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1.
We show that for a broad class of technologies the relationship between policy stringency and the rate of technology adoption is inverted U-shaped. This happens when the marginal abatement cost (MAC) curves of conventional and new technologies intersect, which invariably occurs when emissions are proportional to output and technological progress reduces emissions per output. This outcome does not result from policy failure. On the contrary, in social optimum, the relationship between the slope of the marginal damage curve and the rate of technology adoption is also inverted U-shaped. Under more general conditions, these curves can look even more complicated (e.g., such as inverted W-shaped).  相似文献   

2.
We show that for a broad class of technologies the relationship between policy stringency and the rate of technology adoption is inverted U-shaped. This happens when the marginal abatement cost (MAC) curves of conventional and new technologies intersect, which invariably occurs when emissions are proportional to output and technological progress reduces emissions per output. This outcome does not result from policy failure. On the contrary, in social optimum, the relationship between the slope of the marginal damage curve and the rate of technology adoption is also inverted U-shaped. Under more general conditions, these curves can look even more complicated (e.g., such as inverted W-shaped).  相似文献   

3.
In this paper, we consider a three-stage game in the context of a competing exporters model to compare and contrast the effects of discriminatory and uniform (Most Favored Nation, MFN) tariffs on countries’ choice over environmental standards for varying degrees of pollution spillovers. Because of the presence of punishment effects and stronger own and cross-tariff effects, we find that discrimination yields higher standards than MFN (and free trade) independently of the extent of pollution spillovers. When pollution is local and incentives to free ride on other countries’ abatement efforts are weak, we show, however, that welfare is larger under MFN than under discrimination. In a dynamic setting, we consider the impact of symmetric and asymmetric treatments on the sustainability of an international environmental agreement (IEA) and obtain that multilateral cooperation is easier to sustain under discrimination than under MFN (or free trade).  相似文献   

4.
Developing countries, including China, are just beginning to figure out how to balance economic development with the desire to address numerous severe environmental problems. In this paper, we use two enterprise-level data sets – China's Environmental Statistics Database and China's Industrial Enterprise Database – to estimate the impact of a more stringent wastewater discharge standard imposed on all the textile printing and dyeing enterprises in the Lake Tai, Jiangsu region, on labor demand. We find that enterprises which face this new more stringent standard decreased labor demand by approximately 7%. Furthermore, we find that the new standard had heterogeneous impacts on different types of enterprises. For example, our results indicate that the more stringent discharge standard reduced employment in domestically-owned private enterprises by 7.4%, but had little or no impact on state-owned or foreign-owned enterprises.  相似文献   

5.
Environmental Geochemistry and Health - The environmental inequality theory reveals that the risk of environmental pollution exposure varies among regions and groups and that particular groups face...  相似文献   

6.
Encouraging the use of more efficient irrigation technology is often viewed as an effective, politically feasible method to reduce the consumptive use of water for agricultural production. Despite its pervasive recommendation, it is not clear that increasing irrigation efficiency will lead to water conservation in practice. In this paper, we evaluate the effect of a widespread conversion from traditional center pivot irrigation systems to higher efficiency dropped-nozzle center pivot systems that has occurred in western Kansas. State and national cost-share programs subsidized the conversion. On an average, the intended reduction in groundwater use did not occur; the shift to more efficient irrigation technology has increased groundwater extraction, in part due to shifting crop patterns.  相似文献   

