RESUMEN
Industrialization and urbanization, as a result of rapid economic development, have led to the deterioration of water quality in many rivers in developing countries. The Kelani River in Sri Lanka provides drinking water to Colombo and a range of market and non-market ecosystem services; but these services are threatened by deteriorating water quality. We apply a hydro-economic model that accounts for spatial patterns of water quality and abatement cost variability between firms in the catchment. The hydro-economic model combines a hydrological model of water quality with an economic optimization model to determine a cost-effective policy under alternate policy regimes. These include: the existing policy based on effluent concentration standards, effluent trading and effluent trading with multiple zones and an effluent tax. Tradeable permits with multiple zones are the least cost policy option that accounts for both spatial externalities and abatement costs. However, given current institutional capabilities, an effluent tax would be a more realistic second best policy as a transition from the current policy of effluent concentration standards to a policy based on the quantity of effluents.
Asunto(s)
Países en Desarrollo , Modelos Económicos , Calidad del Agua , Ríos , Sri LankaRESUMEN
We develop and use an empirically based model, which integrates fishing behaviour and a coral reef system, to evaluate outcomes from site closure strategies to manage the effects of recreational fishing. The model is designed to estimate management effects in complex settings with two-way feedback effects (between fishing and ecosystem dynamics) as well as spillover effects where the closure of a site (or sites) leads to the redistribution of fishing effort. An iconic coral reef system is used as a case study. The results demonstrate that some site closure strategies provide little incremental benefits over less stringent approaches. They also show that some strategies targeting more sites are actually inferior to more limited strategies, demonstrating that, in the analysis of complex problems involving feedback effects and substitutions, there is little substitute for the use of empirically based and sound modelling as the basis for informed conservation decision making and stakeholder consultation. These findings have direct relevance not only for policies aimed at improving recreational fishing management but also for securing the supply of marine ecosystem services.
Asunto(s)
Conservación de los Recursos Naturales , Explotaciones Pesqueras , Recreación , Animales , Arrecifes de Coral , Ecosistema , PecesRESUMEN
Water quality of the Kelani River has become a critical issue in Sri Lanka due to the high cost of maintaining drinking water standards and the market and non-market costs of deteriorating river ecosystem services. By integrating a catchment model with a river model of water quality, we developed a method to estimate the effect of pollution sources on ambient water quality. Using integrated model simulations, we estimate (1) the relative contribution from point (industrial and domestic) and non-point sources (river catchment) to river water quality and (2) pollutant transfer coefficients for zones along the lower section of the river. Transfer coefficients provide the basis for policy analyses in relation to the location of new industries and the setting of priorities for industrial pollution control. They also offer valuable information to design socially optimal economic policy to manage industrialized river catchments.
Asunto(s)
Monitoreo del Ambiente , Contaminantes Químicos del Agua/análisis , Ecosistema , Agua Dulce , Residuos Industriales , Industrias , Ríos/química , Sri Lanka , Contaminación del Agua/análisis , Contaminación del Agua/estadística & datos numéricos , Calidad del AguaRESUMEN
This study reviewed 62 economic analyses published between 1995 and 2014 on the economic impacts of policies that incentivise agricultural greenhouse (GHG) mitigation. Typically, biophysical models are used to evaluate the changes in GHG mitigation that result from landholders changing their farm and land management practices. The estimated results of biophysical models are then integrated with economic models to simulate the costs of different policy scenarios to production systems. The cost estimates vary between $3 and $130/t CO2 equivalent in 2012 US dollars, depending on the mitigation strategies, spatial locations, and policy scenarios considered. Most studies assessed the consequences of a single, rather than multiple, mitigation strategies, and few considered the co-benefits of carbon farming. These omissions could challenge the reality and robustness of the studies' results. One of the biggest challenges facing agricultural economists is to assess the full extent of the trade-offs involved in carbon farming. We need to improve our biophysical knowledge about carbon farming co-benefits, predict the economic impacts of employing multiple strategies and policy incentives, and develop the associated integrated models, to estimate the full costs and benefits of agricultural GHG mitigation to farmers and the rest of society.