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991.
If hydrogen (H2) is to significantly reduce greenhouse gas emissions and oil use, it needs to displace conventional transport fuels and be produced in ways that do not generate significant greenhouse gas emissions. This paper analyses alternative ways H2 can be produced, transported and used to achieve these goals. Several H2 scenarios are developed and compared to each other. In addition, other technology options to achieve these goals are analyzed. A full fuel cycle analysis is used to compare the energy use and carbon (C) emissions of different fuel and vehicle strategies. Fuel and vehicle costs are presented as well as cost-effectiveness estimates. Lowest hydrogen fuel costs are achieved using fossil fuels with carbon capture and storage. The fuel supply cost for a H2 fuel cell car would be close to those for an advanced gasoline car, once a large-scale supply system has been established. Biomass, wind, nuclear and solar sources are estimated to be considerably more expensive. However fuel cells cost much more than combustion engines. When vehicle costs are considered, climate policy incentives are probably insufficient to achieve a switch to H2. The carbon dioxide (CO2) mitigation cost would amount to several hundred US$ per ton of CO2. Energy security goals and the eventual need to stabilize greenhouse gas concentrations could be sufficient. Nonetheless, substantial development of related technologies, such as C capture and storage will be needed. Significant H2 use will also require substantial market intervention during a transition period when there are too few vehicles to motivate widely available H2 refueling.
Dolf GielenEmail:
  相似文献   
992.
The ionization potential of one-electron ions can be calculated from a well-known simple equation, but no such equation has been available for calculating the ionization potential of multi-electron ions. I report here an equation that accurately gives the ionization potential of helium-like (i.e., two-electron) ions as a function of the atomic number, the relative difference from experimental values being below 1% for all ions for which reliable experimental data were found (Z = 3–29). The equation also predicts the stability of the negative hydrogen ion (the hydride ion), H, although with twice too large a value for the ionization potential.  相似文献   
993.
Persistent organic pollutants control strategy in China   总被引:1,自引:0,他引:1  
The development of Persistent Organic Pollutants(POPs) control policy in China in the context of international concerns on POPs was reviewed. The aspects of the Chinese POPs control strategies were analyzed, and compared with those of developed counterparts(e.g. US, EU, Japan). Currently, while the legal framework on POPs management, which complies with intemational guidelines has been established, it should be improved in the areas of special POPs management, risk assessment, the precautionary principle, lifecycle management and technical support capacity. The analysis of Chinese POPs policy and suggestions for strengthening the sciencebased decision making capacity are not only useful for Chinese decision-makers, but also a case study for developing wodd and make a great contribution for the global elimination of POPs to make a toxic-free future.  相似文献   
994.
负载铁生物炭(FeBC)已证实对溶液体系和雄黄矿高砷(As)尾渣中的无机As具有极为显著的吸附钝化效能,但其对土壤-水稻系统中As的溶出特性和生物有效性的影响尚为空白.为此,本研究系统探析了FeBC处理对水稻根际As溶出特性、根表铁膜As持留-释放模式转化和As向水稻体内各器官转运积累的影响与发生机制.结果表明,FeBC处理条件下的水稻根际pH普遍高于对照(CK),而氧化还原电位(Eh)则低于CK;FeBC处理所导致的根际Eh下降几乎同步使根际孔隙水As、Fe浓度自分蘖期后均随FeBC比例的增加而升高,且孔隙水As、Fe浓度具有显著正相关性(p0.01).成熟期内根表铁膜Fe、As含量均随FeBC比例的增加而升高,这一点可由微区X射线荧光(μ-XRF)所显示的2%FeBC处理中水稻根系表面Fe、As浓度均显著高于CK得到印证,而这一特点导致FeBC处理下的白根和糙米As含量显著升高(p0.05).以上结果表明,FeBC能有效提高水稻根表铁膜形成量及其对As的持留,但超过特定阈值的铁膜浓度(20~25 mg·g~(-1))对As的大量富集却可成为根系对As的吸收源,促进As向根系内的转运,并导致稻米As积累量升高.由此可见,含Fe钝化剂对水稻根际As生物有效性的影响具有可变性,其应用风险和产生机制值得引起高度关注.  相似文献   
995.
Enhancing agro-ecosystem sustainability raises difficult challenges for environmental policy: it requires both increasing knowledge on these complex systems to design effective solutions and coordinating stakeholders with diverging interests. However, most existing environmental policies consider ecosystems’ desirable properties as given, leading ecosystem managers to favor “turnkey” solutions. How could public policy better support local collective initiatives aiming at reconciling agriculture and the environment? This paper presents an empirical case study from western France, in which a partnership between an agricultural cooperative and an ecological research center resulted in a collective design initiative. We conceptually model this initiative drawing upon recent design theories and Georgescu-Roegen’s ‘fund-flow’ model, defining ‘ecological funds’ as the starting point of a collective design process. The results highlight the importance of developing policy instruments that can better support local innovation processes through greater democratization. Adopting a design approach to sustainable agricultural landscape management could be particularly fruitful in situations where collective action is necessary but where there is no common good recognized as such, and no existing community identified.  相似文献   
996.
