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1.
Different from previous studies which mainly focused on conventional estimation techniques, this paper examines the CO 2 EKC hypothesis of China using a spatial panel data model to avoid the coefficient estimation error covering the period of 1997–2012. Furthermore, a comparative analysis of the turning points between the non-spatial panel model and spatial panel model is conducted. The results show that the relationship between economic growth and CO 2 emissions shapes as an inverted-N trajectory. Spatial spillovers effects are confirmed to affect the shape of the CO 2 environmental Kuznets curve. There exists an apparent block distribution in spatial structure of China's provincial CO 2 emissions. Specifically, CO 2 emissions have a relatively sharp increase from the eastern regions to the central and the western regions of China. It has also been found that urbanization and coal combustion are main factors on increasing CO 2 emissions. While the trade openness contributes to slight decrease in CO 2 emissions. The government should make targeted carbon-reduction policies for CO 2 emission reduction. 相似文献
2.
城市是碳排放最集中的区域,全面厘清城市空间结构对碳排放的影响对碳减排规划具有重要意义。以往研究主要关注城市二维结构与碳排放的关系,表明城市扩张是碳排放剧增的主要原因。虽然城市三维空间结构也会显著影响碳排放,然而其影响的尺度效应依然缺少深入分析。为此以广州市为例,结合相关性分析、随机森林探究三维空间结构与碳排放的关系,并揭示三维空间结构影响的尺度效应。研究结果表明:(1)(高层)建筑物密度、建筑覆盖率、容积率与人口密度是碳排放的关键影响因素,主要通过直接增加人类活动或加剧热岛效应使得能源消耗和碳排放增多;(2)三维空间结构对碳排放的影响具有明显的尺度效应。随着分析尺度的变化,碳排放受三维空间结构的不同方面主导;(3)广州作为紧凑型城市的代表,如果片面追求城市三维空间的紧凑布局将不利于低碳城市的发展。因此,相关部门应重视宏观尺度下的三维空间结构的合理布局,合理开发城市边缘地区,降低城市中心建筑物的紧凑布局,构建多中心的城市格局,以有效降低碳排放水平,促进低碳城市的构建与可持续发展。研究所得成果可为城市建筑三维空间布局的合理优化提供参考依据,助力"双碳"目标的实现。 相似文献
3.
Understanding the responses of soil nitrous oxide (N 2O) emissions from terrestrial ecosystems to future CO 2 enrichment and warming is critical for the development of mitigation and adaptation policies. The effects of continuous increase in elevated CO 2 (EC) and elevated temperature (ET) on N 2O emissions are not fully known. We synthesized 209 measurements from 70 published studies and carried out a meta-analysis to examine individual and interactive effects of EC and ET on N 2O emissions from grasslands, croplands and forests. On average, a significant increase of 23% in N 2O emissions was observed under EC across all case studies. EC did not affect N 2O emissions from grasslands or forests, but significantly increased N 2O emissions in croplands by 38%. The extent of ET effects on N 2O emissions was nonsignificant and there was no significant difference in N 2O emission responses among these three terrestrial systems. ET only promoted N 2O emissions in forest by about 32% when ET was less than 2°C. The interactive effect of EC and ET on N 2O emissions was significantly synergistic, showing a greater increase than the sum of the effects caused by EC and ET alone. Our findings indicated that the combination of EC and ET substantially promoted soil N 2O and highlighted the urgent need to explore its mechanisms to better understand N 2O responses under future climate change. 相似文献
4.
