Biophysical Potential

Past, current, and future soil and biomass carbon (C) dynamics under various management practices for the Old Peanut Basin are discussed in Tschakert (2004a) and Tschakert et al. (2004). Current soil C values were measured in the field and amounted to 11.3 metric tons ha-1 on average for the upper 0 to 20 cm soil layer. The average C stock in the 20 to 40 cm layer was 6.9 metric tons ha-1, with a mean soil bulk density of 1.6 g cm-3. Nowadays, such a low range is common for the area (Rabot,...

Carbon Sequestration by Smallholder Farming Communities

Most carbon offset projects involve a large carbon emitter in an industrialized nation contracting with a tropical government to protect a large area of primary forest from deforestation, thereby avoiding the emission of more carbon. This process excludes many farmers from the process. Given the large emissions due to tropical deforestation, shown in Table 1.2, such protection is very important. But this does not result in substantial carbon reductions in the atmosphere, since primary forests...

Introduction

The possibility of using improved farming practices to mitigate the increase in atmospheric CO2 through soil carbon sequestration (SCS) reached international consensus during meetings leading to the Intergovernmental Panel on Climage Change (IPCC) First Assessment Report (1990). The rationale for this consensus was that by fostering the adoption of improved farming practices, it would be possible not only to enhance agricultural productivity but also to make soils act as sinks for atmospheric...

Preface

Anthropogenic perturbation of the global carbon cycle has increased the atmospheric concentration of carbon dioxide, and decreased the carbon pool in the world's agricultural soils. Since the industrial revolution, the atmospheric concentration of carbon dioxide has increased by about 30 from 280 parts per million by volume (ppmv) to 370 ppmv. This increase is attributed to emissions of carbon from fossil fuel combustion estimated at 270 Pg (gigatons), and from land use change and soil...

References

The effect of organic matter on the bulk and true densities of some uncultivated podzolic soils. J. Soil Sci., 24 10-17. Baldocchi, D.D. and K.B. Wilson. 2001. Modeling CO2 and water vapor exchange of a temperate broadleaved forest across hourly to decadal time scales. Ecol. Modeling, 142 155-184. Ben-Dor, E. and A. Banin. 1994. Visible and near-infrared (0.4-1.1 jam) analysis of arid and semiarid soils. Remote Sensing Environ., 48 261-274. Bhatti, A.U., D.J. Mulla, and B.E....

Results

Results obtained on two hillsides with a 35 slope in the Mazateca region during the first 3 years, indicate that the average yield of maize varies widely between treatments. It ranged from 0.63 to 6.62 Mt ha-1, as reported in Table 23.1. Yields for the traditional slash-and-burn system were ten times lower than those for milpas intercropped between rows of peach trees with a spacing of 1.0 m in the rows, and using poultry waste manure for the maize along with mineral fertilizers. Yields for...

Overall Findings from Case Studies

The scenarios show that CS in tropical dryland soils can be achieved at the various sites (Table 21.2). The land management practices were chosen to be in accordance with the current farming systems and provide specific real cases for CS strategies in different dryland systems. For example, application rates of organic matter are commensurate with quantities that should be available to local farmers. However, at the field level, important tradeoffs may occur, preventing adoption of the best...

Sequestering Soil Carbon

There is worldwide interest in the sequestration of soil C to reduce the amount of C going into the atmosphere as carbon dioxide. An estimated 40 to 50 Pg of carbon (Pg C 1 petagram carbon 1 billion metric tons of carbon) have been released from the soil worldwide (Lal et al., 1997). Most of this loss has resulted from the conversion of forest and grassland ecosystems into agro-ecosystems for the production of food and fiber. Crop production requires relatively large amounts of N, P, S, and...

State of Agriculture

Agricultural production in the latter half of the 20th century increased, with the global food supply outstripping the increase in global demand for food this was accomplished in spite of increases in global population and incomes. As a result, prices for most major crops declined when adjusted for inflation. Wheat and feed corn declined at an annual average rate of 1 to 3 over the period (Johnson, 1999 Antle et al., 1999). In the absence of climate change, several analysts (e.g., World Bank,...

Terrestrial Carbon Sequestration and Food Security

Carbon sequestration in soil and vegetation, as well as temporal and spatial variations in relation to land use and management and their related policy issues have major implications for global food security, climate change, and environmental quality. 30.1.3.1 Environmental and Socioeconomic Context for Soil Carbon Sequestration Land degradation is a constant major threat to food security, especially in Africa and Asia. Soil carbon sequestration (SCS) can be a major way to counter increases in...

Contents

1.1 Reducing Hunger in 1.2 Coping with Climate 1.2.1 1.3 Estimating Biomass of Young Tropical Vegetation 8 1.4 How to Measure Soil 1.5 Sharpening Predictive Tools for Key 1.6 Adapting to Thermal 1.7.1 High Carbon Sequestration Potential of Tropical 1.7.2 Carbon Sequestration by Smallholder Farming 16 Most of the world has witnessed dramatic increases in per capita food production over the last 30 years. However, the opposite occurred in Sub-Saharan Africa. Per capita food production in this...

Limited Use of New Technologies

The only option to sustain production growth is to increase yields. Within the developing world, average regional grain yields are the highest in North Africa, and the lowest in Sub-Saharan Africa. Yields are highly dependent on the use of additives, particularly fertilizers. The principal factor limiting yield response to fertilizer use is the inadequate supply of water during the growing season. Although water availability varies considerably across regions, it has been a serious problem in...

