CIESIN Reproduced, with permission, from: Ruttan, V. 1992. Issues and priorities for the twenty-first century. In Sustainable agriculture and the environment: Perspectives on growth and constraints, ed. V. Ruttan, 177-83. Boulder, CO: Westview Press.

Sustainable Agriculture and the Environment

Perspectives on Growth and Constraints


Vernon W. Ruttan

Issues and Priorities for the Twenty-first Century

When we look even further into the next century, there is a growing concern, as noted earlier, with the impact of a series of resource and environmental constraints that may seriously impinge on our capacity to sustain growth in agricultural production. One set of concerns centers on the environmental impacts of agricultural intensification. These include groundwater contamination from plant nutrients and pesticides, soil erosion and salinization, the growing resistance of insect pests and pathogens and weeds to present methods of control, and the contribution of agricultural production and land-use changes to global climate change. The second set of concerns stems from the effects of industrial intensification on global climate change. It will be useful before presenting some of the findings of these conversations to briefly characterize our state of knowledge about global climate change.

There no longer can be any question that the accumulation of carbon dioxide (CO2) and other greenhouse gasses -- principally methane (CH4), nitrous oxide (N2O), and chlorofluorocarbons (CFCs) - has set in motion a process that will result in some rise in global average surface temperatures over the next 30-60 years. Substantial disagreement is evident about whether warming due to greenhouse gasses has already been detected. And great uncertainty continues about the increases in temperature that can be expected to occur at any particular date or location in the future.

The several greenhouse gases differ with respect to (a) their radiative properties, (b) their different lifetimes in the atmosphere, and (c) the extent to which they undergo chemical transformation into other substances. Estimates reported by the U.S. Department of Agriculture (see Fig. 2), based on radiative properties, suggest that carbon dioxide accounts for roughly half the radiative forcing of global climate change. Other estimates, which take into account the different lifetimes and the chemical transformations, project a larger contribution from carbon dioxide and a smaller contribution to radiative forcing of climate change than the approach employed by Hanson (Lashoff and Ahuja, 1990; Nordhaus, 1990).

Most carbon dioxide emissions come from fossil fuel consumption. Biomass burning, cultivated soils, natural soils, and fertilizers account for close to half the nitrous oxide emissions. Most known sources of methane are a product of agricultural activities, principally, enteric fermentation in ruminant animals, release of methane from rice fields and other wetlands, and biomass burning. Estimates of nitrous oxide and methane sources, however, have a very fragile empirical base.

On a regional basis the United States contributes about 20 percent and western and eastern Europe and the USSR about 30 percent of greenhouse gas radiative forcing. In the near future contributions to radiative forcing from Third World countries are expected to exceed that of the OECD and the former centrally planned economies. Calculations based on radiative properties of several greenhouse gasses suggest that land use transformation and agricultural production could account for as much as 25 percent of the forcing of global climate change (Figure 2). It is apparent that calculations taking into account the different lifetimes and chemical transformation of the several greenhouse gasses would attribute to a somewhat smaller share of climate change forcing to agricultural sources.

During the conversations, Rayner, as well as several other participants, characterized the alternative policy approaches to the threat of global warming as preventivist and adaptionist. A preventivist approach could involve five policy options: reduction in fossil fuel use or capture of CO2 emissions at the point of fossil fuel combustion; reduction in the intensity of agricultural production; reduction of biomass burning; expansion of biomass production; and energy conservation.

The simple enumeration of these policy options should be enough to suggest considerable caution about assuming that radiative forcing will be limited to anywhere near present levels. Fossil fuel use will be driven, on the demand side, largely by the rate of economic growth in the Third World and by improvements in energy efficiency in the developed and the former centrally planned economies. On the supply side it will be constrained by the rate at which alternative energy sources are substituted for fossil fuels. Of these, only energy efficiency and conservation are likely to make any significant contribution over the next generation. The speed with which it will occur will be limited by the pace of capital replacement. Significant reversal of agricultural intensification, reduction in biomass burning, or increase in biomass absorption is unlikely to be realized within the next generation. The institutional infrastructure or institutional resources that would be required do not exist and will not be put in place rapidly enough to make a significant difference.

This forces me to adopt an adaptionist approach in attempting to assess the implications of global climate change for future agricultural research agendas. It also forces me to agree, as Abrahamson has insisted, that we will not be able to rely solely on a technological fix to the global warming problem. The fixes, whether driven by preventivist or adaptionist strategies, must be both technological and institutional.

An adaptionist strategy implies moving as rapidly as possible to design and put in place the institutions needed to remove the constraints that intensification of agricultural production are currently imposing on sustainable increases in agricultural production. Examples would include (a) the policies and institutions needed to rationalize water use in areas such as the western United States and the Indus Basin; (b) management of the use and development of coastal wetlands and shorelands to limit contemporary losses to property and human life; (c) strategies to deal with groundwater management, including the effect of pollution resulting from agricultural intensification. If we are successful in designing the institutions and implementing the policies needed to confront these and other contemporary problems, we will be in a better position to respond to the more uncertain changes that will emerge as the result of future global climate change.