PurposeTechnologies with low environmental impacts and promoting renewable energy sources are required to meet the energetic demand while facing the increase of gas emissions associated to the greenhouse effect and the depletion of fossil fuels. CO2 methanation activated by magnetic heating has recently been reported as a highly efficient and innovative power-to-gas technology in a perspective of successful renewable energy storage and carbon dioxide valorisation. In this work, the life cycle assessment (LCA) of this process is performed, in order to highlight the environmental potential of the technology, and its competitivity with in respect to conventional heating technologies. MethodsThe IMPACT 2002+ was used for this LCA. The process studied integrates methanation, water electrolysis and CO2 capture and separation. This “cradle-to-gate” LCA study does not consider the use of methane, which is the reaction product. The functional unit used is the energy content of the produced CH4. The LCA was carried out using the energy mix data for the years 2020 and 2050 as given by the French Agency for Environment and Energy management (ADEME). Consumption data were either collected from literature or obtained from the LPCNO measurements as discussed by Marbaix (2019). The environmental impact of the CO2 methanation activated by magnetic heating was compared with the environmental impact of a power-to-gas plant using conventional heating (Helmeth) and considering the environmental impact of the natural gas extraction. ResultsIt is shown that the total flow rate of reactants, the source of CO2 and the energy mix play a major role on the environmental impact of sustainable CH4 production, whereas the lifetime of the considered catalyst has no significant influence. As a result of the possible improvements on the above-mentioned parameters, the whole process is expected to reduce by 75% in its environmental impact toward 2050. This illustrates the high environmental potential of the methanation activated by magnetic heating when coupled with industrial exhausts and renewable electricity production. ConclusionsThe technology is expected to be environmentally competitive compared with existing similar processes using external heating sources with the additional interest of being extremely dynamic in response, in line with the intermittency of renewable energy production. 相似文献
5.
The future trajectory of fossil fuel emissions is one of the largest uncertainties in predicting climate change. While global emissions scenarios are ultimately of interest for climate modeling, many of the factors that influence energy and fuel consumption operate on a local rather than global level. However, there have been relatively few comprehensive studies of the ecological and socioeconomic processes that will determine the future trajectory of net carbon dioxide (CO 2) emissions at local and regional scales. We conducted an interdisciplinary, whole ecosystem study of the role of climate, urban expansion, urban form, transportation, and the urban forest in influencing net CO 2 emissions in the Salt Lake Valley, Utah, a rapidly urbanizing region in the western U.S. Our approach involved a detailed emissions inventory validated with atmospheric measurements, as well as a system dynamics model of future CO 2 emissions developed in collaboration with local stakeholders. The model highlighted the importance of a positive feedback between urban land development and transportation investments that may strongly affect emissions by amplifying declines in developmental densities and increases in vehicular traffic. Simulations suggested that while doubling the density of tree planting would have a negligible effect on total urban CO 2 emissions, land use and transportation policies that dampen the intensity of the urban sprawl feedback could result in a 22% reduction in CO 2 emissions by 2030 relative to a business as usual scenario. We suggest that by advancing our mechanistic understanding of energy and fuel consumption regionally, this urban ecosystem approach has great potential for improving emissions scenario studies if replicated in other cities and urbanizing regions. 相似文献
6.
The present study explores the relationship between economic growth, electricity consumption, urbanization and environmental degradation in case of United Arab Emirates (UAE). The study covers the quarter frequency data over the period of 1975–2011. We have applied the ARDL bounds testing approach to examine the long run relationship between the variables in the presence of structural breaks. The VECM Granger causality is applied to investigate the direction of causal relationship between the variables. Our empirical exercise reported the existence of cointegration among the series. Further, we found an inverted U-shaped relationship between economic growth and CO 2 emissions i.e. economic growth raises energy emissions initially and declines it after a threshold point of income per capita (EKC exists). Electricity consumption declines CO 2 emissions. The relationship between urbanization and CO 2 emissions is positive. Exports seem to improve the environmental quality by lowering CO 2 emissions. The causality analysis validates the feedback effect between CO 2 emissions and electricity consumption. Economic growth and urbanization Granger cause CO 2 emissions. 相似文献
7.
