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The article focuses on the paper "Air Quality Impacts of Climate Mitigation: U. K. Policy and Passenger Vehicle Choice," by Eric A. Mazzi and Hadi Dowlatabadi. This paper was awarded with the top paper award under the environmental policy category for the Best Paper Awards of the journal "Environmental Science & Technology." It analyzes the increasing number of diesel cars which unintentionally released higher amounts of ambient particular matter. The study found that this ambient air pollution is capable to create climate change issues with air quality. Furthermore, this study concludes that carbon tax will happen when policy makers will only focus on climate change.

Electricity generation through the burning of fossil fuels is one of the main contributors to the climate change problem. The use of renewable energy sources is a promising strategy to help mitigate this problem. This paper considers two forms of renewable energy: solar and biomass (algae) for power generation. The paper also accounts for the thermal storage of solar energy. A multiobjective optimization formulation is developed to reduce greenhouse gas emissions and cost in the electricity generation process. The model is based on a new superstructure that incorporates various design configurations and screens different thermal storage systems. A case study is presented to show the applicability of the proposed approach and how the economic and environmental objectives can be reconciled. [ABSTRACT FROM AUTHOR]

Increasing hydropower electricity production constitutes a unique opportunity to mitigate climate change impacts. However, hydropower electricity production also impacts aquatic and terrestrial biodiversity through freshwater habitat alteration, water quality degradation, and land use and land use change (LULUC). Today, no operational model exists that covers any of these cause-effect pathways within life cycle assessment (LCA). This paper contributes to the assessment of LULUC impacts of hydropower electricity production in Norway in LCA. We quantified the inundated land area associated with 107 hydropower reservoirs with remote sensing data and related it to yearly electricity production. Therewith, we calculated an average net land occupation of 0.027 m²⋅yr/kWh of Norwegian storage hydropower plants for the life cycle inventory. Further, we calculated an adjusted average land occupation of 0.007 m²⋅yr/kWh, accounting for an underestimation of water area in the performed maximum likelihood classification. The calculated land occupation values are the basis to support the development of methods for assessing the land occupation impacts of hydropower on biodiversity in LCA at a damage level. [ABSTRACT FROM AUTHOR]

Reducing food losses and waste is crucial to making our food system more efficient and sustainable. This is the first paper that quantifies the environmental impacts of food waste by distinguishing the various stages of the food value chain, 33 food categories that represent the whole food basket in Switzerland, and including food waste treatment. Environmental impacts are expressed in terms of climate change and biodiversity impacts due to water and land use. Climate change impacts of food waste are highest for fresh vegetables, due to the large amounts wasted, while the specific impact per kg is largest for beef. Biodiversity impacts are mainly caused by cocoa and coffee (16% of total) and by beef (12%). Food waste at the end of the food value chain (households and food services) causes almost 60% of the total climate impacts of food waste, because of the large quantities lost at this stage and the higher accumulated impacts per kg of product. The net environmental benefits from food waste treatment are only 5-10% of the impacts from production and supply of the wasted food. Thus, avoiding food waste should be a first-line priority, while optimizing the method of treatment is less relevant. [ABSTRACT FROM AUTHOR]