7.
Wang JM  Firestone MK  Beissinger SR 《Ecology》2011,92(5):1137-1145
The viability of freshly laid avian eggs declines after several days of exposure to ambient temperatures above physiological zero, and declines occur faster in tropical than temperate ecosystems. Microbial infection during preincubation exposure has recently been shown as a second cause of egg viability decline in the tropics, but whether microbial processes influence the viability of wild bird eggs in temperate ecosystems is unknown. We determined the microbial load on eggshells, the incidence of microbial penetration of egg contents, and changes in the viability of wild bird eggs (Sialia mexicana, Tachycineta bicolor, Tachycineta thalassina) experimentally exposed to temperate-zone ambient conditions in situ in a mediterranean climate in northern California. Initial microbial loads on eggshells were generally low, although they were significantly higher on eggs laid in old boxes than in new boxes. Eggshell microbial loads did not increase with exposure to ambient conditions, were not reduced by twice-daily disinfection with alcohol, and were unaffected by parental incubation. The rate of microbial penetration into egg contents was low and unaffected by the duration of exposure. Nevertheless, egg viability declined very gradually and significantly with exposure duration, and the rate of decline differed among species. In contrast to studies performed in the tropics, we found little evidence that temperature or microbial mechanisms of egg viability decline were important at our temperate-zone site; neither temperatures above physiological zero nor alcohol disinfection was significantly related to hatching success. Delaying the onset of incubation until the penultimate or last egg of a clutch at our study site may maintain hatching synchrony without a large trade-off in egg viability. These results provide insight into the environmental mechanisms that may be responsible for large-scale latitudinal patterns in avian clutch size and hatching asynchrony.  相似文献   

8.
Hui C  McGeoch MA 《Ecology》2008,89(10):2946-2952
J. Harte et al. demonstrated that the power law form of the species-area relationship may be derived from a bisected, self-similar landscape and a community-level probability rule. Harte's self-similarity model has been widely applied in modeling species distributions. However, R. D. Maddux showed that this self-similarity model generates biologically unrealistic predictions. We resolve the Harte-Maddux debate by demonstrating that the problems identified by Maddux result from an assumption that the probability of occurrence of a species at one scale is independent of its probability of occurrence at the next. We refer to this as a "non-heritage assumption." By altering this assumption to one in which each species in the community has an occupancy status that is partially inherited across scales (a scale-heritage assumption), the predictions of the self-similarity model are neither mathematically inconsistent nor biologically unrealistic. Harte's self-similarity model remains an important framework for modeling species distributions. Our results illustrate the importance of considering patterns of species co-occurrence, and the way in which species occupancy patterns change with scale, when modeling species distributions.  相似文献   

9.
The quest for agricultural sustainability generates the need to develop functional support schemes aimed at supplying farmers with knowledge, information and appropriate solutions, thus smoothing the transition towards sustainable agriculture (SA). In this vein, it is expected that agronomists have to play a key role, plotting the course for a sustainable farming future. Nevertheless, a critical question is whether agronomists possess the skills and competencies needed to motivate and guide this transition process. Two studies were designed to examine which clusters of agronomists’ skills and competencies determine their ability to promote SA. Study 1, using data from a sample of farmers, revealed that agronomists’ level of knowledge on issues pertaining to SA, their networking capacities, facilitation competencies, and communication skills affect their ability to guide the transition towards sustainable farm production. Study 2, drawing on data from a sample of agronomists, confirmed the pivotal role of sustainability knowledge, facilitation skills and networking competencies on the aptitude to promote SA. Both studies uncovered that agronomists display low to moderate levels of these skills. Taken together, these results point out the need to reorganize agronomic (formal and lifelong) education in order to equip agronomists with new competencies and to enable them to effectively promote SA.  相似文献   

10.
The hedonic property value model is among our foremost tools for evaluating the economic consequences of policies that target the supply of local public goods, environmental services, and urban amenities. We design a theoretically consistent and empirically realistic Monte Carlo study of whether omitted variables seriously undermine the method’s ability to accurately identify economic values. Our results suggest that large gains in accuracy can be realized by moving from the standard linear specifications for the price function to a more flexible framework that uses a combination of spatial fixed effects, quasi-experimental identification, and temporal controls for housing market adjustment.  相似文献   

