues lies with nitrogen fertilizers.

Addressing Public Views on GM Plants: How to Bioengineer Non-Pollinating GM Food Crops

With climate change and population growth predicted to place huge pressures on global food production and agriculture, ensuring crop yield growth in the future is of the utmost importance.  Scientific investment into non-technological and halfway solutions to this problem has been exhausted.  The advent of crop rotation, irrigation, and breeding boosted early civilization’s yields just as mechanized agriculture, artificial fertilizers, and new pesticides continued to improve our global productive capacity during the green revolution.  Looking to the future, Ryffel Gerhart of the European Molecular Biology Organization performed a survey of current research in order to formulate a strategy for changing negative public opinion on the next generation of yield-boosting technologies–genetically modified food crops.  Using the GM corn MON810, Gerhart posits a route to a more GM friendly future by stopping transgene crossing–the spreading of a GM gene into a traditional crop.  Gerhart sees the threat of cross-pollination between natural and GM plants as the biggest hurdle to widespread GM adoption in commercial agriculture.—Michael Gazeley-Romney
Ryffel, Gerhart U, 2011. “Dismay with GM maize”. EMBO reports advance online publication 9 September 2011; doi:10.1038/embor.2011.182.

Ryffel Gerhart, on behalf of the EMBO, researched alternative methods of developing genetically modified crop varieties with the aim of reducing public resistance to their widespread use.  He acknowledges that the “non-technological” and “halfway-technological” methods for increasing crop production have largely been exhausted and are now standard practice around the world.  Gerhart sees the most efficient expansion of future yields stemming from a high-tech solution like genetic modification.  In response to public suspicion of GM products, Gerhart utilizes MON810–a pest-resistant GM maize variety approved for commercial use in the EU–as a test case to first identify then repudiate the major public fears of genetically modified crops using current scientific research.  By describing how to create an apomictic, sterile maize variety that would eliminate the fear of cross-pollination, Gerhart’s research gives a feasible solution to increasing yield growth by creating social acceptance for a proven technology.  In the case of most genetically modified crops the evidence for their ability to boost production is proven, but their realized benefits are limited by social stigmas.
First, Gerhart addresses the concern of GM crop safety.  Gerhart cites a recent long-term study, finding no trace of the modified protein in milk or bovine plasma among livestock populations relying solely on MON810 as a feed source.  In response to the fear for human health, Gerhart draws from ten years of closely observed commercial use and long-term studies of the livestock consuming the crop to authoritatively state that there are no human or environmental health concerns related to MON810.  However in responding to public needs, packaging of GM foods should bear a marker in order to support consumer choice as well as monitor GM foods as their use grows.
With GM safety settled, Gerhart confronts the fear of GM outcrossing.  To acknowledge the realities of transgene outcrossing he cites several recent studies documenting outcrossing among maize populations in Mexico.  The Mexican study is significant because MON810 has not yet been approved for commercial use there yet and has still become a problem.  Another body of research from Guatemala thoroughly details the outcrossing there.  Whereas with human health, much of the public fear is essentially baseless, the potential for polluting nearby crops with GM genes is a real concern.  Gerhart uses a variety of studies to support the viability of his solution to the outcrossing problem.
According to Gerhart, genetic modification provides the solution to the outcrossing problem it creates.  As there is no realistic way of preventing pollen- and seed-mediated transgene outcrossing, the plant itself must be further modified to create a sterile seed-producing variety without the normal process of fertilization.  Referring to several papers on apoximis, a process through which seeds are produced by the plant absent fertilization, Gerhart demonstrates the viability of a GM-derived solution.  By deleting the pollen gene entirely, GM crops could be grown alongside native varieties without the risk of GM genes finding their way into the native populations.
With the stigma surrounding GM-based foods and the real danger of GM proliferation into traditional plant populations, promoting genetically modified crops as the answer to future food security is a tough sell by any means.  However, by increasing the availability of current research showing the safety of GM foods the stigma can be reversed.  Increased public support will encourage further scientific and monetary investment in GM technology which may someday make the outcrossing problem obsolete.  According to the European Molecular Biology Organization the door to our food-future has been opened, we must now gather the courage as a people to walk through it.