The outcome of recent international climate negotiations suggests we are headed toward a more fragmented carbon market, with multiple emission trading and offset programs operating in parallel. To effectively harmonize and link across programs, it will be important to ensure that across offset programs and protocols that a “ton is a ton”. In this article, we consider how sample offsets projects in the U.S. carbon market are treated across protocols from five programs: the Clean Development Mechanism, Climate Action Reserve, Chicago Climate Exchange, Regional Greenhouse Gas Initiative, and the U.S. EPA's former program, Climate Leaders. We find that differences among protocols for landfill methane, manure management, and afforestation/reforestation project types in accounting boundary definitions, baseline setting methods, measurement rules, emission factors, and discounts lead to differences in offsets credited that are often significant (e.g. greater than 50%). We suggest opportunities for modification and harmonization of protocols that can improve offset quality and credibility and enhance prospects for future linking of trading units and systems.  相似文献   
997.
This paper aims to assess the renewable energy capacity of Turkey in order to consider main priorities in the energy policy of Turkey. In this paper, renewable energy potential and regulatory conditions are discussed in Turkey in comparison with European Union. The results of the study implemented within the framework of EnviroGRIDS project indicated a promising yet very susceptible future for the implementation of renewable energy power plants in Turkey. The forecasts have shown that the solar power potential utilization is becoming more significant after 2020. The projections for 2050 indicate that electricity consumption from small and medium renewable energy sources including solar and wind will constitute 15% of the total, whereas the solar thermal will constitute around 16%. Geothermal and other renewables will remain around 3%. According to the high demand scenario, in 2050 the share of hydropower in overall electricity generation will be 12%, followed by solar power at 7% and wind power at 3%. Additionally, renewable energy policy and regulations in Turkey and in EU are overviewed in this study. On the contrary to EU, the constant feed-in tariff amount does not consider capital investments of specific energy sources in Turkey that brings disadvantage to the implementation. However, new regulations published and currently applied should be accepted as milestones in acquisition period of Turkey in EU.  相似文献   
998.
Despite increasing interest in learning from Indigenous communities, efforts to involve Indigenous knowledge in environmental policy-making are often fraught with contestations over knowledge, values, and interests. Using the co-production of knowledge and social order (Jasanoff, 2004), this case study seeks to understand how some Indigenous communities are engaging in science-policy negotiations by linking traditional ecological knowledge (TEK), western science, and other knowledge systems. The analysis follows twenty years of Indigenous forest management negotiations between the Xáxli’p community and the Ministry of Forests in British Columbia (B.C.), Canada, which resulted in the Xáxli’p Community Forest (XCF). The XCF is an eco-cultural restoration initiative that established an exclusive forest tenure for Xáxli’p over the majority of their aboriginal territory—a political shift that was co-produced with new articulations of Xáxli’p knowledge. This research seeks to understand knowledge co-production with Indigenous communities, and suggests that existing knowledge integration concepts are insufficient to address ongoing challenges with power asymmetries and Indigenous knowledge. Rather, this work proposes interpreting XCF knowledge production strategies through the framework of “Indigenous articulations,” where Indigenous peoples self-determine representations of their identities and interests in a contemporary socio-political context. This work has broader implications for considering how Indigenous knowledge is shaping science-policy negotiations, and vice versa.  相似文献   
999.
There has been much debate about the assessment process of the Intergovernmental Panel on Climate Change (IPCC). Yet two of the most fundamental challenges that directly threaten the ability of the IPCC to fulfill its mandate have been largely neglected so far. Firstly, the magnitude and rapid expansion of the climate change literature makes it increasingly impossible for the IPCC to conduct comprehensive and transparent assessments without major innovations in assessment practices and tools. Secondly, the structure, organization and scientific practices across the social sciences and humanities prohibit systematic learning on climate change solutions and increasingly limit the policy-relevance of IPCC assessments. We highlight the need for responses along three avenues to prepare the IPCC for continued success in the future: 1) IPCC assessments must make better use of big-data methods and available computational power to assess the growing body of literature and ensure comprehensiveness; 2) systematic review practices need to be enshrined into IPCC procedures to ensure adequate focus and transparency in its assessments; 3) a synthetic research culture needs to be established in the social sciences and humanities in order to foster knowledge accumulation and learning on climate solutions in the future. As policymakers become more interested in understanding solutions, the future prospects of global environmental assessment enterprises will depend heavily on a successful transformation within the social sciences and humanities towards systematic knowledge generation. This article is part of a special issue on solution-oriented Global Environmental Assessments.  相似文献   
1000.
Natura 2000, the nature network based on the European Bird and Habitat Directives, is explicitly grounded on ecological science. To acquire a permit under the Dutch Nature Conservation Act, an appropriate assessment of significant effects must be conducted based on the best available scientific knowledge. In this way the scientific and policy world are directly linked. This article focuses on ‘significant effect’ as a boundary object to analyse how science–policy interactions shape the meaning and assessment of significant effect and how these interpretations influence the decision-making process. To this end, two conflicts over significant effect are investigated: the conflict over the 2006-spring permit for the mussel seed fishery, and the 2011 permit for the planned World Championship powerboat races. In both cases nature organisations started a court process against the government-granted permits in protest to the “no significant effect” claim, stating that there was insufficient certainty for this conclusion. These conflicts are approached as controversies between discourse coalitions with different interpretations of the ecological knowledge. We show how significant effect became a focal point in the controversies, limiting the debate to ecological arguments and science-based expertise, but also creating options for parties to advance their protest by articulating uncertainties. Only uncertainty of incomplete knowledge was explicitly addressed, excluding ambiguity of values and unpredictability of the actual ecosystem. We suggest that acknowledging the value aspect in disputes on significant effect would leave more space for effective solutions of the problems under debate.  相似文献   
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