Agroforestry on Soil Organic Carbon

The three major land use categories in Zambia are cropland, forest reserves, and national parks. Forest reserves and national parks cover about 10 and 8 of the country, respectively, and are managed by the Forest Department and the National Parks and Wildlife Services (German Technical Cooperation GTZ , 1995). Forests in Zambia are used for agriculture, wood fuel, and timber harvesting. Out of 753,000 km2 total land area, about 420,174 km2 or 56 of the land area is potentially available for...

Future Perspectives

There is another part of the equation relating food production and population growth that remains a puzzle how much food, and how varied a diet, is required for each member of the population This is not a topic on which I can claim any authority. Nevertheless, I feel that it merits attention in relation to future perspectives. There is now an extensive literature, provoked initially in regard to protein, following the large reductions in the FAO figures for essential quantities required,...

Historical And Future Climate And Co2 Concentration

Monthly historical climate data from 1930 to 1996, compiled and interpolated to a regular geographic grid by New et al. (2000), were obtained from data sets maintained by the National Aeronautics and Space Administration's Distributed Active Archive Center at Oak Ridge National Laboratory Projected future climate was generated by the coupled parallel climate model (PCM) (Washington and Weatherly, 1997). PCM model output for the stabilization scenario was obtained from the National Energy...

Modeling Database

Data from the subhumid agroclimatic zone (Lake Victoria crescent) were used to test the predictive performance of the model. The data set was compiled from 1998 to 2002, using runoff plots (15 x 10 m) established in four major agricultural land use types (annual crops, banana, coffee, and range lands), under the Lake Victoria Environmental Management Project (LVEMP). Each land use type was replicated three times, except banana, which was replicated four times. Plots under banana were mulched...

Past Perspectives

At least in the English-speaking world, most credit for drawing attention to the problems posed by potential food insecurity is given to the Reverend Thomas Robert Malthus, who lived from 1776 to 1834. He was preceded by many others, including Greeks, Romans, and Chinese (Evans, 1998) and Saether (1993) notes that there was a Dane, Otto Diederich Lutken, who wrote on the same theme 40 years earlier than Malthus. The Greeks, like Malthus, were mostly philosophical in their approach, whereas the...

Global Food Security

Soil C sequestration can be made a win-win proposition. It is an important objective of both adaptive and mitigative strategies to minimize or reverse the effects of global climate change, although they approach this aim differently. The adaptive strategy by increasing the SOC pool would enhance soil microbial activity and would accentuate soil physical, chemical, and biological quality. Soil quality improvements could negate some or most of the adverse effects of climate change on crop growth...

Carbon Transported via Sediments

Although differences and trends in sediment transport can be noted based on tillage practice or crop year (Table 18.3), the year-to-year variation was so great that there were not significant differences among the values reported. The standard deviation was almost always greater than the mean for each practice and year. This was also true for the transport of C in the sediments. The lowest annual sediment transport occurred with no till and the highest with disk. With the exception of the...

Summary And Conclusions

Many people in low-income countries are food insecure. Research suggests that rising concentrations of greenhouse gases are likely to affect food security even more in the future. Some effects of greenhouse gases, such as CO2 fertilization, are likely to increase food security, while others, such as rising sea level, are likely to reduce food security. Of particular concern, however, are the potentially damaging effects of rising temperatures associated with global climate change. Countries in...

Conclusions

The present status of policies for carbon sequestration and how they relate to agricultural sequestration was reviewed in the first part of this chapter. The current mix of local, national, and international policies does not create any well-defined global cap on acceptable emissions, and therefore it does not provide the basis for a well-functioning market for GHG emissions reductions credits. A market price for carbon that reflects the social opportunity cost of reducing emissions will exist...

Competition and Abiotic Conditions

Much remains to be learned about responses by pest insect populations to anticipated climate shifts (Lawton, 1995 Lindroth, 1996b Davis et al., 1998 Harrington et al., 1999). Insect pest populations can rapidly and unexpectedly build to large numbers in response to environmental changes, including changes in weather (Cappuccino and Price, 1995 Dempster and McLean, 1998), resulting in significant plant damage (Hewitt and Onsager, 1983 Barbosa and Schultz, 1987). Potential impacts of climate...

Century Ecosystem Model

Century is a model of SOM and nutrient dynamics that emphasizes the decomposition of SOM, and the flux of C and N within and between different components (Parton et al., 1987). The grassland crop and forest systems have various plant production submodels that are linked to a common SOM and nutrient cycling submodel (Figure 9.2) that has been fully described before (Metherell et al., 1993 Parton et al., 1994 Paustian et al., 1997 Kirschbaum and Paul, 2002). In brief, the model includes two...

Sensitivity Of Tropical Agriculture To Climatic Change

The tropics is a geographic region, defined by 23.5 degrees north and 23.5 degrees south latitude (Agnew, 1998). The tropics are home to some of the world's poorest populations. Although considerable variability exists within the tropics, their climates are generally distinguished by the persistence of high year-round temperatures and the convective and highly seasonal nature of rainfall. And, although precipitation is one of the more difficult variables to simulate accurately in climate...

Coping With Climate Change

The Third Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) stated for the first time that scientific evidence of human-induced global warming is unequivocal, and that the latest predictions are much worse than previous estimates (Houghton et al., 2001). The last 100 years have been the warmest on record. Furthermore, warming during the last 50 years has a clear human signature. Global temperatures will increase by 1.4 C to 5.8 C by 2100 sea levels are rising and are...

