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Research has focused on the threat of global warming-induced climate change to modern human civilization. Carbon dioxide (CO2) is a primary greenhouse gas that causes global warming. Current efforts have focused on using CO2 as a raw source for producing value-added chemicals. Among the different CO2 conversion processes, the Sabatier process, also known as "CO2 methanation," is an effective approach, particularly if H2 is generated by renewable energy sources. In this process, methane (CH4) and water (H2O) are produced from CO2 and H2 using different transition-metal-based catalysts. Although numerous studies have been conducted to assess the significance of CO2 methanation, quantitative analysis of the publication trends in this research field is still lacking. This review presents the global research landscape of CO2 methanation over the last 20 years (2000–2022). The Web of Science (WoS) database was used to extract 1657 publications, and the VOSviewer software was used for bibliometric investigations. Bibliometric analysis revealed that 77.53% of the papers were published within the past 5 years (2018–2022). The International journal of hydrogen energy is leading journal publishing research articles about CO2 methanation followed by Applied Catalysis B. This study conducted a statistical analysis on the influence of leading countries, institutions, journals, authors, and top keywords in the field of CO2 methanation. Additionally, future research directions and findings of the most cited publications are discussed. Because the CO2 methanation reaction requires a highly stable and active catalyst, a brief introduction and major challenges of these catalysts are also reviewed. We hope that bibliometric findings will help scholars to understand this field of research more effectively and comprehensively. [ABSTRACT FROM AUTHOR]

This paper estimates changes in future energy demand and supply for Indiana due to projected climate change impacts. We first estimate demand changes under both the business-as-usual emissions scenario (RCP 8.5) and a scenario based on reduced emissions consistent with a 2-degree increase in global mean temperature (RCP 4.5), on both a statewide basis and for major urban areas. We then use our adjusted statewide energy demand projections as an input to a comprehensive model of Indiana's energy system, to project expected changes in the state's energy supply under both scenarios. Finally, we consider the potential impacts of two policy scenarios—a carbon pricing scheme and a renewable energy investment tax credit—on emissions and future energy supply choices. Our results suggest that climate change will have a relatively modest effect on energy demand and supply in Indiana, slightly increasing commercial demand and decreasing residential demand but having little effect on energy supply choices. In addition, our results suggest the potential for policy proposals currently being adopted in other states, such as a relatively small carbon price or investment credits for renewable energy sources, to have a larger impact on the state's future energy mix, increasing production from low or zero carbon energy sources and reducing emissions. [ABSTRACT FROM AUTHOR]

Lobbying is considered to be an important factor in the success or failure of climate change legislation. This paper provides an estimate of lobbying expenditures related to climate change legislation in the U.S. Congress from 2000 to 2016. During this time period, over $2 billion was spent on this activity, constituting 3.9% of total lobbying expenditures. Major sectors involved in lobbying were fossil fuel and transportation corporations, utilities, and affiliated trade associations. Expenditures by these sectors dwarf those of environmental organizations and renewable energy corporations. Levels of expenditures on lobbying appear to be related to the introduction and probability of passage of significant climate legislation. Future research should focus on tying particular positions on climate legislation and lobbying expenditures at the corporate level. [ABSTRACT FROM AUTHOR]

Climate change has repercussions on national security. Yet, no widely accepted definition of climate security exists to date. In this paper, we present a mathematical model that defines and assesses climate security as a function of 37 indicators of exposure, sensitivity, and adaptive capacity. The model combines the indicators using statistical methods and fuzzy logic which encapsulates the subjective part of the assessment, to derive an overall climate security score from 0 to 1, and then rank 187 countries. A sensitivity analysis points to those indicators with the highest potential to improve climate security and indicates regional priorities for action. It turns out that globally the highest priorities are the economy which is necessary for climate adaptation, population growth which should be contained, political rights, renewable energy use, and sea level rise. Although several results such as the high ranks of Scandinavian countries are intuitive, the model uncovers unexpected facts such as the higher rank of Uruguay than Denmark and Japan or the higher rank of Costa Rica than Italy. However, a closer look at the intermediate results reveals that Uruguay and Costa Rica are far superior to Denmark, Japan, and Italy in the areas of water and energy. [ABSTRACT FROM AUTHOR]