11.
Federal, state, and local governments use a variety of incentives to induce consumer adoption of hybrid-electric vehicles. We study the relative efficacy of state sales tax waivers, income tax credits, and non-tax incentives and find that the type of tax incentive offered is as important as the generosity of the incentive. Conditional on value, sales tax waivers are associated with more than a ten-fold increase in hybrid sales relative to income tax credits. In addition, we examine how adoption varies with fuel prices. Rising gasoline prices are associated with greater hybrid vehicle sales, but this effect operates almost entirely through high fuel-economy vehicles. By comparing consumer response to sales tax waivers and estimated future fuel savings, we estimate an implicit discount rate of 14.6% on future fuel savings.  相似文献   

12.
Abstract: It has been suggested that the keystone-species concept should be dropped from ecology and conservation, primarily because the concept is poorly defined. This prompted Power et al. (1996) to refine the definition: keystone species have large effects on community structure or ecosystem function (i.e., high overall importance), and this effect should be large relative to abundance (i.e., high community importance). Using prairie dogs ( Cynomys spp.) as an example, I review operational and conceptual difficulties encountered in applying this definition. As applied to prairie dogs, the implicit assumption that overall importance is a linear function of abundance is invalid. In addition, community importance is sensitive to abundance levels, the definition of community, and sampling scale. These problems arise largely from the equation for community importance, as used in conjunction with removal experiments at single abundance levels. I suggest that we shift from the current emphasis on the dualism between keystone and nonkeystone species and instead examine how overall and community importance vary (1) with abundance, (2) across spatial and temporal scales, and (3) under diverse ecological conditions. In addition, I propose that a third criterion be incorporated into the definition: keystone species perform roles not performed by other species or processes. Examination of how these factors vary among populations of keystone species should help identify the factors contributing to, or limiting, keystone-level functions, thereby increasing the usefulness of the keystone-species concept in ecology and conservation. Although the quantitative framework of Power et al. falls short of being fully operational, my conceptual guidelines may improve the usefulness of the keystone-species concept. Careful attention to the factors that limit keystone function will help avoid misplaced emphasis on keystone species at the expense of other species.  相似文献   

13.
14.
Endemic goitre was prevalent in the population of Derbyshire in the UK for many centuries until it declined from the 1930s. A contemporary medical survey showed that endemicity of goitre was particularly higher in the Carboniferous limestone areas of the Derbyshire-Peak District. Unlike classical goitrous areas of the world, where the distribution of goitre has been found to be related to the iodine content in the environment, there is no such relationship reported for the Derbyshire-Peak District area. The present study reviews the presence of endemic goitre in this area with reference to iodine in different environmental media using past and present data. In comparison with the world average values, the iodine contents in the soil and sediment in the Peak District are not deficient, but compared to England, Wales and Scotland averages, these levels are low. As no information on the mobility and bioavailability of iodine of this area is available, a cautious approach is necessary before any assumption is made on the aetiology of endemic goitre. The study also discusses some hypotheses relating to the possible cause of endemic goitre in the limestone areas. Further research needs are suggested depending on the land use and geochemistry of the Peak District to determine the underlying causes of the former endemic goitre in this area.  相似文献   

15.
This study assesses the role of trees in adaptation strategies of rural households to local environmental change in the central highlands of Ethiopia. Change in tree cover was assessed by producing Land Use and Land Cover (LULC) maps using satellite remote sensing images, and household survey was conducted to generate socioeconomic data. The results show that tree cover has increased over the last 30 years, mostly in the form of eucalyptus woodlots around homesteads. Eucalyptus reportedly helps households pass through livelihood shocks and provide protection against negative effects of climate change and variability. Despite some concerns on the part of local agricultural experts that planting eucalyptus may affect future food production, farmers are converting their croplands into eucalyptus woodlots. We conclude that land use planning and proper allocation of land resource is important to improve local livelihoods while also supporting adaptation of communities to local environmental change in general and climate change in particular.  相似文献   