Rethinking Biofuels: Alternative Feedstocks Switchgrass and Miscanthus Predicted to Outperform Corn Grain Concerns over the potential effects of climate change on energy and food production in the last ten years have created a new market for alternative fuels. In the United States, corn-based ethanol, likely due to the political clout of the US corn lobby, has dominated biofuels research to date. However, corn may be ill-suited for ethanol production because oil is used in the production, transport, and application of the large amounts of nitrogen fertilizer necessary to boost corn yields. The nitrogen fertilizers have a detrimental effect on the environment by decreasing soil productivity and leaching into neighboring soils and water tables. With the advent of the US Energy Independence Act of 2007, the US government created demand for up to 15 billion gallons of corn derived ethanol per year, mandating any amount beyond that be produced from other feedstock sources. Although high in energy yield, corn’s dependence on oil makes it less efficient overall if environmental damage and GHG emissions are considered. The cap on corn ethanol production initially stimulated research into alternative feedstock, with preliminary research showing great promise from perennial grasses like switchgrass and miscanthus. The initial studies on the relative energy yield efficiency of corn and alternative feedstock prompted Parton et al. to develop a model capable of estimating the benefits of switching ethanol feedstock from corn to perennials. By using regression analysis of the DAYCENT model, they found that by substituting miscanthus and switchgrass for corn on lands already designated for ethanol production food productivity would increase by 4% and available feedstock for ethanol by 82% all while avoiding the GHG releases associated with the conversion of uncultivated land for agricultural production (known as ILUC, indirect land-use change).—Michael Gazeley-Romney Davis, S., Parton, W., Del Grosso, S., Keough, C., Marx, E., Adler, P., DeLucia, E., 2011. "Impact of second-generation biofuel agriculture on greenhouse-gas emissions in the corn-growing regions of the US". Frontiers in Ecology and the Environment; doi:10.1890/110003 Davis et al. simulated the effects of substituting 30% of the central US regional corn crop with three alternative biofuel crops: (1) switchgrass, (2) switchgrass with fertilizer treatments, and (3) miscanthus. Using the model they were able to calculate the feedstock production potential in each case as well as related GHG emissions, soil carbon sequestration, and nitrogen leaching over a ten year period. Their model is version of the CENTURY model that operates on a daily time step simulating exchanges between soil, plants, and the atmosphere as well as the affects of management practices like prescribed burning, grazing, and fertilizer use. To verify the accuracy of the model, the simulations were compared to test results from biofuel feedstock test plots already present in the study region finding close correlations for crop yields, GHG emissions, and nitrogen leaching. Using a simulation of ethanol corn production as a baseline, the researchers were able to calculate the differences in outputs between the growth scenarios. Possible imperfections in the model stem from the unknown effects of ILUC on GHG emissions. Although it is generally understood that large amounts of GHGs are produced in the tilling of virgin soil for agriculture, the amounts are hard to predict and can vary greatly. In order to compensate for this, Davis et al. calculated the effects of converting 30% of central US corn acreage to ethanol production using ILUC accounting from the California Air Resources Board finding emissions of 4.7–5.3 Tg C. When computed with the model results, the ILUC emissions did not have a significant effect on the large net differences between emissions for corn and those for the perennials. This is significant because the ILUC calculations should not apply to the test scenarios as no new land is being converted; the crops are simply being rotated. Controversy over outcrossing and slow investment realization (three years needed to establish perennial grass crops) are also omitted from the model analysis. However, both switchgrass and miscanthus present a low