Climate Change and Food Security Projections for 2012

The food distribution gaps projected for 2012 (Section 4.2.2.2) implicitly include the effects of climate change because they were based in part on historical trends. The long-term impacts of climate were isolated from other factors by estimating total percent changes in growing season for the 2002-2012 period, quantifying the relationship between growing season lengths and crop yields, removing the climate-induced changes in yield from the base yield projections, and re-estimating the food...

Livestock Demand The Global Wealth Effect

Higher incomes and urbanization are leading to major changes in dietary patterns. A massive increase is foreseen in per capita consumption of fish, meat, and milk products, especially in populous and increasingly prosperous Asia (Delgado et al, 1999). Expanding poultry and livestock demand, in turn, will result in major increases in the share of cereal production consumed by livestock, a trend which runs the risk of reducing cereal availability for the very poor and food insecure in coming...

General Findings On Climate Change Impact

Across the large number of climate change-related studies several key findings have emerged regarding physiological effects on crops and, to a lesser extent, livestock. Following McCarl et al. (2003), the main findings are Table 29.1 Ranges of Estimated Effects on Country Crop Yields Pakistan Sri Lanka Bangladesh Mongolia Kazakhstan Czech Republic United Kingdom The Gambia Rice -2.5 and +5.4 soybeans -2.3 maize -40 Rice -22 to -12 maize no change rubber -30 to -3 Wheat -60 to -10 Rice -2.1 to...

Adaptation

Farmers have always had to adapt to the vagaries of weather, whether on weekly, seasonal, or annual timescales. They will undoubtedly continue to adapt to the changing climate in the coming decades, applying a variety of agronomic techniques, such as adjusting the timing of planting and harvesting operations, substituting cultivars, and ultimately changing the entire cropping system. However, it is important to remember that farming systems have never been completely adapted even to the current...

High Carbon Sequestration Potential of Tropical Agroecosystems

A recent IPCC study on land use, land-use change, and forestry (Watson et al., 2000) documented the large potential for tropical agroecosystems to sequester carbon. The tropics have two major advantages over the temperate regions. Trees grow faster under high year-round temperatures and high solar radiation. In addition, many tropical soils are depleted of carbon because of unsustainable land use practices. Table 1.2 illustrates the potential for carbon sequestration in the tropics. Land use...

Acknowledgments

Gridded monthly weather data were supplied by the Climate Impacts LINK Project (United Kingdom Department of the Environment, contract EPG 1 1 16) on behalf of the Climate Research Unit, University of East Anglia. We would also like to thank Todd P. Mitchell of the University of Washington for help in obtaining and understanding the Cold Tongue Index, and directing us to the Southern Oscillation Index. We are also grateful to John Sullivan, Kevin Ingram, and three anonymous reviewers for their...

Carbon Loss In Subsurface Flow

Seven monolith lysimeters, each having a surface area of 8.1 m2 and a depth of 2.4 m, were used to study TOC moving through the soil profile under a corn soybean-rye rotation Table 18.3 Average Annual Wheel and Total (Wheel Plus Flume Floor) Sediment and C Transport by Crop and Tillage Practice Wheel Sediment (kg ha) Total Sediment (kg ha) Table 18.3 Average Annual Wheel and Total (Wheel Plus Flume Floor) Sediment and C Transport by Crop and Tillage Practice Wheel Sediment (kg ha) Total...

Agriculture Organization And Climate Change

Issues related to climate change are high on the agenda of the Food and Agriculture Organization of the United Nations (FAO). FAO is an active partner in the implementation of the different conventions related to climate change, notably UN Framework Convention on Climate Change (UN-FCCC ), UN Convention to Combat Desertification (UN-CCD), and the Convention on Biological Diversity (UNCBD). FAO is particularly concerned with the effects of agricultural (including forestry and fisheries)...

Goals Of Impact Studies

Many of the climate change studies done to date, particularly the early ones, were undertaken to aid national policymakers to assess the significance of global climate change and its implications for broad regions as well as for whole countries. These studies are thus policy relevant in the sense that they may contribute to national decisions on whether and how to participate in the U.N. Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol. Questions here revolve around how...

The Standard Model

A seminal development in economics since World War II is validation of the standard model for economic progress. The model has been presented elsewhere (Tweeten et al., 1992 Tweeten and McClelland, 1997 Tweeten, 1999), and is outlined only briefly in this section. Any country following the standard model can be assured of sufficient national product to be food secure. Of course, economic progress differs among countries adopting the standard model because countries differ in natural endowments...

Agriculture Regions Will Experience Change over Time

Due to all the agro-ecosystem processes described above, it is fairly certain that agricultural regions will experience some changes, and that these changes will evolve continuously through the coming decades. Shifts in crop zonation are likely to occur, with some crop types expanding their ranges and others contracting. Given the range of projected temperature and precipitation changes from global climate models, and the unknown degree of manifestation of direct CO2 effects on crops growing in...

In The Near Future

The remainder of this chapter focuses on the extent to which global climate change may contribute to food insecurity in the relatively near term, or 2012. The emission of greenhouse gases has already been associated with a rise in mean global temperature of from 0.3 C to 0.6 C since the late 19th century (Intergovernmental Panel on Climate Change, 2001). This has been accompanied by changes in precipitation in some locations as well. Several major impacts of such climate changes on food...

