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Wildfires are becoming more frequent due to the global climate change. Large amounts of greenhouse gases emitted by wildfires can lead to increases in extreme climate events. Accurately estimating the greenhouse gas carbon dioxide (CO2) emissions from wildfires is important for mitigation of climate change. In this paper, we develop a novel method to estimate wildfire CO2 emissions from the relationship between local CO2 emissions and XCO2 anomalies. Our method uses the WRF-Chem assimilation system from OCO-2 XCO2 retrievals which coupled with Data Assimilation Research Testbed (DART). To validate our results, we conducted three experiments evaluating the wildfire CO2 emissions over the conterminous United States. The four-month average wildfire emissions from July to October in 2015∼2018 were estimated at 4.408 Tg C, 1.784 Tg C, 1.514 Tg C and 2.873 Tg C, respectively. Compared to the average of established inventories CT2019B, FINNv1.5 and GFASv1.2 fire emissions, our estimates fall within one standard deviation, except for 2017 due to lacking of OCO-2 XCO2 retrievals. These results suggest that the regional carbon assimilation system, such as WRF-Chem/DART, using OCO-2 XCO2 retrievals has a great potential for accurately tracking regional wildfire emissions. [ABSTRACT FROM AUTHOR]

The article reports on the proposal publishing companies to becoming entirely carbon neutral and reduce its carbon emission in the U.S. Hearst Corp. plans to consider the implications for their magazines after the calculation on the amount of carbon dioxide emissions produced in the process of publishing. On the other hand, Time Inc. announced that it had asked their paper suppliers to reduce their greenhouse gas emissions by 20 percent by 2012.

Objective: This paper examines the relationship between obesity and greenhouse gas (GHG) emissions while accounting for the environmental impact of growth in transportation output and in crop and animal farming. Study Design: The study makes use of US state-level longitudinal data over the 1997--2011 period. Methods: Random effects and fixed effects estimators are employed within a multiple regression analysis framework. Results: After controlling for other sources of emissions, there is evidence that the effect of transportation output on CO2 emissions worsens at obesity rates exceeding 33.7% and the effect on N2O emissions worsens at obesity rates exceeding 22.5%. In addition, the impact of crop and animal farming on N2O emissions worsens at obesity rates exceeding 20.2%. Conclusion: This paper provides significant and new insight about the causal link between obesity and environmental emissions and highlights the importance of addressing the obesity epidemic on public health and environmental grounds. Thus, mitigating GHG emissions connected to obesity requires joint effort between policymakers, public health officials, and parties from concerned economic sectors in pursuing remedial actions to reverse the current obesity trend. Various policy measures are discussed. [ABSTRACT FROM AUTHOR]

The U.S. Clean Power Plan stipulates a state-specific performance-based CO2 emission standard, delegating states with considerable flexibility for using either a tradable performance-based or a mass-based permit program. This paper analyzes these two standards under imperfect competitive. We limit our attention to (1) short-run analyses and (2) a situation in which all states are subject to the same type of standard. We show that while the cross-subsidy inherent in the performance- based standard might effectively reduce power prices, it could also inflate energy consumption. A dominant firm with a relatively clean endowment under the performance-based standard would be able to manipulate the electricity market as well as to elevate permit prices, which might worsen market outcomes compared to its mass-based counterpart. On the other hand, the "cross-subsidy" could be the dominant force leading to a higher social welfare if the leader has a relatively dirty endowment. [ABSTRACT FROM AUTHOR]

Abstract: Proper understanding of the determinants of household CO2 emissions is essential for a shift to sustainable lifestyles. This paper explores the impacts of date of birth and income on household CO2 emissions in France and in the USA. Direct CO2 emissions of French and American households are computed from consumer budget surveys, over the 1980–2000 time period. Age Period Cohort estimators are used to isolate the generational effect on CO2 emissions — i.e. the specific effect of date of birth, independent of the age, the year and other control variables. The paper shows that French 1935–55 cohorts have a stronger tendency to emit CO2 than their predecessors and followers. The generational effect is explained by the fact that over their lifespan, French baby boomers are better off than other generations and live in energy and carbon inefficient dwellings. In the USA, the absence of a generational effect on CO2 emissions can be explained by the fact that intergenerational income inequalities are weaker than in France. Persistence of the generational effect once income and housing type is controlled for in France can be explained by the difficulty for French 1935–55 cohorts to adapt to sober energy consumption patterns. [Copyright &y& Elsevier]

