Section VI Toward Research and Development Priorities © 2005 by Taylor & Francis Group, LLC 729 30 Researchable Issues and Development Priorities for Countering Climate Change RATTAN LAL, B.A. STEWART, DAVID O. HANSEN, AND NORMAN UPHOFF CONTENTS 30.1 Issues 732 30.1.1 Climate Change and Net Primary Production 733 30.1.1.1 Climate Change: CO 2 Fertilization Impacts on Terrestrial Ecosystem Production 733 30.1.1.2 Climate Change Impacts on Forest Ecosystems 733 30.1.1.3 Climate Change Impacts on Water Supply 734 30.1.2 Global Warming and Food Insecurity 734 30.1.2.1 Greenhouse Gases and Food Security in Low-Income Countries 734 © 2005 by Taylor & Francis Group, LLC 730 Lal et al. 30.1.2.2 Effect of Global Climate Change on Agricultural Pests 734 30.1.2.3 Impact of Climate Change on Agricultural Production in Different Regions 735 30.1.2.4 Modeling Future Climate Changes and Crop Production Scenario Challenges 735 30.1.2.5 Policy Considerations Related to Twin Problems of Global Warming and Food Insecurity 736 30.1.3 Terrestrial Carbon Sequestration and Food Security 736 30.1.3.1 Environmental and Socioeconomic Context for Soil Carbon Sequestration 737 30.1.3.2 Land Use, Soil Management, and Soil Carbon Sequestration 737 30.1.3.3 Modeling and Extrapolating Soil Carbon Sequestration 738 30.1.3.4 Environmental and Socioeconomic Analysis of Soil Carbon Sequestration 738 30.1.4 Policy and Economic Issues 739 30.1.4.1 Policies and Incentives for Permanent Adoption of Agricultural Carbon Sequestration Practices in Industrialized and Developing Countries 739 30.1.4.2 Climate Change, Poverty, and Resource-Friendly Agriculture 740 30.1.4.3 Climate Change and Public Policy Challenges 741 30.1.4.4 Climate Change Impacts on Developing Countries 741 30.1.4.5 Climate Change and Tropical Agriculture: Implications for Social Vulnerability and Food Security 742 © 2005 by Taylor & Francis Group, LLC Researchable Issues and Development Priorities 731 30.2 Identification of Researchable Priorities 742 Acknowledgments 744 References 744 The globe has experienced a 31% increase in the atmospheric concentration of carbon dioxide (CO 2 ) and substantial increases in other greenhouse gases (GHGs) since the indus- trial revolution (Intergovernmental Panel on Climate Change [IPCC], 2001). The current rate of increase of CO 2 is about 0.5% or 1.5 ppm per annum. At this rate, the concentration of atmospheric CO 2 will double by the end of the 21st century. Environmental and related agricultural impacts of this increased concentration of CO 2 and other GHGs are subject to debate. But most would concur that several impacts will result, namely: •A rise in the mean global temperature, which will cause alterations in the amount and distribution of precipitation, and local, regional, and global changes in water and energy balances •A fertilization effect of increased atmospheric CO 2 on plant growth, with probable increases in biological productivity and water-use efficiency •A decrease in soil organic carbon (SOC) pools, accom- panied by a decline in soil quality and an increase in soil erosion and other degradation processes •An increase in the incidence of pests and pathogens with attendant adverse effects on crop yields and food production •Adverse effects on global food security, especially in tropical and subtropical regions that are character- ized by soils prone to degradation, large numbers of resource-poor farmers, and high demographic pressures Climate shifts have occurred almost constantly during the Earth’s history. However, the rate of projected change during the 21st century may be unprecedented. Interacting factors involved in this process are complex. However, it is © 2005 by Taylor & Francis Group, LLC 732 Lal et al. important to assess whether global agricultural production will increase or decrease, whether the quality of soil and water resources will improve or decline, whether the beneficial effects of CO 2 fertilization will be enhanced or nullified by other adverse impacts of global warming such as decline in soil quality, and whether food security will be jeopardized in regions with fragile soils and high population density. Anthropogenic activities, especially land use change and conversion of natural to agricultural ecosystems, have con- tributed to enrichment of GHGs in the atmosphere since the dawn of civilization (Ruddiman, 2003). Land use conversion and agricultural activities also adversely impacted soil qual- ity. Further, the atmospheric concentration of GHGs is also closely related to soil quality. A decline in soil quality, which results from accelerated erosion and the reduced soil fertility associated with subsistence farming, contributes to the release of CO 2 and other GHGs into the atmosphere. Since 1850, global terrestrial ecosystems have released 136 ± 55 Pg (billion metric tons) of C, while fossil fuel emissions have contributed 270 ± 30 Pg (IPCC, 2000). Regarding emissions from terrestrial ecosystems, reductions in the SOC pool rep- resent 78 ± 12 Pg (Lal, 1999). The conversion of natural eco- systems to agricultural ecosystems may have depleted as much as 30% to 50% of the SOC pools in the soils of temperate regions and 50% to 75% of those in the tropics (Paul et al., 1997; Lal, 1999, 2000). Depletion of the SOC pool is exacer- bated by erosion and soil degradation. Degraded soils in Sub- Saharan Africa and elsewhere in developing countries have low SOC pools because of nutrient mining and accelerated erosion. Enhancement of SOC pools through soil restoration would reverse degradation trends, improve soil quality, increase agronomic/biomass productivity, and mitigate cli- mate change. 30.1 ISSUES Several major issues related to projected climate changes need to be given greater attention in national and interna- tional fora. These issues are summarized below. © 2005 by Taylor & Francis Group, LLC Researchable Issues and Development Priorities 733 30.1.1 Climate Change and Net Primary Production Three globally significant issues are as follows: 30.1.1.1 Climate Change: CO 2 Fertilization Impacts on Terrestrial Ecosystem Production The relative contributions of CO 2 fertilization and climate change effects on terrestrial CO 2 sources and sinks have been estimated for different ecoregions. They suggest that the CO 2 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 NPP appear to be negative. Aggregate global impacts of CO 2 fertilization and climate change on CO 2 appear to be positive. Modeling results also suggest that the geographic dis- tribution of NPP will change along with changes in CO 2 and climate. Ecosystems with the highest NPP show the great- est change. The effects of other factors, such as land use history and nitrogen cycling, have generally not been con- sidered in these simulation models. They need to be care- fully assessed. 30.1.1.2 Climate Change Impacts on Forest Ecosystems Free-air CO 2 enrichment (FACE) experiments have shown that trees grow faster under elevated levels of CO 2 . These findings suggest that temperate forests may be stimulated by higher atmospheric CO 2 levels. However, data also suggest that tree growth may be negatively affected by increasing temperatures. In warmer climates, tropical forests could become a source rather than a sink for CO 2 . If all forests in the world were to experience stimulated growth from increased atmospheric CO 2 levels, the effect would be minor relative to CO 2 emissions from continued fossil fuel burning. © 2005 by Taylor & Francis Group, LLC 734 Lal et al. 30.1.1.3 Climate Change Impacts on Water Supply The potential impacts of climate change on global water sup- plies are of great importance. Results of a general circulation model (GCM) based on watershed data suggest that water flows will increase during the fall, winter, and spring seasons, but decrease during the summer. However, the increased demand for water associated with projected population increases will offset any additional water supplies over time. Future climate changes may reduce the carrying capacity of major reservoirs and water flows in rivers around the world because of large water demands for irrigated agriculture. 30.1.2 Global Warming and Food Insecurity Projected climate changes may adversely affect global and regional food security. 30.1.2.1 Greenhouse Gases and Food Security in Low-Income Countries Climate change may impact food security in different ways. Some parts of the world — notably West Africa — have already been adversely impacted by climate change. Signifi- cant differences in regional food gaps may be explained at least in part by higher levels of agricultural productivity in Latin America and Asia as compared to Sub-Saharan Africa. A major challenge facing food-deficit regions is to address long-term issues, such as global climate change, while also dealing with shorter-term issues such as availability of fertil- izers, farm machinery, land tenure, and so on. 30.1.2.2 Effect of Global Climate Change on Agricultural Pests The manner in which climate change will impact the incidence of pests and diseases is a potentially important but under- studied problem. Pest incidences may shift in response to climate change. The “standard model,” based on temperature © 2005 by Taylor & Francis Group, LLC Researchable Issues and Development Priorities 735 and precipitation, may be useful for studying impacts of cli- mate change, but much more research needs to be done. Most crop models that are used to predict impacts of climate change on production fail to incorporate pests. The problem is com- pounded by the complexity of the climate processes. Nitrogen appears to have important effects on insect herbivores and on important species interactions that are not well under- stood. It is also important to disconnect the scale at which tests are impacted by climate change from the scale used for GCM models. Pest–climate interactions with climate change need to be assessed. 