Modeling Components

Global climate models represent the only tool available to assess future impacts of changes in global radiative forcing (e.g., increasing greenhouse gas concentrations, presence of sulfate aerosols, and changing land-use characteristics) on climate. Global climate models all project the global mean temperature of the planet to increase over the next 100 years, but at different rates depending on the model. Approximations used in climate models and lack of fine-scale resolution are sources of...

Section V Policy and Economic Issues

Policy and Economic Issues Dealing with Global Warming 641 Confronting the Twin Problems of Global Warming and Food Policies and Incentive Mechanisms for the Permanent Adoption of Agricultural Carbon Sequestration Practices in Industrialized and Developing 679 The Impact of Climate Change in a Developing Country A Case Study from

Food Web Tritrophic Interactions

What are the consequences of food web dynamics and trophic cascades for crop production and food security For the most part, empirical research indicates that insect herbivore populations are regulated by both natural enemies (top-down effects) and food resources (bottom-up effects). Moreover, natural enemies of herbivores are not top predators in most agro-ecosystems, and they typically are attacked by another tier of pathogens, parasites and predators. While the above examples emphasize...

Setting

At the beginning of the 21st century, some 30 of the world's population suffered from one or more forms of undernutrition (FAO, 2002). Approximately 800 million persons remain undernourished, facing daily shortfalls of 100 to 400 kilocal-ories in meeting basic energy requirements. Micronutrient deficiencies are even more widespread, with an estimated 2 billion people afflicted by anemia mainly from iron deficiency, thus causing mental retardation and other disorders. Some 740 million people...

Reducing Hunger In Africa

The time is right to drastically increase the productivity of African agriculture and to improve human nutrition, with a new and highly focused action plan, called the Doubly Green Revolution in Africa. Doubly green means increasing productivity in environmentally sustainable ways (Conway, 1997). In response to a request from the UN Secretary General in February 2003, the U.N. Millennium Project's Task Force on Hunger is developing a plan to attain the Millennium Development Goal of cutting...

Identification Of Researchable Priorities

Researchable priorities are region-specific, and they are defined in great measure by physiographic, soil, climate, socio-cultural, economic, and political factors. Several major criteria that can be used to identify key researchable priorities are discussed below. Probable impacts of climate change on food production. What is the current status of food supply and demand for individual nations and for the world, and how might it change because of climate changes Current information suggests...

Region

This region covers major valleys of Zambia such as Gwembe, Lunsemfwa, and Luangwa, and the southern parts of Western and Southern provinces. Mean annual rainfall in Region 1 is low, up to 800 mm, and is generally well distributed. It is the driest and most drought-prone region. Temperatures in the growing season are generally high, and range from 20 C to 38 C. The soil groups are either clay soils with fine loam topsoil and slightly acid, or alkaline with minor fertility limitations and good...

Agricultural Production in Many Developing Countries Is Especially Vulnerable

Despite general uncertainties about the rate and magnitude of climate change and about consequent hydrological changes, regional and global studies have consistently shown that Table 10.1 Effects of Climate Change on Global Food Production Under Various Scenarios (Percent Change in Yield) Table 10.1 Effects of Climate Change on Global Food Production Under Various Scenarios (Percent Change in Yield) agricultural production systems in the mid and high latitudes are more likely to benefit in the...

Climate And Agriculture

Climate is the single most important determinant of agricultural productivity, primarily through its effects on temperature and water regimes (Oram, 1989). For example, the physiographic boundaries of principal biomes are determined by mean annual temperature (Mooney et al., 1993) and soil water regimes. Climate change is therefore expected to alter the biophysical environment of growing crops and to influence biomass productivity and agronomic yields (Rosenzweig and Hillel, 1998). Positive...

Hunger Still Stalks Asia

Despite the ability of smallholder Asian farmers to triple cereal production since 1961, the battle to ensure food security for millions of miserably poor people is far from won. Huge stocks of grain have accumulated in India, while tens of millions need more food but do not have the purchasing power to buy it. China has been more successful in achieving broad-based economic growth and poverty reduction than India. Nobel Economics Laureate, Amartya Sen (2000), attributes China's achievement to...

Materials And Methods

Uganda (30 E1 S, 35 E4 N) is located in East Africa (Figure 20.1). It is characterized by diverse agricultural systems that have evolved from the interaction of several factors governing land use (climate, soil, terrain, and socioeconomic factors) (Komutunga and Musiitwa, 2001). In Uganda, the climate varies with altitude, which ranges from 610 m in the rift valley to 4324 m on Mount Elgon. Mean annual rainfall ranges from 510 mm in the semi-arid northeast of the country to 2160 mm in the Ssese...

The Broader Policy Perspective

Implementation of the Kyoto Treaty should take place within the context of a broader perspective on the evolution of international policy institutions. Rapid and significant initiatives are taking place in this broader context. Globalization, for example, is causing economic policymaking and implementation to be increasingly beyond the reach of national economic policymakers. The loss of national sovereignty over economic policy is the source of much contemporary concern in this country, as it...

Farmer Participation in Carbon Contracts

We now consider the farmer's decision to participate in carbon contracts in a heterogeneous region, following Antle and Dia-gana (2003). They show that, if expected net returns and the price of carbon are constant over time and the fixed cost of changing practices is equal to zero, the farmer formerly using practice i will adopt the carbon-sequestering practice s if NR(p, w, z, s) + g(i,s) - m(i,s) - fc(i,s) > NR(p, w, z, i) where NR(p, w, z, j) is the net return to practice j i,s p and w are...