This paper studies the relationship between income inequality and carbon emissions in the United States between 1929 and 2019. We contribute to the literature by studying if and how the relationship has varied over time. To this end we estimate a band spectrum regression model and a smooth-varying coefficients model. Our results show that higher inequality was associated with lower emissions during the early part of the sample and higher emissions towards the end of the sample. • Whether the level of inequality affects carbon dioxide emssions is unclear. • We test the association between income inequalty and carbon dioxide emissions. • We find that the relationship varies over time. • Changes in consumption patterns may partially explain the time varying effects. [ABSTRACT FROM AUTHOR]

Introduction: Over the past 20 years, there has been a tripling in the consumption of small cigars and cigarillos, with further increases expected because cigar products are not subject to Food and Drug Administration regulations. Acute toxin exposure from cigar smoking is difficult to assess because unlike cigarettes, cigars vary widely in size, design, composition, and in the smoking behavior of their consumers. For example, a recent practice among urban youth is to remove the paper liner (i.e., “freaking”) of a small cigar in the belief that it is this paper liner that leads to addiction and cancer. Methods: We examined acute exposure (CO and nicotine boosts) and puffing behavior in 12 participants (10 men) who smoked (ad lib) their usual conventional cigarette, a Black & Mild cigar (B&M) and a B&M without the paper liner (i.e., “freaked” [B&Mf]). Results: All products (cigarettes, B&M, and B&Mf) significantly increased heart rate and CO with a trend for plasma nicotine. Nicotine boost was significantly higher after cigarette smoking than both B&M and B&Mf, while CO boost was significantly greater after B&M and B&Mf than cigarettes. The CO boost after B&M was larger than after B&Mf. Conclusions: These findings suggest that small cigar smoking is associated with smoke inhalation that leads to significant exposure to nicotine, CO, and presumably other components of tobacco smoke and that removing the inner liner does not substantially reduce toxin exposure. [ABSTRACT FROM PUBLISHER]

Purpose – The purpose of this paper is to forecast the performance and adoption of residential energy management technology (REMT).Design/methodology/approach – The paper integrates scenarios, analogy and Bass diffusion model.Findings – Four different scenarios were identified. Bass curve parameters were extracted through many different existing devices, and then fit into each scenario subjectively to produce four different kinds of diffusion curves.Originality/value – The approach and the model provide decision and policy makers to evaluate how they should position new energy management innovations based on the desired type of diffusion. [ABSTRACT FROM AUTHOR]

Abstract: Optimization of combined cooling, heating, and power (CCHP) systems operation commonly focuses only on energy cost. Different algorithms have been developed to attain optimal utilization of CCHP units by minimizing the energy cost in CCHP systems operation. However, other outcomes resulting from CCHP operation such as primary energy consumption and emission of pollutants should also be considered during CCHP systems evaluation as one would expect these outcomes can be subject to regulation. This paper presents an optimization of the operation of CCHP systems for different climate conditions based on operational cost, primary energy consumption (PEC), and carbon dioxide emissions (CDE) using an optimal energy dispatch algorithm. The results for the selected cities demonstrate that in general there is not a common trend among the three optimization modes presented in this paper since optimizing one parameter may reduce or increase the other two parameters. The only cities that show reduction of PEC while also reducing the CDE are Columbus, MS; Minneapolis, MN; and Miami, FL. For these cities the operational cost always increases when compared to the reference case consisting of using a vapor/compression cycle for cooling and natural gas for heating. On the other hand, for San Francisco and Boston, CCHP systems increase the CDE. In general, if CCHP systems increase the cost of operation, as long as energy savings and reduction of emissions are guaranteed, the implementation of these systems should be considered. [Copyright &y& Elsevier]

Abstract As carbon dioxide and other greenhouse gases accumulate in the atmosphere and contribute to rising global temperatures, it is important to examine how derivative changes in climate may affect natural and managed ecosystems. In this series of papers, we study the impacts of climate change on agriculture, water resources and natural ecosystems in the conterminous United States using twelve scenarios derived from General Circulation Model (GCM) projections to drive biophysical impact models. These scenarios are described in this paper. The scenarios are first put into the context of recent work on climate-change by the IPCC for the 21st century and span two levels of global-mean temperature change and three sets of spatial patterns of change derived from GCM results. In addition, the effect of either the presence or absence of a CO2 fertilization effect on vegetation is examined by using two levels of atmospheric CO2 concentration as a proxy variable. Results from three GCM experiments were used to produce different regional patterns of climate change. The three regional patterns for the conterminous United States range from: an increase in temperature above the global-mean level along with a significant decline in precipitation; temperature increases in line with the global-mean with an average increase in precipitation; and, with a sulfate aerosol effect added to in the same model, temperature increases that are lower than the global-mean. The resulting set of scenarios span a wide range of potential climate changes and allows examination of the relative importance of global-mean temperature change, regional climate patterns, aerosol cooling, and CO2 fertilization effects. [ABSTRACT FROM AUTHOR]