Energy efficiency is a central target for energy policy and a keystone to mitigate climate change and to achieve a sustainable development. Although great efforts have been carried out during the last four decades to investigate the issue, focusing into measuring energy efficiency, understanding its trends and impacts on energy consumption and to design effective energy efficiency policies, many energy efficiency-related concepts, some methodological problems for the construction of energy efficiency indicators (EEI) and even some of the energy efficiency potential gains are often ignored or misunderstood, causing no little confusion and controversy not only for laymen but even for specialists. This paper aims to revisit, analyse and discuss some efficiency fundamental topics that could improve understanding and critical judgement of efficiency stakeholders and that could help in avoiding unfounded judgements and misleading statements. Firstly, we address the problem of measuring energy efficiency both in qualitative and quantitative terms. Secondly, main methodological problems standing in the way of the construction of EEI are discussed, and a sequence of actions is proposed to tackle them in an ordered fashion. Finally, two key topics are discussed in detail: the links between energy efficiency and energy savings, and the border between energy efficiency improvement and renewable sources promotion. [ABSTRACT FROM AUTHOR]

Partly in response to concerns about anthropogenic climate change, renewable energy production is growing rapidly in the United Kingdom (UK). The wind power industry takes advantage of the country having some of the highest mean wind speeds in Europe. Future climate change, however, has the potential to alter the characteristics of the UK wind climate. Small changes in mean wind speed could produce much greater changes in wind energy output as the power generated is related to the cube of wind speed. This paper aims to use a simple method to provide insight into projected future UK wind climate and how this might differ from current patterns. A discussion of the scale of the projected impacts on the wind energy industry follows. [ABSTRACT FROM AUTHOR]

Comparative analysis of the energy and carbon balances of wood vs. non-wood products is a complex issue. In this paper we discuss the definition of an appropriate functional unit and the establishment of effective system boundaries in terms of activity, time and space, with an emphasis on the comparison of buildings. The functional unit can be defined at the level of building component, complete building, or services provided by the built environment. Energy use or carbon emissions per unit of mass or volume of material is inadequate as a functional unit because equal masses or volumes of different materials do not fulfil the same function. Activity-based system boundaries include life cycle processes such as material production, product operation, and post-use material management. If the products compared are functionally equivalent, such that the impacts occurring during the operation phase are equal, we suggest that this phase may be dropped from the analysis allowing a focus on material flows. The use of wood co-products as biofuel can be analytically treated through system expansion, and compared to an alternative of providing the same energy service with fossil fuels. The assumed production of electricity used for material processing is another important energy-related issue, and we suggest that using marginal production data is more appropriate than average production. Temporal system boundaries include such aspects of the wood life cycle as the dynamics of forest growth including regeneration and saturation, the availability of residue biofuels at different times, and the duration of carbon storage in products. The establishment of spatial boundaries can be problematic, because using wood-based materials instead of non-wood materials requires more land area to capture solar energy and accumulate biomass. We discuss several possible approaches to meet this challenge, including the intensification of land use to increase the time rate of biomass production. Finally, we discuss issues related to scaling up an analysis of wood substitution from the micro-level to the macro-level of national, regional or global. [ABSTRACT FROM AUTHOR]

There is considerable interest in the potential impact of climate change on the feasibility and predictability of renewable energy sources including wind energy. This paper presents dynamically downscaled near-surface wind fields and examines the impact of climate change on near-surface flow and hence wind energy density across northern Europe. It is shown that: Simulated wind fields from the Rossby Centre coupled Regional Climate Model (RCM) (RCAO) with boundary conditions derived from ECHAM4/OPYC3 AOGCM and the HadAM3H atmosphere-only GCM exhibit reasonable and realistic features as documented in reanalysis data products during the control period (1961–1990). The near-surface wind speeds calculated for a climate change projection period of 2071–2100 are higher than during the control run for two IPCC emission scenarios (A2, B2) for simulations conducted using boundary conditions from ECHAM4/OPYC3. The RCAO simulations conducted using boundary conditions from ECHAM4/OPYC3 indicate evidence for a small increase in the annual wind energy resource over northern Europe between the control run and climate change projection period and for more substantial increases in energy density during the winter season. However, the differences between the RCAO simulations for the climate projection period and the control run are of similar magnitude to differences between the RCAO fields in the control period and the NCEP/NCAR reanalysis data. Additionally, the simulations show a high degree of sensitivity to the boundary conditions, and simulations conducted using boundary conditions from HadAM3H exhibit evidence of slight declines or no change in wind speed and energy density between 1961–1990 and 2071–2100. Hence, the uncertainty of the projected wind changes is relatively high. [ABSTRACT FROM AUTHOR]