Conceptual Basis For Carbon Sequestration In Soils

The nonliving organic matter in soils is generally considered to be in three pools (1) a labile pool that is free within the soil matrix, (2) a physically protected pool that is within larger aggregates, and (3) a chemically protected or mineral-associated pool that is within the smallest aggregates (e.g., Paustian et al., 1997 Jenkinson and Rayner, 1977). The specific aggregate sizes associated with these pools vary with soil type, but chemically protected organic matter can be considered to...

Example Results

Jones et al. (2004) presented a sensitivity analysis to assess the benefits of using this EnKF to estimate SOC over time, relative to measurements alone, for different combinations of model parameters, errors, and initial conditions. Here, base case results from this study are summarized, and it is shown how errors of SOC estimation vary over time under different frequencies of measurements (and thus, frequencies of updating estimates of X and R). To demonstrate numerical values, realistic...

The Potential For Disciplinary Synergism

This volume provides an example of the potential synergism from interdisciplinary collaboration in research on global warming. Given the degree of disciplinary specialization that prevails in academic circles, it is difficult to realize the synergism that comes from cooperation. The most difficult cooperation tends to be that between the biological and natural sciences on one side, and the social sciences on the other. It is across these boundaries that the communication problems are greatest,...

Temperature

Determining climate information for assessing future crop growth, by whatever methods, requires more than monthly mean values of temperature and precipitation. For a changing or variable climate, higher-order statistics, such as variance, extremes, and persistence, may have more significant influences than changes in the mean (Takle and Mearns, 1995 Mearns et al., 1997). For example, a month having a run of several consecutive days of extreme high temperatures (higher autocorrelation of the...

Assessment Methodology

Four principal steps were used to complete the analysis. First, the climate change projections from HadCM and CGCM were superimposed on the data from 72 weather stations across Mali. Second, the biophysical models were run with the CO2 level set at 1.5 times the current level of 330 ppmv (parts per million by volume). The mean and standard deviation of yields across 85 agroecological zones in Mali were computed and weighted into sensitivity data for nine MASM production zones. (Information...

Soil Organic Carbon Sequestration Strategy

Several practices and strategies that have been recommended to improve soil fertility for farming systems in Zambia also enhance SOC. These strategies and practices include 1. Returning organic materials to the soil to replenish SOM lost through decomposition 2. Ensuring minimum disturbance of the soil surface 3. Reducing soil temperature and water evaporation through mulching with plant residues 4. Integrating planting of multipurpose trees and perennials 5. Improving fallows to increase...

Models

SOM models or agroecosystem models with specific treatment of SOC dynamics represent our conceptual and quantitative understanding of the mechanisms regulating C transformations in soil. Well-tested models have successfully been used to simulate SOC changes at various temporal (day to century) and spatial (site to national) scales. When well-initialized and calibrated (if necessary), simulation models have been capable of describing historical trends in SOM dynamics observed in long-term...

Soil Moisture

Soil moisture values for the 1981-1988 period simulated by RegCM2 were compared with observations of soil moisture for the state of Illinois as reported by Hollinger and Isard (1994) and Robock et al. (2000). Composite monthly mean values for the 8-year period (Figure 15.5) for the top 10-cm layer show a winter-spring recharge of soil moisture and a growing-season drawdown. Simulation of the deep soil (figure not shown) reveals a persistent dry bias in the model, whereas the simulation of the...

Effects on Agricultural Production Systems Will Be Heterogeneous

Global studies done to date show that negative and positive effects will occur both within countries and across the world. In large countries such as the United States, Russia, Brazil, and Australia, agricultural regions will likely be affected quite differently (Figure 10.4). Some regions will experience increases in production and some declines (e.g., Reilly et al., 2003). At the international level, this implies possible shifts in comparative advantage for export crop production. This also...

The Kyoto Treaty as a Starting Point

The United States has a great deal to offer to global society by rejoining the efforts to implement the Kyoto Treaty, and by recommitting to the objectives of that treaty. The United States has substantial scientific, technological, and analytical capability needed to address these issues. We could use these resources to help identify the optimal acceptable degree of global warming. Such a concept should guide the Kyoto Treaty initiative. However, we also might scale down the scope of this...

Conclusion

Cutting hunger and malnutrition in half in Africa is a perfectly feasible goal in the next 10 years, if the world community decides to do it, and if it can address major climate change threats such as thermal damage. The international community has successfully tackled hunger before, when widespread famine was averted in Asia. It can do it again in Africa. Hunger has been defeated twice in the last 50 years the Marshall Plan after World War II and the Green Revolution during the 1960s through...

Climate Change

Climate change projections are fraught with much uncertainty in regard to both the rate and magnitude of temperature and precipitation alterations in the coming decades. This uncertainty derives from a lack of precise knowledge of how climate system processes will change and of how population growth, economic and technological development, and land use will proceed in the coming century (Intergovernmental Panel on Climate Change IPCC , 2000, 2001). Nevertheless, three points regarding climate...

Food Security And Greenhouse Gases

Rising atmospheric concentrations of greenhouse gases are expected to affect food security through their impacts, both positive and negative, on agricultural productivity (FAO, 2003a). Impacts are generated through four mechanisms CO2 fertilization, climate change, extreme weather events, and rising sea level. Agricultural production, a requirement for food security, also emits greenhouse gases. Emissions associated with land-use change and land degradation are particularly important in...