Abstract As carbon dioxide and other greenhouse gasses accumulate in the atmosphere and contribute to rising global temperatures, it is important to examine how a changing climate may affect natural and managed ecosystems. In this series of papers, we study the impacts of climate change on agriculture, water resources and natural ecosystems in the General Circulation Model (GCM)-derived climate change projections, described in Part 1, to drive the crop production and water resource models EPIC (Erosion Productivity Impact Calculator) and HUMUS (Hydrologic Unit Model of the United States). These models are described and validated in this paper using historical crop yields and streamflow data in the conterminous United States in order to establish their ability to accurately simulate historical crop and water conditions and their capability to simulate crop and water response to the extreme climate conditions predicted by GCMs. EPIC simulated grain and forage crop yields are compared with historical crop yields from the US Department of Agriculture (USDA) and with yields from agricultural experiments. EPIC crop yields correspond more closely with USDA historical county yields than with the higher yields from intensively managed agricultural experiments. The HUMUS model was validated by comparing the simulated water yield from each hydrologic basin with estimates of natural streamflow made by the US Geological Survey. This comparison shows that the model is able to reproduce significant observed relationships and capture major trends in water resources timing and distribution across the country. [ABSTRACT FROM AUTHOR]

The aim of this study was to examine the effects of elevated carbon dioxide [CO2] and ozone [O3] and their interaction on wood chemistry and anatomy of five clones of 3-year-old trembling aspen (Populus tremuloides Michx.). Wood chemistry was studied also on paper birch (Betula papyrifera Marsh.) and sugar maple (Acer saccharum Marsh.) seedling-origin saplings of the same age. Material for the study was collected from the Aspen Free-Air CO2 Enrichment (FACE) experiment in Rhinelander, WI, USA, where the saplings had been exposed to four treatments: control (C; ambient CO2, ambient O3), elevated CO2 (560ppm during daylight hours), elevated O3 (1.5 × ambient during daylight hours) and their combination (CO2 + O3) for three growing seasons (1998–2000). Wood chemistry responses to the elevated CO2 and O3 treatments differed between species. Aspen was most responsive, while maple was the least responsive of the three tree species. Aspen genotype affected the responses of wood chemistry and, to some extent, wood structure to the treatments. The lignin concentration increased under elevated O3 in four clones of aspen and in birch. However, elevated CO2 ameliorated the effect. In two aspen clones, nitrogen in wood samples decreased under combined exposure to CO2 and O2. Soluble sugar concentration in one aspen clone and starch concentration in two clones were increased by elevated CO2. In aspen wood, α-cellulose concentration changed under elevated CO2, decreasing under ambient 03 and slightly increasing under elevated O3. Hemicellulose concentration in birch was decreased by elevated CO2 and increased by elevated O3. In aspen, elevated O3 induced statistically significant reductions in distance from the pith to the bark and vessel lumen diameter, as well as increased wall thickness and wall percentage, and in one clone, decreased fibre lumen diameter. Our results show that juvenile wood properties of broadleaves, depending on species and genotype, were altered by atmospheric gas concentrations predicted for the year 2050 and that CO2 ameliorates some adverse effects of elevated O3 on wood chemistry. [ABSTRACT FROM AUTHOR]

This paper based on quantile stochastic frontier framework constructs quantile eco-efficiency measures. Using the estimates from the quantile stochastic frontier, the eco-performance of the U.S. states for nitrogen oxides (NO X), carbon dioxide (CO 2), and sulfur dioxide (SO 2) emissions is evaluated. A decoupling analysis involving the evaluation of the nonsynchronous change among states' economic output and environmental degradation levels is also performed. The findings suggest that U.S. states have followed a decoupling process among their GDP and emission levels over the period 1990–2017. In addition, a quantile eco-productivity change estimator is presented alongside with its main components (i.e. quantile eco-technical change and quantile eco-efficiency change). Our findings suggest that over the examined period states' eco-productivity levels have been improved driven both from their eco-technical and eco-efficiency change levels. • We examine regional eco-efficiency across the US states. • We examine regional eco-productivity across the US states. • We employ a quantile stochastic frontier analysis. • We employ a decoupling analysis among U.S. states' GDP and emissions levels. • We find that eco-productivity levels was driven by eco-technical change levels. [ABSTRACT FROM AUTHOR]

In this paper, we analyze how carbon emissions affect the selection of transportation modes and social welfare by using a two-stage Stackelberg gaming model. Based on this model, the government’s optimal carbon-emission tax scheme and the company’s optimal transportation mode and production decisions are explored. We find that: 1) whether or not the transport carbon-emission tax can increase social welfare depends on the relationships among the social cost of carbon (SCC), the transportation mode shifting threshold (TMST), and the biggest carbon-emission tax that a company can afford (BCRA); 2) a greater SCC implies a higher probability of improving social welfare via imposing transportation carbon-emission tax; and 3) a smaller TMST or BCRA yields a higher probability of improving social welfare when a carbon-emission tax is imposed. Further study shows that imposing a carbon-emission tax on the product with a higher production cost, a bigger product volume, or a bigger product density can increase the probability of improving social welfare. [ABSTRACT FROM PUBLISHER]