The following research implications emerged from the conversations:

1. A serious effort should be initiated to develop alternative land use, farming systems, and food systems scenarios for the 21st century. A clearer picture of the demands that are likely to be placed on agriculture over the next century, and of the ways in which agricultural systems might be able to meet such demands, has yet to be produced. World population could rise from the present 5 billion level to the 10-20 billion range. The demands that will be placed on agriculture will also depend on the rate of growth of income, particularly in the poor countries where consumers spend a relatively large share of income growth on subsistence: food, clothing, and housing. The resources and technology that will be used to increase agricultural production by a multiple of 3-6 will depend on both the constraints on resource availability that are likely to emerge and the rate of advance in knowledge. Advances in knowledge can permit the substitution of more abundant for increasingly scarce resources and reduce the resource constraints on commodity production. Past studies of potential climate change effects on agriculture have given insufficient attention to adaptive change in non-climate parameters. But the application of advances in biological and chemical technology (which substitute knowledge for land), and advances in mechanical and engineering technology (which substitute knowledge for labor) have, in the past, been driven by increasingly favorable access to energy resources by declining prices of energy. It is not unreasonable to anticipate that there will be strong incentive, by the early decades of the next century, to improve energy efficiency in agricultural production and utilization. Particular attention should be given to alternative and competing uses of land. Land-use transformation, from forest to agriculture, is presently contributing to radiative forcing through release of CO2 and methane into the atmosphere. Conversion of low-intensity agricultural systems to forest has been proposed as a method of absorbing CO2. There also will be increasing demands on land use for watershed protection and for biomass energy production.

2. The capacity to monitor the agricultural sources and impacts of environmental change should be strengthened. It is a matter of serious concern that only in the last decade and a half has it been possible to estimate the magnitude and productivity effects of soil loss in the United States. Even rudimentary data on effects of soil loss production are almost completely unavailable in most developing countries. The same point holds, with even greater force, for groundwater pollution, salinization, species loss and others. It is time to design the elements of a comprehensive agriculturally related resource monitoring system and to establish priorities for implementation. Data on the effects of environmental change on the health of individuals and communities are even less adequate. The monitoring effort should include a major focus on the effects of environmental change on human populations. Lack of firm knowledge about the contribution of agricultural practices to the methane and nitrous oxide sources of greenhouse forcing was mentioned several times. Much closer collaboration is essential among production-oriented agricultural scientists, ecological-trained biological scientists, and the physical scientists who have been traditionally concerned with global climate change. This effort should be explicitly linked with the monitoring efforts currently being pursued under the auspices of the International Geosphere-Biosphere Programs (IGBP).

3. The design of technologies and institutions to achieve more efficient management of surface and groundwater resources will become increasingly important. During the twenty-first century water resources will become an increasingly serious constraint on agricultural production. Agricultural production is a major source of decline in the quality of both ground and surface water. Limited access to clean and uncontaminated water supply is a major source of disease and poor health in many parts of the developing world and in the former centrally planned economies. Global climate change can be expected to have a major differential impact on water availability, water demand, erosion, salinization, and flooding. The development and introduction of technologies and management systems that enhance water-use efficiency represents a high priority because of both short- and intermediate-run constraints on water availability, and the longer run possibility of seasonal and geographical shifts in water availability. The identification, breeding, and introduction of water efficient crops for dry land and saline environments is potentially an important aspect of achieving greater water-use efficiency.

4. The modeling of the sources and impacts of climate change must become more sophisticated. One problem with both physical and economic modeling efforts is that they have tended to be excessively resistant to advances in micro-level knowledge in the failure to take into consideration climate change response possibilities from agricultural research, and in the response behavior of decision-making units, such as governments, agricultural producers, and consumers.

5. Research on environmentally compatible farming systems should be intensified. In agriculture, as in the energy field, a number of technical and institutional innovations could have both economic and environmental benefits. Among the technical possibilities is the design of new "third" or "fourth" generation chemical, biorational, and biological pest management technologies. Another is the design of land-use technologies and institutes that will contribute to the reduction of erosion, salinization, and groundwater pollution.

6. Intermediate efforts should be made to reform agricultural commodity and income support policies. In both developed and developing countries, producers' decisions on land management, farming systems, and use of technical inputs (such as fertilizers and pesticides) are influenced by government interventions, such as, price supports and subsidies, programs to promote or limit production, and tax incentives and penalties. It is increasingly important that such interventions be designed to take into account the environmental consequences of decisions by land owners and producers induced by the interventions.

7. Alternative food systems win have to be developed. A food-system perspective should become an organizing principle for improvements in the performance of existing systems and for the design of new systems. The agricultural science community should be prepared, by the second quarter of the next century, to contribute to the design of alternative food systems. Many alternatives will include the use of plants other than the grain crops that now account for a major share of world feed and food production. Some alternatives will involve radical changes in food sources. Rogoff and Rawlins (1989) have described one such system that is based on lignocellulose, both for animal production and human consumption.

8. A major research program on incentive compatible institutional design should be initiated. Large-scale program of research on the design of institutions capable of implementing incentive- compatible resource management policies and programs should be initiated. By incentive compatible institutions I mean institutions capable of achieving compatibility between individual, organizational, and social objectives. A major source of the global warming and environmental pollution problem is the direct result of the operations of institutions that induce behavior by individuals, and of public agencies that are not compatible with societal development -- some might say survival -- goals. In the absence of more efficient incentive-compatible institutional design, the transaction costs involved in ad hoc approaches are likely to be enormous.


Lashoff, D.A., and D. Ahuja. 1990. Relative contributions of greenhouse gas emissions to global warming. Nature 344: 213-242.

Nordhaus, W.D. 1990. To slow or Not to Slow: The Economics of the Greenhouse Effect. NewHaven: Department of Economics, Yale University.

Rogoff,M.H. and S.L. Rawlins. 1987. Food Security: A technological alternative. BioScience 37: 800-807.