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In the present paper, national and externally organized projections of greenhouse gas emissions for Austria were compared to gain insight on the underlying scenario data assumptions. National greenhouse gas emission trends extend until 2030, an assessment of European Union (EU) countries to 2050. In addition, data for 2000-2100 was extracted from the global emission database described by the Representative Concentration Pathways (RCP). By identifying trends in these projections, it was possible to produce (a) a long-term assessment of national scenarios until 2100, (b) an assessment of the ambition level toward national climate strategies, and (c) a standardized method to compare trends across countries. By extracting RCP data, Austrian's methane, nitrous oxide, and carbon dioxide emissions up to 2100 could be projected for all sources as well as specific sectors. With respect to the RCP scenario emission data, national projections did not seem to employ the mitigation potentials available for the most stringent RCP scenario, RCP2.6. Comparing projections that supported the EU Climate Strategy 2030 with national projections revealed similar trends. Because RCP2.6 is the only scenario consistent with a 2 °C global warming target, and it is much more ambitious than any of the national or European projections, further measures will be required if Austria is to adequately contribute to this widely accepted policy goal. [ABSTRACT FROM AUTHOR]

Enterprises are the market players for carbon reductions and carbon trading, and they are also the significant driving force in a low-carbon economy and society. Using the data of A-share listed companies from 2010 to 2016, this study uses a difference-in-differences (DID) model to examine the effects of the low-carbon city construction on corporate carbon reduction performance. Consistent with our hypotheses, we find that the low-carbon city construction promotes corporate carbon reduction performance. Further analysis indicates that the policy effect is stronger for state-owned enterprises (SOEs) than non-state-owned enterprises (non-SOEs). Moreover, environmental quality can affect the promotion of local government officials, which is more prominent in pilot low-carbon cities, and political promotion incentives significantly improve corporate carbon reduction performance. Furthermore, the highest emission reduction effects come in the fourth year after adopting a carbon reduction policy and are concentrated among the firms in the eastern region. Overall, our findings offer a new point view for a deeper understanding of the improvement of corporate carbon reduction performance, and provide microscopic evidence for the objective evaluation of the environmental effects of China's low-carbon city pilot policies. [ABSTRACT FROM AUTHOR]

Accurate assessment of the cost of carbon sequestration is important for the development of mitigation policies globally. Given that sequestration in soils or vegetation is a lengthy process, such assessment requires financial discounting and making realistic assumptions about changes over time in the rate of sequestration, the price of carbon, and the opportunity cost incurred by adopting sequestration practices. Our objective is to demonstrate how these assumptions affect estimates of the cost of sequestration-based mitigation strategies. Using an Australian case study of soil carbon sequestration, our estimates of the carbon price required for financial viability are highly sensitive to dynamic assumptions, varying by a factor of four with different assumptions. Yet the influence of these time-related assumptions is poorly acknowledged in the literature, with many studies either failing to disclose their assumptions, or employing questionable assumptions and methods. Recommended global strategies are for researchers to report their assumptions related to dynamics much more transparently and to improve their research methods and the realism of their assumptions when analysing the economics of carbon sequestration. We recommend that policymakers become better aware of the issues created by dynamics, so that they are able to validly interpret assessments of the cost of sequestration and to ensure that they design policies in a way that facilitates fair comparison of the costs of mitigation strategies that operate over different timescales. [ABSTRACT FROM AUTHOR]

Deep emission cuts rely on the use of low carbon technologies like renewable energy or carbon capture and storage. There is considerable uncertainty about their future costs. We carry out a sensitivity analysis based on Gauss Quadrature for cost parameters describing these technologies in order to evaluate the effect of the uncertainty on total and marginal mitigation costs as well as composition changes in the energy system. Globally, effects in total cost often average out, but different regions are affected quite differently from the underlying uncertainty in costs for key abatement technologies. Regions can be either affected because they are well suited to deploy a technology for geophysical reasons or because of repercussions through international energy markets. The absolute impact of uncertainty on consumption increases over the time horizon and with the ambition of emission reductions. Uncertainty in abatement costs relative to expected abatement costs are however larger under a moderate ambition climate policy scenario because in this case the marginal abatement occurs in the electricity sector where the cost uncertainty is implemented. Under more ambitious climate policy in line with the two degree target, the electricity sector is always decarbonized by 2050, hence uncertainty has less effect on the electricity mix. The findings illustrate the need for regional results as global averages can hide distributional consequences on technological uncertainty. [ABSTRACT FROM AUTHOR]