With the arising of global climate change and resource shortage, in recent years, increased attention has been paid to environmentally friendly materials. Trees are sustainable and renewable materials, which give us shelter and oxygen and remove carbon dioxide from the atmosphere. Trees are a primary resource that human society depends upon every day, for example, homes, heating, furniture, and aircraft. Wood from trees gives us paper, cardboard, and medical supplies, thus impacting our homes, school, work, and play. All of the above-mentioned applications have been well developed over the past thousands of years. However, trees and wood have much more to offer us as advanced materials, impacting emerging high-tech fields, such as bioengineering, flexible electronics, and clean energy. Wood naturally has a hierarchical structure, composed of well-oriented microfibers and tracheids for water, ion, and oxygen transportation during metabolism. At higher magnification, the walls of fiber cells have an interesting morphology--a distinctly mesoporous structure. Moreover, the walls of fiber cells are composed of thousands of fibers (or macrofibrils) oriented in a similar angle. Nanofibrils and nanocrystals can be further liberated from macrofibrils by mechanical, chemical, and enzymatic methods. The obtained nanocellulose has unique optical, mechanical, and barrier properties and is an excellent candidate for chemical modification and reconfiguration. Wood is naturally a composite material, comprised of cellulose, hemicellulose, and lignin. Wood is sustainable, earth abundant, strong, biodegradable, biocompatible, and chemically accessible for modification; more importantly, multiscale natural fibers from wood have unique optical properties applicable to different kinds of optoelectronics and photonic devices. Today, the materials derived from wood are ready to be explored for applications in new technology areas, such as electronics, biomedical devices, and energy. The goal of this study is to review the fundamental structures and chemistries of wood and wood-derived materials, which are essential for a wide range of existing and new enabling technologies. The scope of the review covers multiscale materials and assemblies of cellulose, hemicellulose, and lignin as well as other biomaterials derived from wood, in regard to their major emerging applications. Structure--properties-- application relationships will be investigated in detail. Understanding the fundamental properties of these structures is crucial for designing and manufacturing products for emerging applications. Today, a more holistic understanding of the interplay between the structure, chemistiy, and performance of wood and wood-derived materials is advancing historical applications of these materials. This new level of understanding also enables a myriad of new and exciting applications, which motivate this review. There are excellent reviews already on the classical topic of woody materials, and some recent reviews also cover new understanding of these materials as well as potential applications. This review will focus on the uniqueness of woody materials for three critical applications: green electronics, biological devices, and energy storage and bioenergy. [ABSTRACT FROM AUTHOR]

The mining of uranium has long been a controversial public issue, and a renewed debate has emerged on the potential for nuclear power to help mitigate against climate change. The central thesis of pro-nuclear advocates is the lower carbon intensity of nuclear energy compared to fossil fuels, although there remains very little detailed analysis of the true carbon costs of nuclear energy. In this paper, we compile and analyze a range of data on uranium mining and milling, including uranium resources as well as sustainability metrics such as energy and water consumption and carbon emissions with respect to uranium production—arguably the first time for modern projects. The extent of economically recoverable uranium resources is clearly linked to exploration, technology, and economics but also inextricably to environmental costs such as energy/water/chemicals consumption, greenhouse gas emissions, and social issues. Overall, the data clearly show the sensitivity of sustainability assessments to the ore grade of the uranium deposit being mined and that significant gaps remain in complete sustainability reporting and accounting. This paper is a case study of the energy, water, and carbon costs of uranium mining and milling within the context of the nuclear energy chain. [ABSTRACT FROM AUTHOR]

The U.S. National Assessment of the Potential Consequences of Climate Variability and Change was a federally coordinated nationwide effort that involved thousands of experts and stakeholders. To draw lessons from this effort, the 10 authors of this paper, half of whom were not involved in the Assessment, developed and administered an extensive survey, prepared a series of working papers, and conducted an invitational workshop in Washington, DC, on April 29, 2004. Considering all these sources, the authors conclude that the Assessment was largely successful in implementing its basic design of distributed stakeholder involvement and in achieving its basic objectives. Future assessments could be significantly improved if greater attention were devoted to developing a collective understanding of objectives, preparing guidance materials and providing training for assessment participants, developing a budgeting mechanism which would allow greater freedom in allocating resources across various assessment activities, and creating an environment in which assessments were part of an ongoing process. [ABSTRACT FROM AUTHOR]

