Environmental and economic impacts of water scarcity and market reform on the Mooki catchment

Over-allocation of irrigation water has led to widespread environmental degradation in the Murray-Darling Basin (MDB) in Australia, prompting discussions of the water efficiency performance of irrigated industries. There is increasing pressure for irrigators to adopt water efficient practices in line with ecologically sustainable principles, especially with current drought conditions. However, there is great uncertainty surrounding the available practices to improve irrigation efficiency from both ecological and economic standpoints. This paper examines the economic and environmental impact of several possible water efficient practices and government policies, using an interdisciplinary approach combining biophysical modelling and economic modelling. This is done for the case-study of the Mooki catchment in the MDB, located in northern New South Wales, Australia.     

Environmental & economic life cycle assessment of current & future sewage sludge to energy technologies

The UK Water Industry currently generates approximately 800 GW h pa of electrical energy from sewage sludge. Traditionally energy recovery from sewage sludge features Anaerobic Digestion (AD) with biogas utilisation in combined heat and power (CHP) systems. However, the industry is evolving and a number of developments that extract more energy from sludge are either being implemented or are nearing full scale demonstration. This study compared five technology configurations: 1 – conventional AD with CHP, 2 – Thermal Hydrolysis Process (THP) AD with CHP, 3 – THP AD with bio-methane grid injection, 4 – THP AD with CHP followed by drying of digested sludge for solid fuel production, 5 – THP AD followed by drying, pyrolysis of the digested sludge and use of the both the biogas and the pyrolysis gas in a CHP.The economic and environmental Life Cycle Assessment (LCA) found that both the post AD drying options performed well but the option used to create a solid fuel to displace coal (configuration 4) was the most sustainable solution economically and environmentally, closely followed by the pyrolysis configuration (5). Application of THP improves the financial and environmental performance compared with conventional AD. Producing bio-methane for grid injection (configuration 3) is attractive financially but has the worst environmental impact of all the scenarios, suggesting that the current UK financial incentive policy for bio-methane is not driving best environmental practice. It is clear that new and improving processes and technologies are enabling significant opportunities for further energy recovery from sludge; LCA provides tools for determining the best overall options for particular situations and allows innovation resources and investment to be focused accordingly.     

Price perceptions in water demand

Economists advocate for using the price mechanism to manage water scarcity, but complex nonlinear rate structures prevalent in markets for municipal water obscure price signals. We conduct a randomized field experiment that jointly elicits knowledge about the cost of water and examines the impact of improved information on demand by linking a survey to water billing records. Half of our sample of 30,000 single family homeowners are randomly sent an invitation to a survey that asks questions about the water bill and the costs of water-use activities (e.g. the cost of taking a shower), and subsequently provides personalized accurate information. Results show that consumers have poor information about the marginal price of water and overestimate the costs of using water. Respondents are relatively better informed about their total bill and water consumption. In aggregate, respondents increase water use in response to the survey, potentially due to learning that water is cheaper than they previously thought. Increased consumption is concentrated among low users who are more likely to over-estimate the costs of using water.     

西部生态环境现状的经济学分析

西部生态环境的恶化是一个人与自然叠加影响的历史过程，但人为对生态环境的影响却越来越大。本文试图从产权、、收入和寻租理论等方面来分析问题的根源，并提出了建立对策。     

The On-Ranch Economics of Riparian Zone Cattle Grazing Management

A simulation model of a cattle ranch based in southern Alberta, Canada was developed to evaluate the on-ranch economics of adopting different grazing management strategies to improve riparian grazing capacity in natural grass rangeland. Under low-cost scenarios, there are positive economic incentives to adopt strategies to maintain riparian zones that already have high grazing capacity. However, riparian zones that have declined to moderate or low grazing capacity may require additional economic incentives to encourage ranches to adopt more costly management strategies to improve the grazing capacity. The economic incentives to adopt costly management strategies are highly sensitive to the size and shape of the riparian zone and rates of grazing capacity decline or improvement.     

西方灾害经济学模型述评

对西方灾害经济学研究应用的模型技术进行了概略的综述,包括投入产出和线性规划相结合的模型、投入产出和生产函数相结合的模型、一般均衡模型、系统动力学模型以及社会核算矩阵模型五种,并对这些模型的优缺点进行了简要的评析．     

A proposed formal structure for assessing bear-human encounters

A formal model for the interaction of bear and hiker populations in national parks is developed. A number of alternative interactive scenarios are identified and some specific cases explored in detail. Some examples of the insights to be gained by the use of such a formal structure by park managers charged with the dual mandate of preservation of fauna and provision of safe recreational opportunities are presented. The entire problem is then discussed within the context of the more general tragedy of the commons problem.     

林火管理经济学的研究与探讨——多种防火要素投入的最佳组合

用经济学的观点分析了多种防火要素投入时的等减灾效益与等成本曲线,研究了多种防火要素之间的相互替代与边际替代率问题,提出了多种防火要素投入时最佳组合的判据。     

Evaluating the Role of Plantations as Carbon Sinks: An Example of an Integrative Approach from the Humid Tropics

/ Despite their fast growth, tropical plantations are a small sink of atmospheric carbon because they occupy only a small area in relation to other land uses worldwide. Proper design and management of plantations can increase biomass accumulation rates, making them more effective C sinks. However, fast-growing plantations can extract large amounts of nutrients from the soil, and site fertility declines may limit sustained plantation forestry after a few rotations. We measured aboveground biomass accumulation, carbon sequestration, and soil chemistry in three young plantations of 12 indigenous tree species in pure and mixed designs in the humid lowlands of Costa Rica. Annual biomass increments for the three mixed plantations ranged from 10-13 Mg/ha. The mixtures of four species gave higher biomass per hectare than that obtained by the sum of one fourth hectare of each species in pure plots. At this early age of the plantations, estimated annual C sequestration values were comparable to other reports from young plantations of exotic species commonly grown in the tropics. Four years after planting, decreases in soil nutrients were apparent in pure plots of some of the fastest growing species, while beneficial effects on soils were noted under other species. The mixed plots showed intermediate values for the nutrients examined and, sometimes, improved soil conditions. A mixture of fast and slower growing species yields products at different times, with the slower growing species constituting a longer term sink for fixed carbon. Examination of the role of tropical plantations as C sinks necessitates integrative approaches that consider rates of C sequestration, potential deleterious effects on ecosystem nutrients, and economic, social, and environmental constraints.KEY WORDS: Native trees; Aboveground biomass; Stem increments; Rotation length; Soil nutrients; Economics     

Neoliberal Style,the American Re-Generation,and Ecological Jeremiad in Thomas Friedman's “Code Green”

Emerging popular literature trumpeting the prospects for Manifest Destiny through a greener capitalism illustrates the re-emergence of American myth to explain chaotic times and uphold America's exceptional character. Today, this character is dominated ideologically by the rhetorical repertoire of neoliberal economics. In this essay, the author dissects neoliberal rhetorical style as articulated through national myth and ecological jeremiad in bestselling author Thomas Friedman's (2008) “Code Green” thesis. In Code Green, an American strategy for confronting the convergence of global warming, new economic competition abroad, and population growth, the author traces a mythic “evolution” in ecological jeremiad toward a sustainable free market frontier. Crafting a muscular yet ostensibly non-political rhetoric of individualist sacrifice and reward, Friedman refigures the dark side of Western-led globalization's past.