BackgroundLittle is known about the combined impacts of global environmental changes and ecological disturbances on ecosystem functioning, even though such combined impacts might play critical roles in shaping ecosystem processes that can in turn feed back to climate change, such as soil emissions of greenhouse gases. Methodology/Principal FindingsWe took advantage of an accidental, low-severity wildfire that burned part of a long-term global change experiment to investigate the interactive effects of a fire disturbance and increases in CO 2 concentration, precipitation and nitrogen supply on soil nitrous oxide (N 2O) emissions in a grassland ecosystem. We examined the responses of soil N 2O emissions, as well as the responses of the two main microbial processes contributing to soil N 2O production – nitrification and denitrification – and of their main drivers. We show that the fire disturbance greatly increased soil N 2O emissions over a three-year period, and that elevated CO 2 and enhanced nitrogen supply amplified fire effects on soil N 2O emissions: emissions increased by a factor of two with fire alone and by a factor of six under the combined influence of fire, elevated CO 2 and nitrogen. We also provide evidence that this response was caused by increased microbial denitrification, resulting from increased soil moisture and soil carbon and nitrogen availability in the burned and fertilized plots. Conclusions/SignificanceOur results indicate that the combined effects of fire and global environmental changes can exceed their effects in isolation, thereby creating unexpected feedbacks to soil greenhouse gas emissions. These findings highlight the need to further explore the impacts of ecological disturbances on ecosystem functioning in the context of global change if we wish to be able to model future soil greenhouse gas emissions with greater confidence. 相似文献
8.
Purpose The environmentally friendly construction of agricultural infrastructure is much needed for sustainable development because construction is recognized as a cause of environmental degradation. The objective of this study was to estimate and characterize carbon dioxide (CO 2) emissions during construction of agricultural reservoir embankments for the quantitative environmental assessment and management of CO 2 emissions using life cycle assessment method. Methods Two reservoirs with different foundation treatment and construction components were selected in this study and their characteristics in CO 2 emissions were compared. And CO 2 emissions were calculated separately for each of the following major components: construction materials, equipment, and transport. The basic unit of CO 2 emissions for construction materials was calculated using the 2009 input–output tables in Korea and the basic unit of CO 2 emissions for equipment of transport and construction was also calculated based on the amount of fuel used in a unit time. Results and discussion According to the study results, the construction of a water supply process appeared to generate the most emissions among all processes for the two sites. Emissions due to equipment were the highest in site A, while materials generated the most emissions in site B. Differences in emissions are due to differences in the construction process. While the operation time of the equipment in site A increased due to the cofferdam process and a large amount of cement was used in the foundation process in site B. Conclusions Characteristic of CO 2 emissions differs with different construction processes and thus construction processes need to be optimized for environmental friendly development of agricultural infrastructure through estimation and characterization of CO 2 emissions. 相似文献
9.
The present study investigates the dynamic relationship between energy intensity and CO 2 emissions by incorporating economic growth in environment CO 2 emissions function using data of Sub Saharan African countries. For this purpose, we applied panel cointegration to examine the long run relationship between the series. We employed the VECM Granger causality to test the direction of causality amid the variables.At panel level, our results validate the existence of cointegration among the series. The long run panel results show that energy intensity has positive and statistically significant impact on CO 2 emissions. There is also positive and negative link of non-linear and linear terms of real GDP per capita with CO 2 emissions supporting the presence of environmental Kuznets curve (EKC). The causality analysis reveals the bidirectional causality between economic growth and CO 2 emissions while energy intensity Granger causes economic growth and hence CO 2 emissions, while across the individual countries, the results differ. This paper opens up new insights for policy makers to design comprehensive economic, energy and environmental policy for sustainable long run economic growth. 相似文献
10.
We investigate the extent to which Japanese people can change their consumption and the corresponding environmental impact. We propose a new analytical framework with a rebound matrix that captures the monetary flow from potential savings to their respending (referred to as rebound). A questionnaire is used to derive the matrix. On average, respondents spent 3.4 million Yen annually, resulting in 12.4 tons of carbon dioxide (CO 2) emissions in their daily lives. The survey results suggest that acceptable spending reductions would correspond to a CO 2 emissions reduction of nearly 6%. However, the CO 2 emissions would increase by nearly the same amount when the respondents respend their savable money (rebound CO 2 emissions). The annual CO 2 emissions and the annually reducible CO 2 emissions both increase with the increase in annual expenditure. Consequently, the net CO 2 emissions also increase with the increase in annual expenditure. The rebound spending is approximated using the rebound matrix. Finally, it is suggested that the net CO 2 emissions can be reduced through lifestyle changes whereby spending on energy items is reduced and the resulting savings are spent on telecommunication, clothes, shoes, education, and housing. 相似文献
11.