Methane emissions from municipal landfills represent 3% of the total United States greenhouse gas emissions that contribute to climate change. These methane emissions can be released to the air or collected and flared. This landfill gas also has the potential to be used to generate electricity. In 1994, the Environmental Protection Agency (EPA) created the Landfill Methane Outreach Program, with the objective of promoting the development of landfill-gas- to-energy projects around the country. There are currently 2,300 active landfills in the United States. Although there are already 382 operational projects, there are many more landfills with the potential to use the gas. EPA has identified at least 630 candidate landfills for energy projects, and many more have still not been identified. The objective of this paper is to evaluate total private and social benefits of landfill-gas-to-energy projects, taking into consideration not only the costs of installing and maintaining the necessary equipment and the revenues obtained from selling the electricity but also a valuation of the greenhouse gas emissions that would be prevented and the emissions of criteria pollutants created by the electricity generating equipment. It also evaluates the break-even government subsidies that would be required to make such projects economically viable from private and social perspectives in comparison to current subsidies. it was found that the private breakeven price of electricity for these projects is lower than $0.04/kWh. Moreover, the optimum social subsidy was found to be less than $0.0085/ kWh, which is about 40% lower than the currently available federal tax break of $0.015/kWh. The method developed for this paper can be applied to other renewable energy technologies, to show their relative social costs and benefits. [ABSTRACT FROM AUTHOR]

The global warming and climate change problems have become more serious because of the high consumption of fossil fuels during the past century. Recently, biofuels have attracted interest as an option to reduce the extensive use of fossil fuels; particularly, biobutanol appears as an option to replace the petroleum-based fuels. However, the separation process to produce biobutanol requires a lot of energy and yields lots of waste heat at low temperature. Therefore, there is a need to propose options to reduce the required energy in the biobutanol separation process. Consequently, this paper presents an optimization approach for designing energy integrated biobutanol separation processes. The optimization incorporates attractive separation options such as ABE fermentation using different solvents as well as incorporating several options for waste heat recovery involving integrated heat exchanger networks, stream Rankine cycles, organic Rankine cycles, and absorption refrigeration cycles. The results show significant economic and environmental benefits for the simultaneous consideration of the optimization of the separation process with the waste heat recovery for the biobutanol separation process. [ABSTRACT FROM AUTHOR]

This paper aims to comprehensively distinguish among the merits of different vehicles using a common primary energy source. In this study, we consider compressed natural gas (CNG) use directly in conventional vehicles (CV) and hybrid electric vehicles (HEV), and natural gas-derived electricity (NG-e) use in plug-in battery electric vehicles (BEV). This study evaluates the incremental life cycle air emissions (climate change and human health) impacts and life cycle ownership costs of non-plug-in (CV and HEV) and plug-in light-duty vehicles. Replacing a gasoline CV with a CNG CV, or a CNG CV with a CNG HEV, can provide life cycle air emissions impact benefits without increasing ownership costs; however, the NG-e BEV will likely increase costs (90% confidence interval: $1000 to $31000 incremental cost per vehicle lifetime). Furthermore, eliminating HEV tailpipe emissions via plug-in vehicles has an insignificant incremental benefit, due to high uncertainties, with emissions cost benefits between -$1000 and $2000. Vehicle criteria air contaminants are a relatively minor contributor to life cycle air emissions impacts because of strict vehicle emissions standards. Therefore, policies should focus on adoption of plug-in vehicles in nonattainment regions, because CNG vehicles are likely more cost-effective at providing overall life cycle air emissions impact benefits. [ABSTRACT FROM AUTHOR]