Concluding Comments

Two points should be made in conclusion. First, at the start of this chapter, I argued for trying to identify an optimal temperature for the Earth, or the optimal degree of global warming, but the following discussion dealt with how we might more effectively address the problem of global warming. While I believe that our efforts at dealing with global warming would be more persuasive and effective if we knew more about our objective function the most desirable position to occupy that is no...

Climate Change and Net Primary Production

Three globally significant issues are as follows 30.1.1.1 Climate Change CO2 Fertilization Impacts on Terrestrial Ecosystem Production The relative contributions of CO2 fertilization and climate change effects on terrestrial CO2 sources and sinks have been estimated for different ecoregions. They suggest that the CO2 effect on total net primary production (NPP) content will be positive, and that NPP will decrease without it. On the other hand, the effect of projected climate changes on total...

Opportunities For Carbon Sequestration In Soils

The conceptual model presented in Figure 17.1 illustrates that carbon sequestration potential is related to soil texture and the intensity of tillage. The greatest potential for carbon sequestration is with fine-textured soils that have been carbon degraded due to intensive tillage. Many such soils exist in developed countries, where large tillage equipment is the norm. In tropical environments of the developing world, soils that are in a paddy rice-upland crop rotation are the most carbon...

Mitigation Options in Zambian Forest Sector

Mitigation options to reduce soil C loss consist of maintaining existing stocks and expanding C sinks as described below. 25.3.4.1 Maintaining Existing Stocks Forest protection and conservation, and increased efficiency in forest management, and in harvesting and utilization of forest products are the main ways to maintain existing stocks. Measures in this category aim to increase biomass stocks so as to reduce the current deficit. These measures are expected to increase forest land area (or...

An Optimal Degree Of Global Warming

Global warming issues are hard to resolve, in part because their discussion is so open-ended. Contemporary discussions have concentrated on ways to mitigate or reduce global warming, rather than looking beyond those objectives. In the prevailing estimates of the costs and benefits of global warming, there is an implicit assumption that there is some optimal degree of global warming, or some optimal temperature for the Earth, and that there is only one direction to move in attaining it to...

CoBenefits and Costs

Many soil conservation and other management practices that would increase soil organic carbon (SOC) were not developed and promoted to enhance the accumulation of soil carbon per se, but rather to increase agricultural productivity, reduce soil erosion, and reduce off-farm impacts of soil erosion on water quality. In regions with predominantly subsistence or semisubsistence agriculture, the various soil management practices that contribute to carbon sequestration also are likely to have...

Complexity Of Communitylevel Food Webs

It is reasonable to expect that climate change will affect the temporal and spatial associations between species interacting at different trophic levels (Porter, 1995 Sutherst et al., 1995 Harrington et al., 1999 Gutierrez, 2000 Walther et al., 2002). What happens to our predictions as we increase the number of species that must be included in our analyses Understanding the impact of climate changes on herbivore-predator interactions may be as or more important than plant-herbivore interactions...

Implications Of These C Loss Pathways For Management

An important aspect of relating management practices to carbon sequestration is quantifying the pathways of C loss from soil as well as measuring the increase in C storage and the net amount of C stored. The above review showed great variability in the amounts of sediment and C transported within a management treatment. Nevertheless, there was no Table 18.5 Flow-Weighted Averagea Monthly Total Organic Carbon Concentrations in Subsurface Flow Minimum Maximum Mean Standard Deviation Coefficient...

Adapting To Thermal Damage

The mean maximum temperature for much of the tropics where crops are grown is 34 C. The IPCC Third Assessment Report indicates that temperatures are going to increase throughout the tropics, regardless of changed rainfall regimes. J. Sheehy of the International Rice Research Institute (2003) has observed that the fertility of rice flowers falls from 100 at 34 C to near zero at 40 C, regardless of CO2 levels in the atmosphere (Figure 1.2). Any increase in temperature due to global climate change...

Strengthening the Knowledge Base

The lack of knowledge on important issues becomes obvious as one participates in debates surrounding global warming. A number of priorities quickly emerge. The first, and perhaps most fundamental and glaring, is the lack of a consensus among scientists on the underlying causes behind the observed changes in global temperatures. We know that historically these temperatures have experienced both short-term fluctuations and longer-term trends. Despite the substantial additions to our knowledge,...

Research Pathways

To better address the interactions between climate change and sustainability of food and fiber production, we suggest the following areas for future research attention. 10.7.1.1 Climate Variability and Change Another bifurcation in the field of climate impacts has occurred between research on responses to major systems of climate variability, such as between the El Ni o-Southern Oscillation and long-term global warming. The insights that have been gained from studies of agriculture in regard to...

Summary

A strategy is needed for translating changes and variability of global climate into impacts on agriculture. Global models, which are needed to evaluate global consequences of anthropogenic influences such as changes in greenhouse gas concentrations, do not supply climate information of sufficient resolution to meet this need. Regional climate modeling is conceptually more appealing than statistical downscaling, and captures some fine-scale dynamical processes that are unresolved by global...

Global Climate Models

Current global models project the global mean temperature to rise 2.5 C to 6 C, over the next 100 years with comparable or larger variation on regional scales. Changes in precipitation have large variation among models, with some indicating substantially lower mid-continental precipitation and others providing increases. Narrowing the range of uncertainty in determining impacts of climate change under such disagreement requires use of ensembles of global models to capture the uncertainty and to...

