This study provides evidence on the effectiveness of community controls in regulating the use of common agricultural land in Côte d'Ivoire and tests for factors such as group size, ethnic and income heterogeneity of the group, income and resource stock levels, in explaining the variation in effectiveness across communities. The results indicate significant deterioration in community controls. These results point towards the need for a comprehensive policy framework towards agriculture in general and land tenure in particular. The study also finds that smaller and ethnically homogenous communities are better able to coordinate their actions, thereby internalizing a higher proportion of the value of land as a factor of agricultural production than their large ethnically heterogenous counterparts. No evidence is, however, found in favour of income heterogeneity hindering or facilitating collective action.

In this paper I analyze the forest and debt dynamics in a less developed country (LDC), where the former is a renewable resource and the latter's increase results from the interests to be paid on the current debt minus the balance of trade surplus. Agricultural and industrial goods are produced, and whereas the former requires the converted forest as an input, the latter does not. It transpires that the stock of debt is likely to increase infinitely without repudiation, whereas the stock of forest is likely to oscillate around an equilibrium level. Within this framework, I compare the effectiveness and enforceability of the debt-for-nature and the debt-for-development swaps with respect to tropical deforestation and debt burden issues. Some empirical evidence confirming the theoretical results is provided.

The notion of intertemporal h-option value is introduced to extend to environmental decision-making problems of the concept of quasi-option value, defined by Arrow and Fisher and Henry, whenever an individual faces imprecise information, or hard uncertainty, represented by a non-additive measure over events. Under hard uncertainty and irreversibility, the decision-maker faces the intertemporal h-option value, that is an uncertainty premium of preservation, which represents the gain from being able to learn about the future consequences of irreversible actions. The intertemporal h-option value is a correction factor that has to be taken into account in evaluating the total economic value of feasible actions.

This paper attempts to develop a dynamic model of optimal biodiversity preservation in a stylized ecosystem. Species richness (number of species) is used as a measure of diversity and its interactions with the resource stock, consumptive extraction and preservation efforts are explored using a two-state variable optimal control model. The analysis extends to the implications of a random threshold in species richness and the relationship between ecological and economic stability conditions. Dynamic paths and equilibrium characteristics are illustrated using numerical techniques.

This paper evaluates policies for addressing forest degradation in developing country hill areas, where agriculture is the major activity and villagers depend on forests for important economic inputs. Population growth, poverty, and open access probably explain most 'overuse' in such areas, but these are very difficult, long-term problems. The paper argues that under such conditions interim demand-side policies should be seriously considered, but the case is also made that the set of feasible instruments is quite small. Focusing on the case of Nepal, two instruments for reducing fuelwood demand – promotion of more efficient, wood-burning cookstoves and policies that reduce the prices of alternative fuels (e.g., through subsidies) – are evaluated. Using a simple analytical model and results from two household surveys conducted in Nepal, it is concluded that promoting improved stoves is a much more efficient and equitable instrument than, for example, subsidizing the major alternative fuel, which is kerosene. The cost of fuelwood saved using improved stoves is predicted to be a very low $2.77 per metric ton.

The environmental Kuznets curve (EKC) hypothesis proposes that there is an inverted U-shape relation between environmental degradation and income per capita. This has been taken to imply that economic growth will eventually redress the environmental impacts of the early stages of economic development. The literature on this issue has developed rapidly over the last few years. This paper examines whether progress has been made on both understanding the EKC phenomenon and on addressing the various criticisms raised against some of the empirical studies and their interpretation in the policy literature. Though basic EKC studies continue to be carried out, recent work has focused on the effect of a variety of conditioning variables on the environmental impact-GDP relationship. Some attempts have also been made to examine the history of the relationship in individual countries. The econometric techniques used have improved. However, empirical decompositions of the EKC into proximate or underlying causes are either limited in scope or non-systematic, and explicit testing of the various theoretical models has not yet been attempted.

This paper presents different substitution mechanisms which determine, in a theoretical framework, the conditions for long-term sustainable development. In a one-sector approach and in two versions of a multi-sector endogenous growth model, the accumulation and the substitution of man-made inputs for natural resources are analysed. Assuming man-made capital to be an output of a specific sector of the economy, the elasticities of substitution between the different inputs play a more complex role than suggested by the one-sector approach. According to the multi-sector models, the prediction of growth becoming sustainable emerges as realistic, provided that the sectoral adjustment costs in the economy are not too high.

This study examines, in a developing-country context, the nature of the linkages between deforestation, land degradation and the movement of population from one region to another. While it is usually hypothesized that environmental degradation leads to stress migration from rural areas, changes in institutional arrangements and the subsequent regeneration of land and water may change the situation, decreasing the attractiveness of the option to migrate. Primary data from six villages in Rajasthan (a region in Western India) are used to set up alternative models using OLS, logit and 3SLS systems methods to test alternative forms of the hypotheses. It is found that the proper specification of group property rights, as a consequence of the existence of non-governmental organizations, does reduce migration. Further, a household's decisions to migrate and/or to participate in common property right creation are interrelated, being parts of its labour force allocation decisions. Other variables influencing household decisions to participate are levels of asset ownership, degree of dependence on common land and level of education.