Aerosols have been associated with large uncertainties in estimates of the radiation budget and cloud formation processes in the Arctic. This paper reports the results of a study of in situ measurements of hygroscopicity, fraction of volatile species, mixing state, and off-line morphological and elemental analysis of Aitken and accumulation mode particles in the Arctic (Ny-Ålesund, Svalbard) in May and September 2012. The accumulation mode particles were more abundant in May than in September. This difference was due to more air mass flow from lower latitude continental areas, weaker vertical mixing, and less wet scavenging in May than in September, which may have led to a higher amount of long-range transport aerosols entering the Arctic in the spring. The Aitken mode particles observed intermittently in May were produced by nucleation, absent significant external mixing, whereas the accumulation mode particles displayed significant external mixing. The occurrence of an external mixing state was observed more often in May than in September and more often in accumulation mode particles than in Aitken mode particles, and it was associated more with continental air masses (Siberian) than with other air masses. The external mixing of the accumulation mode particles in May may have been caused by multiple sources (i.e., long-range transport aerosols with aging and marine aerosols). These groups of externally mixed particles were subdivided into different mixing structures (internal mixtures of predominantly sulfates and volatile organics without nonvolatile species and internal mixtures of sulfates and nonvolatile components, such as sea salts, minerals, and soot). The variations in the mixing states and chemical species of the Arctic aerosols in terms of their sizes, air masses, and seasons suggest that the continuous size-dependent measurements observed in this study are useful for obtaining better estimates of the effects of these aerosols on climate change. [ABSTRACT FROM AUTHOR]

Dhaka had recently experienced rapid conversion of its motor vehicle fleet to run on compressed natural gas (CNG). This paper quantifies ex-post the air quality and climate benefits of the CNG conversion policy, including monetary valuations, through an impact pathway approach. Around 2045 (1665) avoided premature deaths in greater Dhaka (City Corporation) can be attributed to air quality improvements from the CNG conversion policy in 2010, resulting in a saving of around USD 400 million. Majority of these health benefits resulted from the conversion of high-emitting diesel vehicles. CNG conversion was clearly detrimental from climate change perspective using the changes in CO2 and CH4 only (CH4 emissions increased); however, after considering other global pollutants (especially black carbon), the climate impact was ambiguous. Uncertainty assessment using input distributions and Monte Carlo simulation along with a sensitivity analysis show that large uncertainties remain tor climate impacts. For our most likely estimate. there were some climate costs, valued at USD 17.7 million, which is an order of magnitude smaller than the air quality benefits. This indicates that such policies can and should be undertaken on the grounds of improving local air pollution alone and that precautions should be taken to reduce the potentially unintended increases in GHG emissions or other unintended effects. [ABSTRACT FROM AUTHOR]

The ability of hydropower to contribute to climate change mitigation is sometimes questioned, citing emissions of methane and carbon dioxide resulting from the degradation of biogenic carbon in hydropower reservoirs. These emissions are, however, not always addressed in life cycle assessment, leading to a bias in technology comparisons, and often misunderstood. The objective of this paper is to review and analyze the generation of greenhouse gas emissions from reservoirs for the purpose of technology assessment, relating established emission measurements to power generation. A literature review, data collection, and statistical analysis of methane and CO2 emissions are conducted. In a sample of 82 measurements, methane emissions per kWh hydropower generated are log-normally distributed, ranging from micrograms to 10s of kg. A multivariate regression analysis shows that the reservoir area per kWh electricity is the most important explanatory variable. Methane emissions flux per reservoir area are correlated with the natural net primary production of the area, the age of the power plant, and the inclusion of bubbling emissions in the measurement. Even together, these factors fail to explain most of the variation in the methane flux. The global average emissions from hydropower are estimated to be 85 gCO2/kWh and 3 gCH4/kWh, with a multiplicative uncertainty factor of 2. GHG emissions from hydropower can be largely avoided by ceasing to build hydropower plants with high land use per unit of electricity generated. [ABSTRACT FROM AUTHOR]

This paper presents a multiperiodoptimization approach to the cost-effective reduction of the negativeimpact caused by discharging industrial effluents into watersheds.The model considers all discharges and extractions, as well as thechemical reactions carried out in the watershed, while accountingfor the seasonal variability of the system through the year. The proposedmodel is based on a material flow analysis applied to a distributedtreatment system for industrial effluents in a macroscopic water system.The problem is formulated as a multiobjective optimization model withthe objectives of simultaneously minimizing the pollutant concentrationsin the final catchment areas and the total annual cost of the waste-treatmentunits. The model selects the place to locate the treatment units andthe type of treatment technology, as well as the industrial effluentstreated in each period of the year, to satisfy the environmental regulations.Two case studies are presented to show the applicability of the proposedoptimization approach: one is the Bahr El-Baqar drain in Egypt andthe other one is the Balsas watershed in Mexico. [ABSTRACT FROM AUTHOR]