This paper examines the asymmetry of changes in CO 2 emissions over business cycle recessions and expansions using yearly data from 1949 and monthly data from 1973 for the United States (US). In addition, decomposition analysis is applied to investigate the relative roles of various proximate contributing factors to observed changes in total and per capita CO 2 emissions and emissions intensity, over business cycle phases. The results suggest, inter alia , that aggregate emissions and emissions intensity reduce much faster in contractions than they increase in expansions. In addition, unlike the three previous expansions, in the most recent post-GFC US expansion, emissions per capita have continued to decline, and at a rate very similar to the rate of reduction in preceding contractions. This suggests the real possibility that the most recent contraction may have had an ongoing impact on the path of per capita emissions well beyond the immediate impact experienced during the contraction itself. [ABSTRACT FROM AUTHOR]

Abstract: There is mounting concern about the buildup of carbon dioxide (CO2) and other so-called greenhouse gases in the atmosphere. In general, bioethanol production requires minimal fossil fuel input in the conversion step, and ethanol is considered a promising alternative fuel to petroleum-derived products. It is anticipated that ethanol production with second-generation biomass, i.e. lignocellulosic materials, will be possible on a large scale in the near future. Latest efforts have been focused on overcoming technical challenges in bioconversion, particularly pretreatment, and finding the solutions required to implement biorefinery on a large scale. This paper introduces and reviews the current status of research, and of the ethanol industry in the U.S. In addition, other important concepts in biofuels, cellulosic ethanol, and biorefinery in general are reviewed, and the key technical issues in bioconversion of cellulosic ethanol, such as pretreatment and factors affecting bioconversion of biomass are also discussed. [Copyright &y& Elsevier]

Abstract: This paper investigates the challenge that U.S. aviation would face in meeting future Greenhouse Gas (GHG) reduction goals to mitigate global climate change via technological options. This investigation is done within a framework that considers aviation GHG emissions as a function of aviation growth, aircraft efficiency, operational efficiency, and life cycle GHG emissions of aviation fuels. The concept of life cycle GHG intensity (LGI) with units of grams carbon dioxide equivalent per payload distance traveled is used for this purpose as it can be decomposed into components that quantify improvements in aircraft design, operations, and alternative fuels. For example, the life cycle GHG intensity of U.S. aviation in 2005 was 1.37g CO2e/kgkm. If U.S. aviation is to meet the IATA 2050 goal of a 50% reduction in CO2 relative to a 2005 baseline while allowing for a 3.2% annual growth rate in payload–distance traveled, it will need to decrease to 0.22g CO2e/kgkm in 2050, an 84% reduction. The analysis framework that is developed in this manuscript was used to compare the improvements in life cycle GHG intensity that could accompany the use of advanced aircraft designs, operational improvements, and alternative fuels to those required on a fleet-wide basis to meet the future GHG reduction goals under varied aviation growth scenarios. The results indicate that the narrow body segment of the fleet could indeed meet ambitious goals of reducing GHG emissions by 50%, relative to 2005 levels, with a 3.2% annual growth rate; however, it would require relatively rapid adoption of innovative aircraft designs and the widespread use of alternative fuels with relatively low life cycle GHG emissions. [Copyright &y& Elsevier]

This paper explores methods for analyzing onboard mass emissions data and developing modal models on the basis of case study examples for nine selected nonroad construction vehicles. Data for these vehicles were obtained from the U.S. Environmental Protection Agency (EPA). Several modeling methods were explored, including stratification of the data into operating modes and supplementing the modal models with ordinary least-squares regression and multiple least-squares regression. The modal approach offers the advantages as conceptually the simplest, reducing the influence of autocorrelation in the model and providing substantial explanatory power. The normalized relationship between predicted mode-specific average emissions and exhaust flow is stable, similar, and consistent for all vehicles. For a given engine, the average emission rate can vary by more than a factor of two when comparing highest to lowest rates among different duty cycles. Some engines are common to different types of equipment, such as bulldozers and front-end loaders. For a given type of equipment, such as bulldozers, average and mass emission rates can vary by more than 50% depending on the duty cycle. Vehicle category-specific modal models are recommended on the basis of onboard second-by-second in-use activity and emissions data and for use in new modeling tools to estimate emissions produced by nonroad construction vehicles. [ABSTRACT FROM AUTHOR]