Livestock [inclusive of ruminant species, namely cattle ( Bos Taurus and Bos indicus), sheep ( Ovis aries), goats ( Capra hircus), and buffaloes ( Bubalus bubalis), and non-ruminant species, namely pigs ( Sus scrofa domesticus) and chickens ( Gallus domesticus)] are both affected by climate change and contribute as much as 14.5 % of global anthropogenic greenhouse gas (GHG) emissions, most of which is from ruminant animals (Gerber et al. 2013). This study aims to estimate the marginal costs of reducing GHG emissions for a selection of practices in the ruminant livestock sector (inclusive of the major ruminant species-cattle, sheep, and goats) globally. It advances on previous assessments by calculating marginal costs rather than commonly reported average costs of abatement and can thus provide insights about abatement responses at different carbon prices. We selected the most promising abatement options based on their effectiveness and feasibility. Improved grazing management and legume sowing are the main practices assessed in grazing systems. The urea (CO(NH)) treatment of crop straws is the main practice applied in mixed crop-livestock systems, while the feeding of dietary lipids and nitrates are confined to more intensive production systems. These practices were estimated to reduce emissions by up to 379 metric megatons of carbon dioxide (CO) equivalent emissions per year (MtCO-eq yr). Two thirds of this reduction was estimated to be possible at a carbon price of 20 US dollars per metric ton of CO equivalent emissions ($20 tCO-eq). This study also provides strategic guidance as to where abatement efforts could be most cost effectively targeted. For example, improved grazing management was particularly cost effective in Latin America and Sub-Saharan Africa, while legume sowing appeared to work best in Western Europe and Latin America. [ABSTRACT FROM AUTHOR]

Most modelling studies that explore long-term greenhouse gas mitigation scenarios focus on cost-efficient emission pathways towards a certain climate target, like the internationally agreed target to keep global temperature increase below 2 °C compared to pre-industrial levels (the 2 °C climate target). However, different timing of reductions lead to different transient temperature increase over the course of the century and subsequently to differences in the time profiles of not only the mitigation costs but also adaptation costs and residual climate change damage. This study adds to the existing literature by focussing on the implication of these differences for the evaluation of a set of three mitigation scenarios (early action, gradual action and delayed action), all three limiting global temperature increase below 2 °C above pre-industrial levels, using different discount rates. The study shows that the gradual mitigation pathway is, for these discount rates, preferred over early or delayed action in terms of total climate costs and net benefits. The relative costs and benefits of the early or delayed mitigation action scenarios, in contrast, do strongly depend on the discount rate applied. For specific discount rates, these pathways might therefore be preferred for other reasons, such as reducing long-term uncertainty in climate costs by early action. [ABSTRACT FROM AUTHOR]

Using micrometeorological techniques to measure greenhouse gas emissions from differently treated adjacent plots is a promising avenue to verify the effect of mitigation strategies at the field scale. In pursuing such an approach, it is crucial to accurately characterize the source area of the fluxes measured at each sampling point. Hence, a comprehensive footprint analysis method is required so that emission rates can be obtained for a specific field within a biochemically heterogeneous area. In this study, a footprint analysis method is developed to estimate the emission for an experiment where the flux of NO is measured from several control and treated plots. The emission rate of an individual plot is estimated using an inverse footprint fraction approach where the footprint fractions are obtained from an analytical footprint model. A numerical solution for obtaining the background flux for such a multiplot measurement system is also provided. Results of the footprint analysis method are assessed, first, by comparing footprint fractions obtained from both an analytical footprint model and a 'forward' simulation of a backward Lagrangian stochastic (bLs) model; and second, by comparing the emission rates of a control plot obtained from the footprint analysis method and from the 'backward' simulation of the bLs model. It is found that the analytical footprint fractions compare well with the values obtained from the bLs model (correlation coefficient of 0.58 and 0.66 within p value <0.001). An average of 4.3 % of the measured fluxes is found to be contributed by sources outside the measured area and, excluding this outside area contribution to the measured flux, footprint corrected emission rates within the defined domain are found to increase by 2.1 to 5.8 % of the measured flux. Also, the proposed method of emission rate estimation is found to work well under a wide range of atmospheric stability. [ABSTRACT FROM AUTHOR]