16.
Lagoons are defined as wetlands separated from the sea coasts on which they are located and sit between continental and marine aquatic ecosystems. Çakalburnu Lagoon is a coastal wetland on the southern side of the Bay of ?zmir. Microorganisms, which are quite sensitive to changes occurring in environmental factors, are commonly used to determine the impact of environmental effects on the functioning of the ecosystem. In this study, variations in the abundance and biomass of picoplankton (Synechococcus spp. and bacteria) and the abundance of viruses, which identify the ecological productivity of the food chain, were seasonally examined by epifluorescence microscopy. Moreover, the microbial abundance and biomass relation over time between the physical and chemical parameters was evaluated. According to our results, the maximum abundance of Synechococcus spp. and viruses was 6.7?×?104 cell/ml and 9.9?×?108?cell/ml in the summer, respectively. Otherwise, the highest level of bacteria was measured at 3.6?×?107 cell/ml in the spring. Based on the principal component analysis and Pearson correlation analysis results, we concluded that total suspended solids, Chl-a, particulate organic carbon and particulate organic nitrogen were the major parameters influencing the observed variability of the lagoon system. Overall, to protect and improve the ecological and microbiological quality of aquatic systems such as lagoons, the necessary monitoring and measurement studies should be conducted in these sensitive areas.  相似文献   

17.
This paper explores the characteristics of 238 patents on 90 inventions contributed by major multinational innovators to the “Eco-Patent Commons”, which provides royalty-free access to third parties to patented innovations on green technologies. We compare the pledged patents to other patents in the same technologies or held by the same multinationals to investigate the motives of the contributing firms as well as the potential for such commons to encourage innovation and diffusion of climate change related technologies. We find pledged patents to protect environmentally friendly technologies and to be of similar value as the average patent in a pledging firm's patent portfolio but of lower value than other patents in their class. Our analysis of the impact of the patent commons on diffusion of patented technologies suggests that making patents accessible royalty-free did not result in any significant increase in diffusion as measured by citing patents. This study, therefore, indirectly provides evidence on the role of patents in the development and diffusion of green technologies.  相似文献   

18.
The chelating characteristics of nitrilotriacetic acid (NTA) are presented and illustrated with respect to its application in medicine, pharmacy, industry (including detergent formulations), agriculture, and the food industry. The analytical chemistry of NTA is presented with respect to its application as an analytical reagent as well as in the separation and determination of NTA itself. A brief account on the toxicology and bio‐environmental aspects of this chelating agent is also part of this review. Special attention is paid to the controversy generated around NTA and its trisodium salt as a possible substituent for phosphate in heavy‐duty detergent formulations. A table of stability constants for metal complexes of NTA (including mixed‐ligand species) is also presented.  相似文献   

19.
In several vertebrate taxa, males and females differ in the proportions of time they individually devote to vigilance, commonly attributed to sex differences in intra-specific competition or in absolute energy requirements. However, an effect of sex on collective vigilance is less often studied (and therefore rarely predicted), despite being relevant to any consideration of the adaptiveness of mixed- vs single-sex grouping. Controlling for group size, we studied the effect of sex on vigilance in the sexually dimorphic eastern grey kangaroo Macropus giganteus, analysing vigilance at two structural levels: individual vigilance and the group’s collective vigilance. Knowing that group members in this species tend to synchronise their bouts of vigilance, we tested (for the first time) whether sex affects the degree of synchrony between group members. We found that females were individually more vigilant than males and that their vigilance rate was unaffected by the presence of males. Collective vigilance did not differ between female-only and mixed-sex groups of the same size. Vigilance in mixed-sex groups was neither more nor less synchronous than in single-sex groups of females, and the presence of males seemed not to affect the degree of synchrony between females. Sixty-six percent of vigilant acts were unique (performed when no other kangaroo was alert), and only about one unique vigilant act in every three induced a collective wave of vigilance. The proportions of vigilant acts that were unique were 60% for females but only 46% for males. However, the sexes differed little in the rates at which their unique vigilant acts were copied. This limited study shows that the differences in vigilance between male and female kangaroos had no discernible effect upon collective vigilance.  相似文献   

20.
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