30.1.2.3 Impact of Climate Change on Agricultural Production in Different Regions Projected climate changes could affect crop yields and soil carbon in different regions of the world. In fact, severe adverse impacts in the tropics could occur. Modeling studies based on data from Brazil show that changes in temperature and rain- fall may result in soybean production increases and maize and wheat production decreases by 2050. In a case study of the Amazon Basin in which forested areas were converted to pastureland, the soil carbon pool was projected to decrease by 30% over a 100-year period. A decline in the SOC pool would have adverse impacts on soil quality and result in a decline in agronomic productivity and the capacity of the environment to moderate changes. 30.1.2.4 Modeling Future Climate Changes and Crop Production Scenario Challenges The prediction of impacts of climate change on agricultural research and the use of crop models to assess the potential impacts of climate change suffer from several limitations. Crop models can result in accurate predictions when they are based on observed data, but are much less reliable when based on data that are downscaled from GCMs. A key limitation of GCM data appears to be an inability to represent extreme © 2005 by Taylor & Francis Group, LLC 736 Lal et al. weather events, particularly those associated with precipita- tion. The hydrological cycle in the U.S. Midwest is not well represented by downscaled GCM data, because of nonlinear and feedback effects in more detailed regional climate models. 30.1.2.5 Policy Considerations Related to Twin Problems of Global Warming and Food Insecurity There are major policy issues related to aspects of climate change. The world faces important food insecurity and global warming challenges in the 21st century. Previous research failed to suggest that global warming will have a large impact on aggregate food availability. However, it does suggest that global warming could have some major regional effects on food security, especially in the tropics, in which 800 million people are already at risk. The solution to the food security problem is to address the more fundamental problem of poverty. The “standard model,” based on the “Washington consensus,” may be the best starting point for economic development. This model emphasizes markets and institutions in infrastructure, education, and agricultural research. This model is not always used for political and cultural reasons. Nevertheless, past efforts indicate that an important step in promoting national food security is to develop economies to the point at which nations can afford to address environmental sustainability as well as economic growth. 30.1.3 Terrestrial Carbon Sequestration and Food Security Carbon sequestration in soil and vegetation, as well as tem- poral and spatial variations in relation to land use and man- agement and their related policy issues have major implications for global food security, climate change, and envi- ronmental quality. © 2005 by Taylor & Francis Group, LLC Researchable Issues and Development Priorities 737 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 atmospheric CO 2 and to reduce land degradation. The conservation of tropical forests and reforestation activities can offset fossil fuel use. In fact, drastic reductions in rates of deforestation are needed to protect the positive functions of tropical ecosystems. A serious problem of land degradation exists in the humid trop- ics, and there is an urgent need to find alternatives to slash- and-burn agriculture in this region. Similarly, SCS in coun- tries in the Sahel region may be an important way to increase carbon sinks, control desertification, and promote sustainable agriculture and improved livelihoods for its small farmers. Degraded lands have low soil C content. SOC concentration in degraded topsoils of Africa varies from 5 to 20 MT ha −1 . An urgent need exists to implement SCS practices in order to improve soil quality and farmer livelihoods while removing CO 2 from the atmosphere. 30.1.3.2 Land Use, Soil Management, and Soil Carbon Sequestration There are several examples of SOC sequestration from exper- iments that combine SCS practices with alternative food pro- duction systems. The rate of aboveground C sequestration ranges from 1 to 5 MT C ha −1 year −1 in the tropics, but C stocks associated with the traditional peanut-based cropping system in Sub-Saharan Africa ranged from 5 to 25 MT C ha −1 . The clay content in soils has a strong effect on C stocks. Overall rates of SCS in the tropics are lower than those found in higher latitudes (Lal, 2002). Most C accrual is accounted for by a limited number of plant species in agro- forestry systems that use fruit and palm trees, timber–pas- ture combinations, and secondary-growth forest. Soil C accrual rates are difficult to estimate due to the presence of charcoal in fire-prone or fire-dependent ecosystems, such as © 2005 by Taylor & Francis Group, LLC [...]