Natural gas comprises about a quarter of the United States' energy use. It is more environmentally friendly than oil and coal due to lower carbon dioxide (CO2) emissions per unit, less costly per unit of energy and more readily available domestically in abundant supply. However, due to a number of barriers in the political, infrastructural, pricing and other arenas, the use of natural gas as a significant energy source in the United States has been limited. In our paper, we highlight the favorable qualities of natural gas and its benefits for the consumer, producer, and environment, having compared the costs of the various components of the natural gas business such as drilling and transport to that of coal and oil. Moreover, we touch upon the major issues that have prevented a more prevalent use of the gas, such as the fact that the infrastructure of natural gas is more costly since it is transported though pipelines whereas other energy sources such as oil and coal have flexible systems that use trains, trucks and ships. In addition, the powerful lobbies of the coal and oil businesses, along with the inertia in the congress to pass a national climate change bill further dampens incentives for these industries to invest in natural gas, despite its various attractive qualities. We also include discussions of policy proposals to incentive greater use of natural gas in the future. [ABSTRACT FROM AUTHOR]

In a spatial property modeling context, the variables of interest to be modeled often display complex nonlinear features. Techniques to incorporate these nonlinear features, such as multiple point statistics or cummulants, are often complex with input parameters that are difficult to infer. The methodology proposed in this paper uses a classical vector-based definition of locally varying anisotropy to characterize nonlinear features and incorporate locally varying anisotropy into numerical property models. The required input is an exhaustive field of anisotropy orientation and magnitude. The methodology consists of (1) using the shortest path distance between locations to define the covariance between points in space (2) multidimensional scaling of the domain to ensure positive definite kriging equations and (3) estimation or simulation with kriging or sequential Gaussian simulation. The only additional parameter required when kriging or simulating with locally varying anisotropy is the number of dimensions to retain in multidimensional scaling. The methodology is demonstrated on a CO emissions data set for the United States in 2002 and shows an improvement in cross validation results as well as a visual reproduction of nonlinear features. [ABSTRACT FROM AUTHOR]

In 2009, the National Research Council issued Electricity from Renewables: Status, Prospects, and Impediments the study report of the Panel on Electricity from Renewable Sources. As part of the larger America's Energy Future study undertaken by the National Academies, the panel was asked to examine the technical potential for development and deployment of renewable electricity technologies. This paper summarizes the report by this panel. The panel noted that renewable electricity generation technologies represent a tremendous opportunity to provide low net carbon dioxide (CO2)-emitting electricity generation from domestic resources and to generate new economic opportunities for the United States. The panel found that there are sufficient domestic renewable resources and technologies to allow renewable electricity to play a significant role in future electricity generation. However, although wind and solar electricity in particular have exhibited very large growth rates, non-hydropower renewables still provide a small percentage of total US electricity generation. The study considered the size and distribution of the resource base; the status of renewable electricity technologies; the economics of renewable electricity in light of various policy options; the environmental impacts of electricity from renewable resources; and the issues related to scaling up deployment. The panel concluded that an aggressive but achievable future for renewables could have non-hydroelectric renewables contributing 10% of the nation's electricity generation by 2020 and 20% or more by 2035. To reach these levels, significant and sustained actions, involving a combination and coordination of policy, technology, and capital, will be essential. The panel emphasizes policy, technology, and capital equally because the scale of the effort required to reach such levels brings significant challenges beyond simple resource availability or technical capabilities. [ABSTRACT FROM AUTHOR]

The Advanced Collaborative Emissions Study (ACES) program required the use of representative heavy-duty diesel engine activity. This need resulted in an engine test schedule creation program, and a schedule of engine modes representative of modern truck usage was developed based on data collected from engines in trucks operated through the heavy heavy-duty diesel truck (HHDDT) chassis schedule. The ACES test schedule included four active modes of truck operation including creep, transient, cruise, and high-speed cruise (HHDDT_S). This paper focuses on Phase 2 of the program, which was to validate and demonstrate the use of the ACES modes in a test cell. Preliminary testing was performed using a 1992 Detroit Diesel Corporation heavy heavy-duty diesel engine (HHDDE) on only the transient mode. On the basis of these results, each mode was modified slightly to suit implementation in a test cell. The locations of "closed throttle" points in the modes were determined through careful examination of the data. These closed throttle points were simulated during testing by adding negative set point torque values to the input file. After modification, all modes were tested during a final ACES modes demonstration period using a 2004 Cummins ISM HHDDE, obtaining three runs for each mode. During testing, carbon monoxide (CO), carbon dioxide (CO2), nitrogen oxides (NOx), particulate matter (PM), and hydrocarbon (HC) emissions were measured, and engine control unit (ECU) data were recorded. The new ACES modes did not adopt the Federal Test Procedure (FTP) regression criteria. New regression criteria for acceptability of a run were determined for each mode using the data obtained during testing. [ABSTRACT FROM AUTHOR]

