Carbon taxation,OPEC and the end of oil

I develop a differential game between an oil cartel and an importer investing in research and development (R&D) to reduce the cost of a green substitute to oil. In equilibrium, the cartel is forced to deter the substitute, which thus imposes a price ceiling falling over time. Credible carbon taxes are below the Pigovian level, implying the importer cannot internalise the full pollution externality, much less capture resource rents. Without carbon pricing, the importer curtails long-run pollution using a costly R&D programme. Normatively, climate policy will be more expensive if relying on green R&D programmes only.     

A sustainability index for small island developing states

This paper proposes a novel approach to measuring the progress of small island developing states (SIDS) towards sustainable development (SD) as set by the UN Sustainable Development Goals 2030. Currently, these goals do not provide adequate guidance on how countries might measure their progress towards sustainability. We use these goals and a subset of their targets to develop an index with concrete targets, through the use of pertinent sustainability indicators, that SIDS should aim to achieve a sustainable society. In addition to the three categorical pillars of SD (social, economic and environmental), we included the category Climate Change and Disaster Management (incorporating Disaster Risk Reduction). The basis of our decision is that the UN and the Intergovernmental Panel on Climate Change have both recognized the vulnerability of SIDS to both environmental hazards. Our index scores a total 70 individual indicators for the four categories to track the progress of a SIDS towards a sustainable society. Using the Caribbean nation, Republic of Trinidad and Tobago, as our SIDS case study, we report the average of the scores for each category to illustrate its progress towards sustainability. Overall Trinidad and Tobago is slowly progressing towards a more sustainably developed society. Our results show that the nation is only moderately successful regarding progress in three traditional pillars of SD, social, economic and environmental. However, Trinidad and Tobago scores poorly in the Climate Change and Disaster Management category and needs to improve in this area especially due to its vulnerability.     

The challenge of sustainable development in small island developing states: case study on tourism in the Caribbean

Small island developing states (SIDS) in the Caribbean have long specialised in primary commodity exports, and traditional export sectors continue to be a major source of employment. The challenge of sustainable development for the Caribbean SIDS has two dimensions. The first is to adjust to the economic and social impact of the loss of preferential markets for traditional exports and of the dismantling of the ISI apparatus erected during the post-World War II period. The second is to ensure that existing and new patterns of production and consumption comply with the criteria for sustainable development, which is here defined as environmental, socio-cultural and economic sustainability.
This article outlines the potential contribution of sustainable tourism to the larger goal of sustainable development in the SIDS in the Caribbean. It reviews current literature on sustainable development and sustainable tourism, particularly their application to the Caribbean SIDS, and evaluates the Caribbean tourism industry from the point of view of sustainable tourism. Conclusions are drawn and proposals made for a policy-oriented agenda in support of the quest for sustainable tourism in the SIDS in the Caribbean.     

污染红利与污染集聚的机理与实证

文章用污染要素的替代效应与成本效应对污染集聚的形成机理进行了分析,研究结果说明污染红利会带来污染集聚.首先,污染替代效应会导致污染密集型产业成为主导产业;其次,污染成本效应一方面会导致单个企业排污加大,另一方面还会扩大污染密集型企业的数量;第三,污染替代效应和成本效应作为污染总效应的分支,二者的作用是累加的,不会互相抵消.为了检验该研究结论的正确性,本文用内蒙古工业规模效应、工业结构效应、工业科技效应指标对该省废气排放总量进行了回归分析,结果支持了上述研究结论.首先,有利于把污染当作红利使用的工业规模效应与工业科技效应均促进了废气排放的增加;其次,抑制把污染当作红利使用的工业结构效应则促进了废气排放的减少.因此,我国彻底治理环境污染是一项长期的任务,我们在加大产业结构调整的过程中,尤应加大对污染密集型产业的抑制.     

梁子湖水系湖泊营养状况的综合评价

用综合营养状态指数(TSIc),对梁子湖水系的4个湖泊营养状况进行了综合评价,并对4个湖泊的8项主要水化学指标进行了主成分分析。结果表明,洋澜湖、严家湖均呈富营养状态，武四湖、红莲湖分别呈中富营养及中营养状态。磷、硅对第1主成分贡献最大。氮对第2主成分贡献最大，4个湖泊的水质受水中磷含量影响最大。此外，4个湖泊中浮游植物，原生动物数量和生物量与TSIc呈高度一致性。作者认为,对湖泊进行营养状态评价时,既要选准评价因子,又要对水化学参数和生物参数进行综合评价。     

Prediction of complete bioremediation periods for PAH soil pollutants in different physical states by mechanistic models

Mass-transfer models and biodegradation models were developed for three theoretical physical states of polycyclic aromatic hydrocarbons (PAHs) in soil. These mechanistic models were used to calculate the treatment periods necessary for complete removal of the PAH pollutants from the soil under batch conditions. Results indicate that the bioremediation of PAHs in such systems is mainly mass-transfer limited. The potential for bioremediation as a treatment technique for PAH contaminated soils is therefore mainly determined by the mass-transfer dynamics of PAHs. Under mass-transfer limited conditions simplified mathematical models, based on the assumption of a zero dissolved PAH concentrations, can be used to predict the period of time needed for complete bioremediation.     