When decisions to intervene in different schistosomiasis severity states are taken in isolation, inefficiencies are unavoidable due to failure to take account of the synergy between community and facility level options. To date no studies have been conducted of the sequential nature of decision-making processes in schistosomiasis. The main aim of this study is to develop a methodology that could be used to compute the costs and health benefits of alternative strategies for ameliorating the burden of illness from schistosomiasis, with a view to determine that strategy which would produce the greatest excess of benefits over cost. In other words, the goal is to develop a conceptual framework that could be used to map out the most efficient path of options for intervention across a spectrum of schistosomiasis states - asymptomatic, mild, moderate, severe, and very severe.

A cost-utility decision analysis (CUDA) model was developed and applied to the population living within the schistosomiasis endemic region of Kenya covered by the Mwea Irrigation Scheme. Both primary and secondary level options were included in the analysis.

The main findings are as follows. Strategies involving treatment at the community level were generally superior to non-treatment community strategies. The selective population praziquantel chemotherapy (SPCPS) was found to be the optimal strategy. Mollusciciding strategies are the most cost-effective among the non-treatment strategies. The results of the sensitivity analyses were, however, mixed. The inconclusive nature of the results indicates that firm policy conclusions cannot be made on the basis of current epidemiological information, and more research is urgently required to establish both the validity and reliability of the health-related quality of life (HRQoL), and the Delphi technique (DT) measurements used in the study.

The use of trade measures for environmental purposes has given rise to a series of economic and legal issues. These are explored in the paper through an examination of the United States embargo on imports of shrimp from several countries for environmental reasons, currently being considered by a WTO dispute settlement panel. The paper examines the effect on competitiveness of compliance with the higher standard imposed by the US, the appropriateness of universalizing those standards, and whether the US action is consistent with WTO rules. The major findings are that, in the case of Trinidad, (a) the competitiveness of the affected fishermen was reduced, (b) the US regulation was inappropriate to the conditions which prevailed in the shrimp industry there, and (c) the US action was WTO inconsistent given current interpretation of WTO rules. The paper anticipates that the current case could lead to a review of WTO rules, in favour of the environment.

The paper discusses valuation issues in the context of climate change impact estimation. Issues addressed are aggregation of damage costs over diverse regions (particularly equity-weighting), differentiation of per-unit values, willingness to pay versus willingness to accept compensation as a basis for valuation, and accountability for impacts. Numerical illustrations show that the damage cost estimates are quite sensitive to the assumptions made on these issues.

As environmental goods such as fuelwood and fodder become more scarce, rural households in developing countries spend more time in their collection. It has been suggested that as a result households may reallocate labor away from own-farm agricultural production. This paper examines whether this is the case for a sample of agricultural households from rural Nepal. Cross-sectional estimates of agricultural labor demand equations give some indication that reallocation away from farm work may occur as environmental products become more scarce. However, these results disappear in random-effects estimation suggesting that time is instead reallocated from other activities or leisure. What little evidence there is for a labor reallocation from agriculture suggests that policies to relieve environmental good collection labor burdens should focus on leaf fodder and grass used as livestock feed rather than on fuelwood.

One of the first lessons that students of cost-benefit analysis (CBA) learn is to ask whether projects or policies which they are studying generate additional benefits or costs, relative to the status quo. They are also told to be very careful in defining the project/policy which is the subject of their analysis. In my view, the ecological concept of resilience fails the CBA test, when applied to the study of economic and social systems, because it offers no additional insights to those we have already, and appears to be poorly defined.

Mangrove ecosystems provide a wide range of market and non-market benefits to coastal communities in the developing world, yet they remain undervalued and overexploited in most regions where they are found. This paper analyzes the use and value of mangroves in Kosrae, Micronesia, where the population is largely dependent on the swamps for fuelwood and other ecosystem services, such as erosion control, storm protection, and nutrient flows to shoreline fisheries. The results show that mangroves on the island are worth between $666 thousand and $1 million per year (1996 prices) based on the net value of marketable products alone. In addition, household survey data suggest that the local people are willing to pay between $1 million and $1.26 million per year to protect and use mangrove swamps indefinitely. The results thus indicate that the population places some premium on the existence and indirect ecosystem services of mangroves, over and above the direct use values. Moreover, respondents generally favored—and were willing to pay more for—a tax system designed to manage and preserve the mangroves' direct and indirect services over a permit system focused only the allocation of direct use over time. Valuation analyses using revealed preference and contingent valuation methods lead to additional conclusions regarding the distribution of benefits, with poor households deriving more direct benefits from—but willing to pay less to protect—mangrove ecosystems.

This paper investigates the potential for economic policies to influence environmental outcomes in low-income agriculture. The analysis focuses on how changes in agricultural prices influence land-use decisions and environmental indicators. Tree-planting decisions of low-income farmers in the Philippines are examined using a stochastic dynamic household model. Empirical analysis and dynamic simulations demonstrate that changes in relative prices and relative price risks are important determinants of tree-planting decisions. Results show that small holders are sensitive to risks associated with tree crops, but that price risk is not an insurmountable barrier to tree crop adoption. The relationship between cropping patterns and two environmental indicators - erosion and species diversity - are discussed.