This paper presents an energy and environmental network analysis model to explore tradeoffs associated with freight transport. The geospatial model uses an intermodal network built by the authors to connect various modes (rail, road, water) via intermodal terminals. Routes along the network are characterized not only by temporal and distance attributes, but also by cost, energy, and emissions attributes (including emissions of carbon dioxide, particulate matter, sulfur oxides, volatile organic compounds, and oxides of nitrogen). Decision-makers can use the model to explore tradeoffs among alternative route selection across different modal combinations, and to identify optimal routes for objectives that feature energy and environmental parameters (e.g., minimize carbon dioxide emissions). The model is demonstrated with three case studies of freight transport along the U.S. eastern seaboard. [ABSTRACT FROM AUTHOR]

Abstract: This paper reviews the Validation Phase (Phase II) of the Department of Energy''s Regional Carbon Sequestration Partnerships initiative. In 2003, the U.S. Department of Energy created a nationwide network of seven Regional Carbon Sequestration Partnerships (RCSP) to help determine and implement the technology, infrastructure, and regulations most appropriate to promote carbon sequestration in different regions of the nation. The objectives of the Characterization Phase (Phase I) were to characterize the geologic and terrestrial opportunities for carbon sequestration; to identify CO2 point sources within the territories of the individual partnerships; to assess the transportation infrastructure needed for future deployment; to evaluate CO2 capture technologies for existing and future power plants; and to identify the most promising sequestration opportunities that would need to be validated through a series of field projects. The Characterization Phase was highly successful, with the following achievements: established a national network of companies and professionals working to support sequestration deployment; created regional and national carbon sequestration atlases for the United States and portions of Canada; evaluated available and developing technologies for the capture of CO2 from point sources; developed an improved understanding of the permitting requirements that future sequestration activities will need to address as well as defined the gap in permitting requirements for large scale deployment of these technologies; created a raised awareness of, and support for, carbon sequestration as a greenhouse gas (GHG) mitigation option, both within industry and among the general public; identified the most promising carbon sequestration opportunities for future field tests; and established protocols for project implementation, accounting, and management. Economic evaluation was started and is continuing and will be a factor in project selection. During the Validation Phase, the seven regional partnerships will put the knowledge learned during the Characterization Phase into practice through field tests that will validate carbon sequestration technologies that are best suited to their respective regions of the country. These tests will verify technologies developed through DOE''s core R&D effort and enable implementation of CO2 sequestration on a large scale, should that become necessary. Pilot projects will have a site-specific focus to test technology; assess formation storage capacity and injectivity; validate and refine existing CO2 formation models used to determine the transport and fate of CO2 in the formation; demonstrate the integrity of geologic seals to contain CO2; validate monitoring, mitigation, and verification (MMV) technologies; define project costs and compare costs of alternatives; assess potential operational and long-term storage risks; address regulatory requirements; and engage and evaluate public acceptance of sequestration technologies. Field validation tests involving both sequestration in geologic formations and terrestrial sequestration are being developed. The results from the Validation Phase will help to confirm the estimates made during the Characterization Phase and will be used to update the regional atlases and NatCarb. Answers to many questions about the effectiveness and safety of carbon sequestration technologies will be instrumental in planning for a Deployment Phase, in which large volume tests will be planned to further sequestration as an option that can mitigate GHG emissions in the United States. [Copyright &y& Elsevier]

This paper provides comparisons of a variety of time-series methods for short-run forecasts of the main greenhouse gas, carbon dioxide, for the United States, using a recently released state-level data set from 1960–2001. We test the out-of-sample performance of univariate and multivariate forecasting models by aggregating state-level forecasts versus forecasting the aggregate directly. We find evidence that forecasting the disaggregate series and accounting for spatial effects drastically improves forecasting performance under root mean squared forecast error loss. Based on the in-sample observations we attempt to explain the emergence of voluntary efforts by states to reduce greenhouse gas emissions. We find evidence that states with decreasing per capita emissions and a “greener” median voter are more likely to push toward voluntary cutbacks in emissions. [ABSTRACT FROM AUTHOR]

Economic analyses of climate change policies frequently focus on reductions of energy-related carbon dioxide emissions via market-based, economy-wide policies. The current course of environment and energy policy debate in the United States, however, suggests an alternative outcome: sector-based and/or inefficiently designed policies. This paper uses a collection of specialized, sector-based models in conjunction with a computable general equilibrium model of the economy to examine and compare these policies at an aggregate level. We examine the relative cost of different policies designed to achieve the same quantity of emission reductions. We find that excluding a limited number of sectors from an economy-wide policy does not significantly raise costs. Focusing policy solely on the electricity and transportation sectors doubles costs, however, and using non-market policies can raise cost by a factor often. These results are driven in part by, and are sensitive to, our modeling of pre-existing tax distortions. [ABSTRACT FROM AUTHOR]

