Cost-effective environmental policy: implications of induced technological change

Cost-effective environmental policy generally requires that all emission sources are faced with the same tax. In this paper I discuss how the existence of induced technological change may alter this result, if at least some of the effect is external to the firm. Focusing on Learning by doing (LBD) effects in abatement activities, it is shown that emission sources with external learning effects should be faced with a higher tax than emission sources with only autonomous technological change. By using simple numerical simulations, it is further investigated to what degree a cost-effective climate policy differs from a free quota market, under various assumptions about learning effects, diffusion of technology and environmental targets. The results indicate that optimal taxes may be significantly higher in the industrial world than in the developing world. Moreover, the industrial world's share of global abatement may be much higher in a cost-effective solution than in a free quota market. The global cost savings of a fully flexible implementation of the Kyoto Protocol are further questioned, as potential spillover effects of technological growth in the industrial world are not internalised in the market.     

Efficient statistical mapping of avian count data

We develop a spatial modeling framework for count data that is efficient to implement in high-dimensional prediction problems. We consider spectral parameterizations for the spatially varying mean of a Poisson model. The spectral parameterization of the spatial process is very computationally efficient, enabling effective estimation and prediction in large problems using Markov chain Monte Carlo techniques. We apply this model to creating avian relative abundance maps from North American Breeding Bird Survey (BBS) data. Variation in the ability of observers to count birds is modeled as spatially independent noise, resulting in over-dispersion relative to the Poisson assumption. This approach represents an improvement over existing approaches used for spatial modeling of BBS data which are either inefficient for continental scale modeling and prediction or fail to accommodate important distributional features of count data thus leading to inaccurate accounting of prediction uncertainty.     

Relating chronic toxicity responses to population-level effects: A comparison of population-level parameters for three salmon species as a function of low-level toxicity

Standard laboratory toxicity tests assess the physiological responses of individual organisms to exposure to toxic substances under controlled conditions. Time and space restrictions often prevent the assessment of population-level responses to a toxic substance. Contaminants can affect various biological functions (e.g. growth, fecundity or behavior), which may alter different demographic traits, leading to population-level impacts. In this study, immune suppression, reproductive dysfunction and somatic growth impairment were examined using life history matrix models for coho salmon (Oncorhynchus kisutch), sockeye salmon (Oncorhynchus nerka) and chinook salmon (Oncorhynchus tshawytscha). Our intent was to gauge the relative magnitude of response to toxic effects among species and between life history stages, not provide a specific estimate of population growth rate or abundance. Effects due to immune suppression were modeled as reductions in age-specific survival. Toxic impacts on reproductive function were modeled as a 10% reduction in reproductive contribution for all reproductively mature age groups. Model runs that examined the effect of somatic growth reduction on population parameters incorporated both survival and reproductive impacts. All impacts were modeled as 10% reductions in the affected population demographic parameters. First-year survival and reproductive impacts produced similar population growth rates (λ), but resulted in different sensitivity and stable age distributions. Modeled somatic growth reduction produced additive effects on survival and reproduction. Toxic stressors producing similar changes in λ did not necessarily produce similar changes in the age distributions. Sensitivity and elasticity analyses demonstrated that changes to the first-year survival rate produced the greatest per-unit effect on λ for each species. Alteration in abundance of mature females also strongly influenced λ. Differences observed between species showed that the number of reproductive ages and time to reproductive maturity were important components for population-level responses. These results emphasize the importance of linking toxicity responses at low concentrations to the demographic traits they affect, and help to highlight the toxicity tests that are more suitable for assessing impacts on the focal species. Additionally, life history modeling is a useful tool for developing testable hypotheses regarding impacts on specific populations as well as for conducting comparisons between populations.     

Sociological edge effects: Spatial distribution of human impact in suburban forest fragments

Suburban forest fragments often experience heavy recreational and waste disposal use, with considerable damage to the vegetation. To suggest strategies for conservation of the forest flora, spatial distributions of human impact were described in 40 fragmentary stands in northern New Castle County, Delaware. The distribution of human impact showed a significant bias to the forest edge, with 95% of localized damage occurring in the first 82 m. Forms of impact related to lawn maintenance fell significantly closer to the edge than impacts related to recreation and showed the strongest edge orientation. Edge distances of campsites, vandalized trees, and firewood gathering were negatively correlated with distance to the nearest graded road, indicating the importance of road access. Several forms of impact were also clustered near footpaths, although distance to paths was independent of edge distance in all cases. In terms of penetration of the forest and severity of damage, human impact greatly exceeds natural edge effects reported for this community. These findings suggest that damage may be minimized by limiting road access and avoiding the creation of small forest fragments.     