旅游业作为全球第一大产业,是影响气候变化的重要因素之一,旅游碳排放的相关研究近年来已经引起学者们的关注.选择了九寨沟风景区、西安碑林博物馆、南京珍珠泉风景区3个旅游交通模式差异明显的案例地为例,根据实地问卷调查数据估算了九寨沟风景区、西安碑林博物馆、珍珠泉旅游风景区2010年的旅游交通碳排放总量分别为654.18,108.44和15.92 Gg.通过比较九寨沟、西安碑林和珍珠泉的碳排放累积曲线,得出不同旅游平均距离的景区的碳排放结构均衡度有所不同,旅游平均距离偏低景区的碳排放结构最不均衡.同时,旅游景区的交通碳排放在距离上具有分段性,不同旅游平均距离的景区交通碳排放的空间结构具有明显的差异性.通过4种不同的交通情景分析发现,旅游平均距离高和距离中等的景区对飞机的碳减排敏感度较高,旅游平均距离偏低的景区自驾车的碳减排效果最为明显.研究结果为旅游管理部门根据碳排放结构有针对性的制定差异化的旅游交通碳减排政策提供了参考和借鉴. 相似文献
12.
选择联合国政府间气候变化专门委员会(IPCC)的部门方法和8大类能源,采用1990年至2009年的中国能源统计数据,按照自下而上的思路,对我国各省区的碳排放量进行估算,并从碳排放量、碳排放强度、人均碳排放量和碳排放密指标出发,深入分析了各省区碳排放的时空特征差异。以期对国内碳排放的时空特征分析,有助于决策者和能源分析家提高节能减排政策制定的有效性。 相似文献
13.
Background, aim, and scope One of the most important sources of global carbon dioxide emissions is the combustion of fossil fuels for power generation.
Power plants contribute more than 40% of the worldwide anthropogenic CO 2 emissions. Therefore, the increased requirements for climate protection are a great challenge for the power producers. In
this context a significant increase in power plant efficiency will contribute to reduce specific CO 2 emissions. Additionally, CO 2 capture and storage (CCS) is receiving considerable attention as a greenhouse gas (GHG) mitigation option. CCS allows continued
use of fossil fuels with no or little CO 2 emissions given to the atmosphere. This could approve a moderate transition to a low-carbon energy generation over the next
decades. Currently, R&D activities in the field of CCS are mainly concentrated on the development of capture techniques, the
geological assessment of CO 2 storage reservoirs, and on economic aspects. Although first studies on material and energy flows caused by CCS are available,
a broader environmental analysis is necessary to show the overall environmental impacts of CCS. The objectives in this paper
are coal-based power plants with and without CO 2 capture via mono-ethanolamine (MEA) and the comparison of their environmental effects based on life cycle assessment methodology
(LCA). 相似文献
14.
The central focus of this article is to assess the dynamic effects of nuclear and renewable energy consumption on CO 2 emissions, for a given level of income and energy consumption. We apply an autoregressive distributed lag (ARDL) approach to cointegration to U.S. data from 1960 to 2010. We find that nuclear energy consumption indeed reduces CO 2 emissions in both the short- and long-run, while renewable energy consumption does only in the short-run. We also find that income increases CO 2 emissions in the long-run after showing the environmental Kuznets curve (EKC) initially in the short-run. Finally, energy consumption is found to have a negative impact on reducing CO 2 emissions in the short- and long-run. 相似文献
15.
The action required to stem the environmental and social implications of climate change depends crucially on how humankind shapes technology, economy, lifestyle and policy. With transport CO 2 emissions accounting for about a quarter of the total, we examine the contribution of CO 2 output by scientific travel. Thankfully for the reputation of the scientific community, CO 2 emissions associated with the trips required to present a paper at a scientific conference account for just 0.003% of the yearly total. However, with CO 2 emissions for a single conference trip amounting to 7% of an average individual’s total CO 2 emissions, scientists should lead by example by demonstrating leadership in addressing the issue. 相似文献
16.