Abstract: This paper investigates injection of CO2 into non-dome-shaped geological structures that do not provide the traps traditionally deemed necessary for the development of artificial CO2 reservoirs. We have developed a conceptual and two numerical models of the geology and groundwater along a cross-section lying approximately NW–SE and in the vicinity of the Hunter power station on the Colorado Plateau, Central Utah and identified a number of potential sequestration sites on this cross-section. Preliminary modeling identified the White Rim Sandstone as appearing to offer the properties required of a successful sequestration site. Detailed modeling of injection of CO2 into the White Rim Sandstone using the reactive chemical simulator ChemTOUGH found that 1000 years after the 30 year injection period began approximately 21% of the injected CO2 was permanently sequestered as a mineral, 52% was beneath the ground surface as a gas or dissolved in the groundwater and 17% had leaked to the surface and leakage to the surface was continuing. [Copyright &y& Elsevier]

This paper describes a new suppressor technology for analyzing water samples using United States Environmental Protection Agency (EPA) methods 300.0 and 300.1. The Alltech DS-Plus suppressor improves and simplifies anion analysis in drinking water. In addition to suppressing the carbonate mobile phase and enhancing the analyte signal like conventional ion chromatography (IC) suppressors, the DS-Plus suppressor removes carbonic acid (as dissolved carbon dioxide) from the suppressor effluent before detection (US patent Nos.: 6 444 475; 6 468 804; others pending), lowering the background conductivity to near zero. Anions are detected in water background, improving sensitivity and lowering detection limits. The water-dip often seen with conventional suppressors is greatly reduced, improving fluoride quantification. The DS-Plus suppressor operates continuously without the need for external regenerants or switching valves. The performance of this new suppressor for analyzing water samples has been found to meet the EPA methods specifications. [Copyright &y& Elsevier]

This paper reports on the formation and dissolution of CO2/seawater/ CO2 hydrate composite particles produced during field experiments in Monterey Bay, CA using a CO2 injector system previously developed in the laboratory. The injector consisted of a coflow reactor wherein water was introduced as a jet into liquid CO2, causing vigorous mixing of the two immiscible fluids to promote the formation of CO2 hydrate that is stable at ambient pressures and temperatures typical of ocean depths greater than ∼500 m. Using flow rate ratios of water and CO2 of 1:1 and 5:1, particulate composites of CO2 hydrate/liquid CO2 seawater phases were produced in seawater at depths between 1100 and 1300 m. The resultant composite particles were tracked by a remotely operated vehicle system as they freely traveled in an imaging box that had no bottom or top walls. Results from the field experiments were consistent with laboratory experiments, which were conducted in a 70 L high-pressure vessel to simulate the conditions in the ocean at intermediate depths. The particle velocity and volume histories were monitored and used to calculate the conversion of CO2 into hydrate and its subsequent dissolution rate after release into the ocean. The dissolution rate of the composite particles was found to be higher than that reported for pure CO2 droplets. However, when the rate was corrected to correspond to pure CO2, the difference was very small. Results indicate that a higher conversion of liquid CO2 to CO2 hydrate is needed to form negatively buoyant particles in seawater when compared to freshwater, due primarily to the increased density of the liquid phase but also due to processes involving brine rejection during hydrate formation. [ABSTRACT FROM AUTHOR]

With electric generation responsible for 41 percent of U.S anthropogenic carbon dioxide (CO2) emissions from energy use, development of clean energy sources is essential if the United States is to reduce release of greenhouse gases and slow global warming. Many proponents of sustainable energy anticipate that electric generation from renewable sources would thrive in a deregulated market, driven by consumer demand for “green” energy and the end of incentives to build large central power plants under the cost-plus profits guaranteed by state utility commissions. This paper examines the flaws in this expectation. After reviewing the highly cyclical nature of U.S. energy policy making in recent decades, the study links the ineffectiveness of policy with the institutional setting. Under electric utility market restructuring, renewable energy generation (wind, biomass, solar, geothermal, and small-scale hydro) must overcome barriers such as price distortions, lack of storage capability, discriminatory transmission system access, and the end of linked utility rate hikes guaranteed to cover the additional expense of renewable generation. In the absence of strong federal leadership, the state commitment to renewable energy has been uneven under utility restructuring. Moreover, nuclear power—the other leading alternative to fossil fuel use—is beset by serious problems. Only renewable energy options offer long-term hope for sustainability. Along these lines, green marketing, renewable portfolio standards, system benefit charges, carbon taxes, public power, “Community Choice,” and production credits—all based on recent U.S. and European experience—are critically examined and recommendations made for changing course. At present, during this highly fluid period of utility restructuring, and absent more forceful regulation and demand management, it is dubious whether U.S. electricity market reform can encourage sufficient conversion to renewable energy to stem a rising tide of greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