SPATIALLY OPTIMIZING FOREST MANAGEMENT SCHEDULES TO MEET STORMFLOW CONSTRAINTS1

ABSTRACT: A spatial optimization model is developed and used to limit cumulative effects resulting from storm events by strategically arranging and scheduling forest treatments to meet peak storm-flow constraints. A mixed integer forest management scheduling formulation is used to select the location and timing of forest treatments. The approach includes simulated spatial routing of storm-flows imbedded as hydrologic process constraints (in a nested schedule) within longer-term forest management planning periods in the mathematical programming model. Although difficult to solve, the model shows promise for further research.     

威廉腔环蚓(Metaphire guillelmi)对~(14)C-土壤有机质转化的研究

土壤有机碳是全球碳循环的重要组成部分,而大型土壤动物对土壤碳库的稳定性起着重要的决定作用。利用14C示踪技术,以14C-葡萄糖制备微生物源的土壤有机质(Soil organic matter,SOM),以蚯蚓威廉腔环蚓(Metaphire guillelmi)为代表,研究了14C-SOM在含有蚯蚓的两种土壤、不含蚯蚓的对照土壤和不含蚯蚓的蚓粪中的矿化、残留物在土壤和蚓粪中分布以及蚯蚓对14C-SOM的吸收。结果显示,15 d的培育期内蚯蚓显著加快了14C-SOM的矿化,在土壤中的矿化量是不含蚯蚓的对照土壤中矿化量的1.5～1.7倍,然而当移出蚯蚓后,残留14C-SOM在两种土壤中40 d内的矿化都比对照土壤中低。大约有4.2%～4.8%的14C-SOM被蚯蚓吸收利用。在有蚯蚓存在的土壤中,14C-SOM残留物在胡敏素中的含量有所增高,而在溶解有机物(DOM)中的含量显著降低。14C-SOM在不含蚯蚓的蚓粪中55 d内的矿化量和矿化动力学以及残留分布与在对照土壤中均没有显著区别。这些结果表明,蚯蚓对微生物源14C-SOM转化的影响主要是蚯蚓的肠道作用,这种作用可表现在两个方面,即初期对14C-SOM矿化的促进作...     

Occurrence and formation of disinfection by-products in the swimming pool environment: A critical review

Disinfection of water for human use is essential to protect against microbial disease; however, disinfection also leads to formation of disinfection by-products (DBPs), some of which are of health concern. From a chemical perspective, swimming pools are a complex matrix, with continual addition of a wide range of natural and anthropogenic chemicals via filling waters, disinfectant addition, pharmaceuticals and personal care products and human body excretions. Natural organic matter, trace amounts of DBPs and chlorine or chloramines may be introduced by the filling water, which is commonly disinfected distributed drinking water. Chlorine and/or bromine is continually introduced via the addition of chemical disinfectants to the pool. Human body excretions (sweat, urine and saliva) and pharmaceuticals and personal care products (sunscreens, cosmetics, hair products and lotions) are introduced by swimmers. High addition of disinfectant leads to a high formation of DBPs from reaction of some of the chemicals with the disinfectant. Swimming pool air is also of concern as volatile DBPs partition into the air above the pool. The presence of bromine leads to the formation of a wide range of bromo- and bromo/chloro-DBPs, and Br-DBPs are more toxic than their chlorinated analogues. This is particularly important for seawater-filled pools or pools using a bromine-based disinfectant. This review summarises chemical contaminants and DBPs in swimming pool waters, as well as in the air above pools. Factors that have been found to affect DBP formation in pools are discussed. The impact of the swimming pool environment on human health is reviewed.     

征税,还是补贴--对当前环境经济政策的反思

现行环境经济政策的目标在于纠正经济主体的外部不经济性，具体是通过税收或产权交易使外部成本内部化，本文称其为环境经济政策的“不对称性”。因为外部效应除了外部不经济以外，还有外部经济，现行的环境经济政策只考虑了前者却完全忽视了后者，只强调了外部成本的内部化却忽视了外部收益也应该内部化。以此为出发点，文章从现行政策的对立面出发，探讨了围绕外部收益内部化制定环境经济政策的必要性和可行性。最后作者分析了目前排污权交易存在的严重问题，并给出了解决问题的方法。     

A Spatiotemporal Analysis of Urban Growth:A Case Study for Jinan Municipality,China

China is experiencing a process of rapid industrialization and urbanization at the cost of agricultural land and environment,particularly in the costal areas. This study takes Jinan as a case presenting a time-series analysis of urban land expansion from 313 to 2003. The results show that the urban expansion of Jinan city mainly took place in the last 100 years, especially after the economic reform in 1978. Social development and economic growth,urban population growth and migration policies were factors driving the urban land expansion. Urban sprawl resulted in a disappearance of wetlands and a great loss of agricultural land, and over-pumping of ground water that led to disappearance of the city‘s feature,namely “the city of springs“.