Intellectual Property Rights the Regulatory Process and Scientific Innovation

Much has been written and discussed about the way in which intellectual property rights legislation and patents has distorted research objectives, raised product prices, slowed the exchange of scientific findings and genetic materials, and otherwise negatively impacted research results reaching the consumer in a timely and economical manner. Each of these concerns has some validity. It is also true, however, that insuring exclusive control over or exploitation of for innovators and developers...

Carbon Concentration in Sediment

Surface runoff from the watersheds was automatically measured with H-flumes and sampled with Coshocton wheels (Brakensiek et al., 1979) that were modified to continuously deliver a proportional sample of runoff water and suspended sediment during each runoff event. Sediment was occasionally deposited in the flume floor and flume approach. This sediment was also collected. Sediment losses occurred almost every year from each of six small watersheds (Table 18.1) during the 15-year study period,...

Combining Measurements And Models For Estimating Soc Sequestration

If soil C sequestration is to become an accepted mechanism for reducing atmospheric CO2 levels, a soil carbon accounting system needs to be developed (Antle and Uehara, 2002). Mass of carbon accumulation in soils is of interest, so measurements will include field sampling, laboratory determination of carbon, and its conversion to mass basis using soil bulk density. Thus, errors in such measurements would include errors associated with each step. As a result, yearly changes in soil C are small...

Sequencing Development

The issue of which sector should lead economic growth of poor countries has been controversial since R. Nurske (1953) made a case for balanced growth among sectors and A. Hirshman (1958) rebutted the argument by making the countercase for unbalanced growth. The lesson of the standard model is that public policy must not be fragmented, but, realistically, not all elements of the standard model can be pursued simultaneously. The general rule is to allocate resources and achieve growth in services...

Agroecosystems

Most modeling to forecast climate change impacts on crop yields uses average weather data adjusted for forecasted national variations. Using average data ignores both the inherent variability of weather and its effect on crop yield, and hence food security, as the climate changes. A methodology has been developed and tested that allows outputs from global circulation models (GCMs) to be downscaled and applied to point simulation models (Jones and Thornton, 2001). It is possible to model and map...

Scenarios Used for Impact Assessment

To assess climate change effects under adaptation we set up five scenarios (1) base cropping patterns, (2) regional shifts in cropping patterns, (3) allow both crop pattern shift and trade adaptation, (4) introduce heat-resistant crop varieties, and (5) consider the effects of 1 though 4 simultaneously. We did not consider changes in planting and harvest dates, as the EPIC results did not show favorable adaptations from that source. In Mali, planting schedules are heavily dependent on when the...

Environmental Pressures On Agriculture

The degradation of environmental assets, especially soils, air, and water, severely challenges the productivity of agriculture and forest resources (Pinstrup-Andersen and Pandya-Lorch, 1998 Price et al., 1999a, 1999b). In the post-World War II period, approximately 23 of the world's agricultural and forest lands were classified as degraded by the U.N. Environment Programme (Oldeman et al., 1991). Irrigated land is particularly vulnerable, although the expansion of irrigation is slowing....

Combining Models And Data To Assess Options For Soil C Sequestration

Two of the biggest constraints for improving household food security in West Africa are retention of rainwater in the field and improvement of soil quality (Kaya, 2000 Lal, 1997a, 1997b Ringius, 2002 Bationo et al., 2003). The practice known as ridge tillage or am nagement en courbes de niveau (Gigou et al., 2000) was designed to address these issues concurrently, and is thought to have potential for sequestering SOC. This is logical since ridge tillage increases crop biomass production and...

Soil Carbon Measurements

Soil C measurements (Zt) may be made each year or less frequently, but measurements of R are not possible. Thus, the model has two variables that are to be estimated, but only one is observable. Furthermore, it is assumed that the SOC measurement error is normally distributed, independent in time and independent from X and R. A time series of measurements was generated using two steps to demonstrate the approach. First, a time series of true values of SOC (Xt) was computed using Equation 16.1...

Geographic Variability

The impacts of global warming will vary a great deal from one region to another. That means that the policies appropriate for one region may not be appropriate for another. Similarly, the institutional arrangements available for addressing the problems of global warming will also vary a great deal. This includes the capability of markets to perform efficiently, and thus the efficiency and effectiveness with which markets can bring resources to bear on the problem. In the developed Organization...

Increasing Carbon Sequestration through Nutrient Recapitalization and Agroforestry

Throughout Sub-Saharan Africa there is a constant threat of famine because of declining crop yields, depletion of soil nutrients, and reduced C stover of soils. The direct subsidy of inorganic fertilizers and nutrient or nutrient recapitalization has been adopted to combat nutrient depletion in smallholder farming systems (Mokwunye, 1995). Nutrient capitalization enhances crop productivity, which then contributes to soil C sequestration from stover, and stubble and root incorporation, as well...

Long Term Effects on Agriculture Are Negative

If the effects of climate change are not abated, even production in the mid- and high-latitude regions is likely to decline in the long term (end of 21st century) (Figure 10.5). These results are consistent over a range of temperature, precipitation, and direct CO2 effects tested, and are due primarily to the detrimental effects of heat and water stress as temperatures rise. While the beneficial effects of CO2 will eventually level out, the detrimental effects of warmer temperatures and greater...