In 1992 the US Environmental Protection Agency (EPA) introduced Energy Star®, a voluntary labeling program designed to identify and promote energy-efficient products, in order to reduce carbon dioxide emissions. Since then, the EPA, now in partnership with the US Department of Energy (DOE), has expanded the program to cover nearly the entire buildings sector, spanning new homes, commercial buildings, residential heating and cooling equipment, major appliances, office equipment, commercial and residential lighting, and home electronics. This paper is based on our experience since 1993 in providing technical support to the Energy Star program. We provide a snapshot of the Energy Star program in the year 2000, including a general overview of the program, its accomplishments, and the possibilities for future development. [Copyright &y& Elsevier]

Many energy systems models have sought to develop pathways for deep decarbonization of the global energy system. Most often, these pathways minimize system costs or greenhouse gas emissions; with few exceptions, they ignore the constraints imposed by political, social, and economic factors that slow transition processes, making them prone to producing implausible decarbonization pathways. This paper integrates a key socio-technical factor—social acceptance of low-carbon nuclear power—into an energy systems model to illustrate how it alters the optimal energy generation mix. The United States was chosen as the example, but the approach itself is designed to be general and applicable to any region of interest. An empirically grounded risk tolerance model is developed to characterize acceptance of nuclear power and estimate an upper-bound deployment limit for the technology. Illustrative scenarios are presented to improve our understanding of how the socio-technical constraints that exist in the real world can alter deep decarbonization pathways. The cost-optimal generation portfolio to achieve net zero CO 2 emissions by 2050 primarily relies on nuclear power. If risk tolerance concerns constrain nuclear deployment to socially acceptable levels, deep decarbonization scenarios are up to 11% more expensive than the reference scenario and require low-carbon options to be available and replace the reduced nuclear share. Results from this novel framework improve our representation of the effect of social acceptance on the adoption and diffusion of energy technologies. They also contribute to a growing literature that seeks to firmly embed the social sciences in climate and energy policy. • Plausible decarbonization pathways must also account for social constraints. • We combine a social risk tolerance model with an energy system optimization model. • We assess the role of social acceptance in constraining nuclear power's deployment. • Social acceptance limits nuclear's share by as much as 71% in CO 2 reduction pathways. • Decision-making can be strengthened with integration of socio-technical analyses. [ABSTRACT FROM AUTHOR]

The recent historical increase in energy-related CO 2 emissions globally have put the United States of America's (USA) transportation sector in the spotlight, courtesy of the significantly high pollutant emissions from this particular sector. Taking a cue from this, this paper follows sustainable development goals of the United Nations, and investigates the impact of biomass energy consumption, fossil fuel energy consumption, and economic growth (GDP) on carbon dioxide (CO 2) emissions in the transportation sector of the USA. In doing so, this study also employs the Gregory-Hansen cointegration, Hatemi-J cointegration, cointegration regression (FMOLS, DOLS, and CCR), and Spectral Breitung-Candelon causality test for the period between 1981Q1 and 2019Q4. The findings reveal that (i) a significant nonlinear cointegration among the environmental quality determinants is observed, using the threshold cointegration test. This test determines the structural breaks endogenously and combines two cointegration tests, namely the Gregory-Hansen Cointegration and Hatemi-J Cointegration tests; (ii) while the use of biomass energy consumption and real GDP have a negative effect on CO 2 emissions in the transportation sector, the rising fossil fuel energy consumption is associated with increasing the CO 2 emissions that are stemming from the transportation sector; (iii) in the long-run, biomass energy consumption, fossil fuel energy consumption, and real GDP cause CO 2 emissions to stem from the transportation sector in the USA at different frequency levels. In general, the current study offers policy insights for the transportation sector of the USA and other similar economies that replicate the same conditions. Image 1 • We explore the driving forces of CO 2 emissions in the transport sector for the USA. • We employ advanced time series econometric techniques for empirical analysis. • Biomass energy and real GDP help to mitigate CO 2 emissions in the transport sector. • Fossil fuel energy has a positive impact on CO 2 emissions in the transport sector. • All variables have a causative relationship with CO 2 emissions in the long-run. [ABSTRACT FROM AUTHOR]

Presents a study which found that the fractionation of a photosynthetic carbon is affected by variations in diffusive transport of carbon dioxide into phytoplankton cells in Monterey Bay, California. Implications of variation in C fractionation in plankton; Methods and results; Discussion.