outcrossing risk because switchgrass is native to the US and miscanthus is a sterile hybrid. The results of the modeling showed significant environmental benefits from switching to perennial cellulose feedstock. These findings are more significant because the model was constructed to only consider the conversion of land already being used in ethanol production. In this way, the environmental benefits realized by switching feedstock crops comes absent the usual concerns about ethanol land use competing with food production. By limiting the model to a 30% corn-to-perennial land-use switch, the researchers hoped to simulate the complete transition from corn to perennial feedstock in US ethanol production (30% of all corn grown in the US is used in ethanol production). By avoiding the effects of ILUC entirely and only substituting feedstock within the existing production capacity of 30%, the study reduces foreseeable land use pressure from ethanol production on the 8% of US corn grown for food. Modeling of soil organic carbon (SOC) showed increases under fertilized switchgrass and miscanthus cultivation of 27 and 173 Tg Ceq yr-1 respectively. Compared to corn, fertilized switchgrass increased SOC by 1.9% and miscanthus by 19%. The conversion from corn to perennial feedstock changed also altered the regional output of GHGs–in terms of the re-appropriated cropland–from 27 Tg Ceq yr–1 for corn to 17 Tg Ceq yr–1 for switchgrass, –0.05 Tg Ceq yr–1 for fertilized switchgrass, and –97 Tg Ceq yr–1 for miscanthus. While the switchgrass succeeded in reducing agricultural GHG emissions, the substitution of miscanthus effectively transformed the entire region into a massive carbon sink. Davis et al. attributed the reduction in GHG emissions to less fertilizer use and increased carbon sequestration in the perennial crops compared to corn. Davis et al. reinforce the magnitude of this finding by citing a recent study that shows the reduction in GHGs from ethanol use (in the place of fossil fuel) are wholly offset by the heavy application of nitrogen fertilizers on corn. Using other research to interpret the significance of the modeling results, Davis et al. found that switching to perennial grasses would reduce nitrogen use overall, resulting in 0.7–0.8 Tg N yr–1 less nitrogen leaching through the soil. With 52% of the nitrogen polluting the Gulf of Mexico stemming from US corn and soybean production, the savings on environmental mitigation measures in the Gulf alone would be significant. To further demonstrate the relative benefits of switching feedstock, the researchers calculated the CO2 emissions from harvests of the corn and grasses, with the grasses producing 74% less CO2 during the harvest cycle. In a second run, Davis et al. altered the model constraints to substitute the perennials for corn on only the least productive 30% of the ethanol corn grown in the region. In this model the differences in efficiencies between corn and the perennials were even more pronounced with miscanthus producing 82% more biomass for ethanol feedstock than the corn baseline scenario, the equivalent of about twelve billion gallons of ethanol. As we continue to wean ourselves from foreign oil, energy efficiency within national production systems will take on a higher priority for policy makers. Choosing a low N-input, high energy-output feedstock over traditional corn has been shown under comprehensive modeling by Davis et al. to be much more efficient. When considering biofuels, it cannot be forgotten that they are meant to be a low-impact replacement for fossil fuels. With its dependence on oil for growth in the current agricultural system, corn has become an unsuitable and highly inefficient ethanol feedstock compared to perennial grasses. The findings of the study with regard to the yield efficiency and environmental benefits of miscanthus make it the clear choice for future feedstock use. In light of the findings of Davis et al., national production capacity for cellulose feedstock like miscanthus needs to be addressed in order to realize its benefits. Replacing corn ethanol feedstock in the central US region could increase the regional productivity of food by 4% and feedstock biomass 82% all while avoiding additional ILUC, making ethanol a truly environmentally friendly substitute to fossil fuel.