Assessing Food Security with the Food Security Assessment Model

The food security assessment (FSA) model, developed by the U.S. Department of Agriculture's (USDA) Economic Research Service (ERS), assesses food security at the country level and within country by income groups in order to account for both physical access (food availability) and economic access to food (see USDA, ERS, 2003 for details). The commodity coverage in this analysis includes grains, root crops, and other crops. Together, these three commodity groups account for 100 of all calories...

El Nio Southern Oscillation

The El Ni o-Southern Oscillation (ENSO) is a large-scale ocean-atmosphere, quasi-regular interaction in the Pacific Ocean, which has reverberations in the climate system worldwide. These climate teleconnections bring droughts and floods to many agricultural regions, especially in the tropics, but to some degree in mid-latitudes as well. During an El Ni o event, droughts tend to occur in Northeast Brazil, Australia, Indonesia, and southern Africa, among other locations, while floods tend to...

Study Area

Jessenia Bataua Images

Nova Vida Ranch (Figure 9.1) covers an area of 22,000 ha, and is a mixture of native forest and well-managed pastures of various ages. The climate of the region is humid tropical, with a dry season from May to September. Annual rainfall is 2200 mm. Annual mean temperature is 25.6 C. Mean temperature for the warmest and coolest months varies by less than 5 C, and mean annual relative humidity is 89 (Bastos and Diniz, 1982). Soils are classified as Podzolicos Vermelho-Amarelo (Red-Yellow...

Recommendations

Soil organic carbon content decreased over the period (1962 to 2002) depending on the agroclimatic zone and land use. In the Lake Victoria Basin, the relative decline was of 50 , 27 , 21 , and 12 for annual crops, banana, coffee, and range lands, respectively. 2. Under average climatic conditions, perennial crops have higher potential for soil organic carbon sequestration than annual crops in Uganda's subhumid agroclimatic zone of the Lake Victoria crescent. 3. There is great potential for...

Methods

Ecosystem manipulations, including studies with elevated CO2, temperature, and water or nitrogen additions provide insights into physiological, ecological, and biogeochemical processes underlying carbon storage. Long-term monitoring of ecosystem carbon fluxes and how they vary annually and seasonally with climate and between ecosystems with different environmental conditions also provide valuable information. This information must be extrapolated to regional and global scales. The terrestrial...

New Policy Perspective

The world continues to drift along with growing evidence that global warming is a fact, even though we do not fully understand what is causing that warming. Moreover, it has been difficult to mobilize globally the political support to do anything about it. For the most part, we rely on the volunteer efforts of national governments to take whatever steps they can find political support for. The Koyoto Protocol was designed to move us one step further toward collective action, but the reticence...

Characteristics of Mitigation Options

Forest protection as a strategy can ensure that the area under national parks remains at 5,942,000 ha up to the year 2030. Increased efficiency in forest management, harvesting, and utilization of forest products will also be necessary. The goal is to reduce deforestation to the barest minimum by reducing the production of firewood, charcoal, timber, and clearing for agriculture. Factors that contribute to the magnitude of C losses from soil are initial C stocks, texture, climate, slope, and...

Elevated Co2

One might expect that on nutrient deficient soils, the stimulation of tree growth should abate as forests outpace the capacity of soils to provide N and other nutrients. Oren et al. (2001) and Finzi et al. (2002) have demonstrated that at least early in the loblolly pine FACE experiment, the growth of pine trees is co-limited by CO2 and N. The N and C cycles are tightly coupled, and it has been hypothesized that elevated CO2, by increasing carbon and decreasing the N concentration of foliage,...

Impact

Research about the projected impacts of climate change provides a predictive understanding of the processes involved and their consequences. Many models used to predict impacts of climate change are based on obsolete primary tropical data sets. These data often keep being recycled in climate change studies, creating self-evident truths by continued quoting. Some studies acknowledge that such data sets are admittedly inadequate, but researchers continue to use them because they are unable to...

Section Iv Soil Carbon Dynamics and Farming Cropping Systems

Soil Carbon Sequestration Understanding and Predicting Responses to Soil, Climate, and James W. Jones, Valerie Walen, Mamadou Doumbia, and Arjan J. Gijsman Reducing Greenhouse Warming Potential by Carbon Sequestration in Soils Opportunities, Limits, and Management Practices and Carbon Losses via Sediment and Subsurface Lloyd B. Owens and Martin J. Shipitalo Measuring and Monitoring Soil Carbon Sequestration at the Project Dynamics of Carbon Sequestration in Various Agroclimatic Zones of Moses...

Impacts of Climate Change

11.4.2.1 Impacts on Crops and Livestock Major advances were made since the SAR in the understanding of how changes in climate elements such as temperature, precipitation, and humidity, are likely to affect crop plants and livestock CO2 direct effects were included in much of this new crop research. A review of 43 crop modeling studies performed since the SAR revealed important geographic differences in the predicted impact of climate change on yields (Gitay et al., 2001, Table 5.3). The studies...

Model Description

Many direct and indirect interactions among interacting ecosystem processes result in responses to changing environmental conditions at many different scales of time and space. Large-scale responses over several years pose the greatest challenges to elucidate and quantify. We used the global terrestrial ecosystem carbon (GTEC) model to analyze terrestrial carbon storage and exchange with the atmosphere over the 1930-2100 period. In this model, the carbon dynamics of each 1 latitude by 1...