... problem are needed 30.1.4.5 Climate Change and Tropical Agriculture: Implications for Social Vulnerability and Food Security Globalization may impact food security in developing countries The context for globalization and its impacts on people are frequently neglected Food security is also related to access to food Experience has shown that poor people in the tropics benefit less from globalization since these... region-specific, and they are defined in great measure by physiographic, soil, climate, sociocultural, 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. .. sequestration 30.1.4.3 Climate Change and Public Policy Challenges Several current treaties and conventions on climate change and biodiversity will be difficult to implement, and thus, they are unlikely to have much regional or global impact Changes are needed to improve related existing public policy climate These include: (1) greater cooperation among the various scientific disciplines; (2) expanded cooperation... world, and how might it change because of climate changes? Current information suggests that climate change impacts on food supply and demand vary across ecoregions Thus, it will be important to identify regions that may become food insecure and to formulate research and development strategies to address © 2005 by Taylor & Francis Group, LLC Researchable Issues and Development Priorities 743 the potential... 30.1.4.2 Climate Change, Poverty, and Resource-Friendly Agriculture A consensus exists regarding the need for changes in traditional agricultural practices that lead to soil degradation, including reductions in soil fertility and carbon content However, a major challenge faced by practitioners is the need to develop alternative farming systems for resource-poor farmers that enable them to achieve food security. .. 30.1.4 Policy and Economic Issues Policy and economic issues are important attempts to simultaneously address food insecurity, climate change, and reduced SCS Because these topics are interrelated, they must be addressed holistically using a multidisciplinary approach 30.1.4.1 Policies and Incentives for Permanent Adoption of Agricultural Carbon Sequestration Practices in Industrialized and Developing... for long-term research agendas, such as those of the Intergovernmental Panel on Climate Change, U.S National Academy of Science, and U.S Environment Protection Agency; (4) more policy-relevant applied research; and (5) more analysis of public policy anomalies Examples of the latter are latent policies that often conflict with official policies and special interest group objectives 30.1.4.4 Climate Change. .. land use and management strategies that will nullify the adverse impacts of climate change, maintain or enhance soil C pools, and sustain or improve soil quality This is an ambitious agenda, especially for regions with resource-poor farmers who cannot afford the inputs required to adopt the recommended management practices Understanding the magnitude and direction of the threeway interaction among climate. .. direction of the threeway interaction among climate change, soil C sequestration, and food security is crucial to addressing the global issue These interactive effects are specific to ecoregions/biomes, and require a holistic and multidisciplinary approach in order to develop specific studies with results that can be scaled up to watershed, regional, and global levels A great need exists for more local... sequestration and other forms of soil and water quality improvement These practices may need to be location-specific Simulation analyses suggest that payments for soil carbon sequestration may be insufficient to balance losses in agricultural production for small- and medium-scale farmers under tropical conditions On the other hand, alternative production practices hold great promise for increasing small-farm . Warming and Food Insecurity Projected climate changes may adversely affect global and regional food security. 30.1.2.1 Greenhouse Gases and Food Security in Low-Income Countries Climate change. impacts of climate change on food produc- tion. 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. 733 30.1.1.2 Climate Change Impacts on Forest Ecosystems 733 30.1.1.3 Climate Change Impacts on Water Supply 734 30.1.2 Global Warming and Food Insecurity 734 30.1.2.1 Greenhouse Gases and Food Security