The population of the Sub-Saharan region increased by 670 million between 1990 and 2005.  According to the latest global population projections published by the United Nations in 2007, 80% of the world’s population growth will be concentrated in developing countries where pressures on food production due to climate change are also predicted to be highly intensified.  Due to the joint intensifications of climate change and population growth expected in these regions, studies of agricultural mitigation and its efficacy in boosting crop yields are now vital to future policy decisions.  Population and climate changes will increase food requirements and make growing those foodstuffs even more difficult.  With the Sub-Saharan population predicted to grow to between 1.5 and 2 billion between now and 2050, agricultural responses to climate change must begin now to maintain future food security in the region. Di Falco et al. analyzed geographic climate and yield data in a simultaneous equations model with endogenous switching to account for unobservable factors or skills that effect food productivity and individual farmers’ decisions to adapt their techniques to changing climate.—Michael Gazeley-Romney
Di Falco, S., Varonesi, M., Yesuf, M., 2011. Does Adaptation to Climate Change Provide Food Security? A Micro-Perspective from Ethiopia. American Journal of Agricultural Economics. 93, 829—846.

          Di Falco et al. elected to use a pre-existingan Ethiopian database of climate values and crop yields of the five major annual crops (teff, maize, wheat, barley, and beans) in considering the future food security of the region.  Ethiopia, having less than 60% of observed farms employing irrigation, 95% of the national yield being produced on family farms, and 75% of that yield being consumed at the household level typifies the poor, rain-fed regions where production in rain-fed agriculture is predicted to fall 50% by 2020 according to a 2007 IPCC report.  This makes it an ideal sample population.  The team analyzed seasonally disaggregated climatic data at the individual farm level through a simultaneous equations model with endogenous switching using the thin plate spline method of spatial interpolation, inputting household specific rainfall and temperature data at the correct geographic coordinates.
An important distinction in this analysis is the use of real and predicted food production instead of land value in analyzing the economic effects of climate change.  Di Falco et al. insist that due to the high primary consumption of food crops and inconsistent property rights in the developing world, crop production is more readily linked to living conditions than to land value.  Subsistence farming exists somewhat separate from the market system, making land market analysis an unreliable indicator of well-being in the at risk regions.
          In the first phase of the analysis, the researchers surveyed 1000 households in 20 districts, sampling data from 50 farm units within each district.  In surveying the farmers, Di Falco et al. discovered a direct correlation between the availability of information on climate change, access to credit, and the decision to adopt climate-adaptive farming techniques.  Most respondents perceived rising temperature and falling annual precipitation, but 40—50% of households because of lack of concrete information failed to act on their perceptions of climate change.  The importance of education programs in the form of farmer-to-farmer education and government extension is clear; especially in the developing world where literacy and access to current climate research are low, education is the most important factor in the ability of the population to adapt.
          In the second phase of analysis, the team analyzed the effects on food production of the adoption of agricultural adaptation techniques including changing crop varieties, adoption of soil and water conservation strategies, and tree planting.  There was a statistically significant correlation between rainfall and food production only in the households that did not adapt—leading the researchers to conclude that adaptation techniques made farms less susceptible to the extreme weather conditions that make food-production in the Sub-Saharan region difficult in the first place.  Crop rotation, which might be a good adaptation strategy elsewhere is ineffective in Ethiopia because crops are already highly diversified.
          In comparing the expected food productivity of the four test conditions (households that did adapt, households that did not, and the production values for those conditions if the opposite had been true; i.e. the households that did not, had adapted) within the endogenous switching regression model Di Falco et al. concluded that adapted households grew more food than non-adapted ones, and that taking adaptive measures eliminated this discrepancy. 
          The analysis of Di Falco et al. suggests that future policy objectives should be to concentrate on farms that have not yet embraced climate-linked adaptation techniques.  The team points out the obvious need for further research to differentiate the most effective methods of adaptation, but the results demonstrate the importance in raising the productivity in the bottom 1% performers in raising national food-production, weather-proofing yield estimates, and increasing food security in the region.

Future Global Maize And Wheat Yields Negatively Affected By Climate-Warming Trends; Soy And Rice Yields Relatively Unaffected

Concerns about the stability of agricultural yields under the influence of warming climates cannot be addressed by policy-makers at the national level without information on likely future trends. With rising food prices and an expanding population, the strain on the global food supply is predicted to rise precipitously under the additional influence of global warming and its endemic temperature and precipitation changes. In an effort to identify the likely future effects of global warming on agricultural production, Lobell et al. (2011) utilized publicly available data in order to predict the likelihood and magnitude of changes in global agricultural yields due to climate change. By extrapolating data on yields and weather trends between 1980 and 2008, the team concluded that wheat and maize will experience lower yields much sooner than rice and soy, and that climate change is already decreasing yields globally for these grains.–Michael Gazeley-Romney
Lobell DB, Schlenker W, Costa-Roberts J. 2011. Climate trends and global crop production since 1980. Science 333: 616-620.

Lobell et al. compiled publicly available data on crop production, location, yields, growing season, monthly temperature (T) and precipitation (P) for past warming events and trends between 1980-2008 in order to extrapolate the magnitude of climate change’s effect on future global agricultural yields. Since maize (corn), wheat, rice, and soybeans represent roughly 75% of calories consumed by humans globally, the team identified the data sets for these four crops as having a greater share of global agricultural production and nutritional needs. The yield models were computed graphically on a world map to better illustrate national and regional trends. The researchers normalized temperature variations by applying the historical standard deviation of year-to-year fluctuations in temperature. Countries underwent warming trends of at least one standard deviation in growing regions for rice and maize 65% globally while 75% of rice and 53% of soybean regions experienced the same warming (except for the U.S. which experienced a cooling during the same period, and grows 40% of the net global maize and soy supply) while a quarter of countries experienced a shift of two standard deviations.
The authors used a regression model to infer relationships between the crops, climate change, and actual climate in the regions affected. For example, a 1°C° increase in temperature tended to lower yields by 10% except in high latitude countries, where warming is actually shown to increase rice gains. Results on the effect of precipitation were closely grouped across all four crops and all regions, except in time-specific instances of heavy rains where flooding greatly reduced the viability of the crop.
The authors took rising CO2 trends into account using data from an earlier study to adjust the effect of a changing atmosphere due to warming on the different crops.  The prior study had found that rising CO2 trends would likely raise production of C3 plant varieties like rice wheat and soybeans by 3%.  The yield models predicted global yield decrease of 3.8% for maize, 2.5% for wheat, but a 2.9% increase for rice, and 1.3% increase for soy. By dividing the climate induced yield change by the overall yield change the team posited that a decade of climate change would reverse the positive yield-growth effect of a year of technological advancements. Armed with a comparative measure of the yield impacts of climate change, the research team found maize and wheat to likely be exacting a heavy toll economically on a global scale due to their nutritional importance and regional susceptibility to temperature change.  By identifying the danger to the availability of two major food crops due to climate change, policymakers will be able to more accurately create contingencies to alleviate future pressure on the largest portion of global foodstuffs.