Long-Term Ecosystem Dynamics in the Serengeti: Lessons for Conservation

Abstract:  Data from long-term ecological studies further understanding of ecosystem dynamics and can guide evidence-based management. In a quasi-natural experiment we examined long-term monitoring data on different components of the Serengeti-Mara Ecosystem to trace the effects of disturbances and thus to elucidate cause-and-effect connections between them. The long-term data illustrated the role of food limitation in population regulation in mammals, particularly in migratory wildebeest and nonmigratory buffalo. Predation limited populations of smaller resident ungulates and small carnivores. Abiotic events, such as droughts and floods, created disturbances that affected survivorship of ungulates and birds. Such disturbances showed feedbacks between biotic and abiotic realms. Interactions between elephants and their food allowed savanna and grassland communities to co-occur. With increased woodland vegetation, predators' capture of prey increased. Anthropogenic disturbances had direct (hunting) and indirect (transfer of disease to wildlife) effects. Slow and rapid changes and multiple ecosystem states became apparent only over several decades and involved events at different spatial scales. Conservation efforts should accommodate both infrequent and unpredictable events and long-term trends. Management should plan on the time scale of those events and should not aim to maintain the status quo. Systems can be self-regulating through food availability and predator-prey interactions; thus, culling may not be required. Ecosystems can occur in multiple states; thus, there may be no a priori need to maintain one natural state. Finally, conservation efforts outside protected areas must distinguish between natural change and direct human-induced change. Protected areas can act as ecological baselines in which human-induced change is kept to a minimum     

Sperm swimming speed and energetics vary with sperm competition risk in bluegill (<Emphasis Type="Italic">Lepomis macrochirus</Emphasis>)

Under sperm competition, a males fertilization success depends largely on the ejaculate characteristics of competing males. Theoretical models predict that, in external fertilizers, increased risk of sperm competition should result in selection for increased sperm swimming speed. To test this prediction, we studied the behavior of sperm from parental and sneaker male bluegill (Lepomis macrochirus), a fish species characterized by high levels of cuckoldry due to alternative reproductive tactics of males (parentals and cuckolders). Because cuckolders (sneakers and satellites) always spawn in the presence of a parental male, but the reverse is not true, cuckolders experience the greater risk of sperm competition. We show here that the spermatozoa of sneakers have faster initial swimming speeds but shorter periods of motility than the sperm of parental males. Moreover, we show that sperm swimming speeds shortly after activation (when most fertilization occurs) are correlated with starting ATP levels in spermatozoa, suggesting that sperm competition has selected for higher energetic capacity in the sperm of sneakers. Thus, the higher energetic capacity and initial swimming speed of sneaker sperm may explain why, despite having fewer sperm per ejaculate than parentals, sneakers fertilize more eggs than parental males when they compete to fertilize a clutch of eggs.Communicated by L.W. Simmons     

Sperm characteristics associated with different male reproductive tactics in bluegills (Lepomis macrochirus)

We examined the availability and motility of sperm from parental and sneaker male bluegills (Lepomis macrochirus), a colonially nesting sunfish (Family Centrarchidae) with male parental care and a high incidence of cuckoldry by both sneaker and satellite males. We found no differences between sneakers and parentals in length and swimming speed of sperm, or percent and duration of sperm activity. In sneaker milt, however, sperm was almost 50% more concentrated than in parental milt (16.5×10⁶ vs 11.5×10⁶ sperm/μl of milt, respectively). Despite this difference in sperm concentration, stripped ejaculates from sneakers contained almost 400 million fewer sperm (only 32% as many sperm) than those from parentals due to their much smaller stripped ejaculate volumes (only about 19% that of parentals). Thus unless sneakers can compensate by releasing more sperm or gaining closer proximity to eggs at the time of spawning, they may be at a disadvantage with respect to sperm competition. We discuss these results in relation to models for the evolution of alternative reproductive behaviours in this species and suggest that the cuckolders may be making the best of a bad situation. Received: 18 February 2000 / Revised: 23 March 2000 / Accepted: 14 September 2000     

Male-male interference competition decreases spawning rate in the European bitterling (<Emphasis Type="Italic">Rhodeus sericeus</Emphasis>)

We investigated the consequences of male-male interference competition associated with alternative male mating tactics in a freshwater fish, the European bitterling (Rhodeus sericeus). Male bitterling defend territories around living mussels and attract females to lay their eggs in the gill cavities of mussels. We experimentally manipulated spawning-site abundance and male density at two spatial scales. We showed that the total number of eggs spawned by females was constrained by the number of mussels available for oviposition. The effect was mediated by behavioral interactions among competing males because of variation in the Operational Sex Ratio (OSR) in close proximity to a mussel and not by a direct limitation in mussel capacity to accommodate the eggs. Both total and local male densities affected spawning behavior, and interacted in their effect on female spawning rate. Territorial male aggression caused courtship interruptions that prolonged the time until successful spawning and increased with male density. However, territoriality broke down at the highest male density, with a consequent stabilizing effect on spawning rate.Communicated by J. Krause