Coal-fired power plants account for nearly 50% of U.S. electricity supply and about a third of U.S. emissions of CO2, the major greenhouse gas (GHG) associated with global climate change. Thermal power plants also account for 39% of all freshwater withdrawals in the U.S. To reduce GHG emissions from coal-fired plants, postcombustion carbon capture and storage (CCS) systems are receiving considerable attention. Current commercial amine-based capture systems require water for cooling and other operations that add to power plant water requirements. This paper characterizes and quantifies water use at coal-burning power plants with and without CCS and investigates key parameters that influence water consumption. Analytical models are presented to quantify water use for major unit operations. Case study results show that, for power plants with conventional wet cooling towers, approximately 80% of total plant water withdrawals and 86% of plant water consumption is for cooling. The addition of an amine-based CCS system would approximately double the consumptive water use of the plant. Replacing wet towers with air-cooled condensers for dry cooling would reduce plant water use by about 80% (without CCS) to about 40% (with CCS). However, the cooling system capital cost would approximately triple, although costs are highly dependent on site-specific characteristics. The potential for water use reductions with CCS is explored via sensitivity analyses of plant efficiency and other key design parameters that affect water resource management for the electric power industry. [ABSTRACT FROM AUTHOR]

The global climate problem becomes tractable if CO2 emissions from coal use are phased out rapidly and emissions from unconventional fossil fuels (e.g., oil shale and tar sands) are prohibited. This paper outlines technology options for phasing out coal emissions in the United States by ∼2030. We focus on coal for physical and practical reasons and on the U.S. because it is most responsible for accumulated fossil fuel CO2 in the atmosphere today, specifically targeting electricity production, which is the primary use of coal While we recognize that coal emissions must be phased out globally, we believe U.S. leadership is essential. A major challenge for reducing U.S. emissions is that coal provides the largest proportion of base loud power, i.e., power satisfying minimum electricity demand. Because this demand is relatively constant and coal has a high carbon intensity, utility carbon emissions are largely due to coal. The current U.S. electric grid incorporates little renewable power, most of which is not base load power. However, this can readily be changed within the next 2-3 decades. Eliminating coal emissions also requires improved efficiency, a "smart grid", additional energy storage, and advanced nuclear power. Any further coal usage must be accompanied by carbon capture and storage (CCS). We suggest that near-term emphasis should be on efficiency measures and substitution of coal-fired power by renewables and third- generation nuclear plants, since these technologies have been successfully demonstrated at the relevant (commercial( scale. Beyond 2030, these measures can be supplemented by CCS at power plants and, unneeded, successfully demonstrated fourth-generation reactors. We conclude that U.S. coal emissions could be phased out by 2030 using existing technologies or ones that could be commercially competitive with coal within about a decade. Elimination of fossil fuel subsidies and a substantial rising price on carbon emissions are the root requirements for a clean, emissions-free future. [ABSTRACT FROM AUTHOR]

Carbon emissions from industry are dominated by production of goods in steel, cement, plastic, paper, and aluminum. Demand for these materials is anticipated to double at least by 2050, by which time global carbon emissions must be reduced by at least 50%. To evaluate the challenge of meeting this target, the global flows of these materials and their associated emissions are projected to 2050 under five technical scenarios. A reference scenario includes all existing and emerging efficiency measures but cannot provide sufficient reduction. The application of carbon sequestration to primary production proves to be sufficient only for cement. The emissions target can always be met by reducing demand, for instance through product life extension, material substitution, or "light-weighting". Reusing components shows significant potential particularly within construction. Radical process innovation may also be possible. The results show that the first two strategies, based on increasing primary production, cannot achieve the required emissions reductions, so should be balanced by the vigorous pursuit of material efficiency to allow provision of increased material services with reduced primary production. [ABSTRACT FROM AUTHOR]

In contrast to conventional carbon capture systems for power plants and other large point sources, the system described in this paper captures CO2 directly from ambient air. This has the advantages that emissions from diffuse sources and past emissions may be captured. The objective of this research is to determine the feasibility of a NaOH spray-based contactor for use in an air capture system by estimating the cost and energy requirements per unit CO2 captured. A prototype system is constructed and tested to measure CO2 absorption, energy use, and evaporative water loss and compared with theoretical predictions. A numerical model of drop collision and coalescence is used to estimate operating parameters for a full- scale system, and the cost of operating the system per unit CO2 captured is estimated. The analysis indicates that CO2 capture from air for climate change mitigation is technically feasible using off-the-shelf technology. Drop coalescence significantly decreases the CO2 absorption efficiency; however, fan and pump energy requirements are manageable. Water loss is significant (20 mol H2O/mol CO2 at 15 °C and 65% RH) but can be lowered by appropriately designing and operating the system. The cost of CO2 capture using NaOH spray (excluding solution recovery and CO2 sequestration, which may be comparable) in the full-scale system is 96 $/ton-CO2 in the base case, and ranges from 53 to 127 $/ton-CO2 under alternate operating parameters and assumptions regarding capital costs and mass transfer rate. The low end of the cost range is reached by a spray with 50 µm mean drop diameter, which is achievable with commercially available spray nozzles. [ABSTRACT FROM AUTHOR]

The article focuses on two papers, which appeared within the issue of "Environmental Science and Technology," about the planet's changing climate and diminishing resources. James Mihelcic and Julie Zimmerman describe scientific and technological tools in developing countries that have proven useful in implementing sustainable living. They argue that indigenous knowledge needs to be included in global conversations on sustainability. On the second paper, Mihelcic and Zimmerman discuss such successful instruments.

This article presents information about Stephen McIntyre, a semiretired businessman. McIntyre's attack on one climate-change study, known as the hockey stick, got him featured on the front-page of the February 14, 2005, issue of the Wall Street Journal. In June, U.S. Representative Joe Barton demanded that prominent researchers turn over the raw data from the hockey-stick analysis. Researchers criticized the journal and Barton. However scientists look at these events, the success of climate change skeptic McIntyre hints at why the findings of the Intergovernmental Panel on Climate Change report and other mainstream, peer-reviewed global climate studies have failed to persuade the U.S. Congress that action is needed to curb greenhouse gas emissions. McIntyre began his career in climate studies in 2003 when he published a paper in Energy & Environment. McIntyre outlined what they called serious errors in the hockey-stick analysis. McIntyre was flown to Washington, D.C., to brief U.S. business leaders and senators. After this fleeting brush with fame, McIntyre retreated to Canada and began a more aggressive attack on the hockey stick. He launched a blog to attract attention to his research. In early January of 2005, he finally had a paper accepted into a real science journal Geophysical Research Letters. Within weeks of publishing his first study, McIntyre was profiled on the front page of the Wall Street Journal.

An International Year of Chemistry legacy project to highlight connections between chemistry and sustainability is described. The project consists of nine critically reviewed, interactive, Web-based modules (digital learning objects) at the Web site explainingclimatechange.com to help students visualize and understand the underlying science of climate change while making connections to chemistry curriculum. The target audiences are (a) teachers and students at the secondary and first-year tertiary levels and (b) chemistry professionals. This communication summarizes one of the invited papers to the ConfChem online conference A Virtual Colloquium to Sustain and Celebrate IYC 2011 Initiatives in Global Chemical Education held from May 18 to June 28, 2012 and jointly hosted by the ACS DivCHED Committee on Computers in Chemical Education and the IUPAC Committee on Chemistry Education. [ABSTRACT FROM AUTHOR]