Purpose This study seeks to answer the question, “Will the Million Trees LA (Million Trees Los Angeles, MTLA) program be a carbon dioxide (CO 2) sink or source?” Because there has never been a full accounting of CO 2 emissions, it is unclear if urban tree planting initiatives (TPIs) are likely to be effective means for reaching local reduction targets. Methods Using surveys, interviews, field sampling, and computer simulation of tree growth and survival over a 40-year time period, we developed the first process-based life cycle inventory of CO 2 for a large TPI. CO 2 emissions and reductions from storage and avoided emissions from energy savings were simulated for 91,786 trees planted from 2006 to 2010, of which only 30,813 (33.6 %) were estimated to survive. Results and discussion The MTLA program was estimated to release 17,048 and 66,360 t of fossil and biogenic CO 2 over the 40-year period, respectively. The total amount emitted (83,408 t) was slightly more than the ?77,942 t CO 2 that trees were projected to store in their biomass. The MTLA program will be a CO 2 sink if projected 40-year-avoided fossil fuel CO 2 emissions from energy savings (?101,679 t) and biopower (?1,939 t) are realized. The largest sources of CO 2 emissions were mulch decomposition (65.1 %), wood combustion (14.5 %), and irrigation water (9.7 %). Conclusions Although trees planted by the MTLA program are likely to be a net CO 2 sink, there is ample opportunity to reduce emissions. Examples of these opportunities include selecting drought-tolerant trees and utilizing wood residue to generate electricity rather than producing mulch. 相似文献
17.
Cities are rapidly growing and need to look for ways to optimize resource consumption. Metropolises are especially vulnerable in three main systems, often referred to as the FEW (i.e., food, energy, and water) nexus. In this context, urban rooftops are underutilized areas that might be used for the production of these resources. We developed the Roof Mosaic approach, which combines life cycle assessment with two rooftop guidelines, to analyze the technical feasibility and environmental implications of producing food and energy, and harvesting rainwater on rooftops through different combinations at different scales. To illustrate, we apply the Roof Mosaic approach to a densely populated neighborhood in a Mediterranean city. The building‐scale results show that integrating rainwater harvesting and food production would avoid relatively insignificant emissions (13.9–18.6 kg CO 2 eq/inhabitant/year) in the use stage, but their construction would have low environmental impacts. In contrast, the application of energy systems (photovoltaic or solar thermal systems) combined with rainwater harvesting could potentially avoid higher CO 2 eq emissions (177–196 kg CO 2 eq/inhabitant/year) but generate higher environmental burdens in the construction phase. When applied at the neighborhood scale, the approach can be optimized to meet between 7% and 50% of FEW demands and avoid up to 157 tons CO 2 eq/year. This approach is a useful guide to optimize the FEW nexus providing a range of options for the exploitation of rooftops at the local scale, which can aid cities in becoming self‐sufficient, optimizing resources, and reducing CO 2 eq emissions. 相似文献
18.
We used a climate‐driven regression model to develop spatially resolved estimates of soil‐CO 2 emissions from the terrestrial land surface for each month from January 1980 to December 1994, to evaluate the effects of interannual variations in climate on global soil‐to‐atmosphere CO 2 fluxes. The mean annual global soil‐CO 2 flux over this 15‐y period was estimated to be 80.4 (range 79.3–81.8) Pg C. Monthly variations in global soil‐CO 2 emissions followed closely the mean temperature cycle of the Northern Hemisphere. Globally, soil‐CO 2 emissions reached their minima in February and peaked in July and August. Tropical and subtropical evergreen broad‐leaved forests contributed more soil‐derived CO 2 to the atmosphere than did any other vegetation type (~30% of the total) and exhibited a biannual cycle in their emissions. Soil‐CO 2 emissions in other biomes exhibited a single annual cycle that paralleled the seasonal temperature cycle. Interannual variability in estimated global soil‐CO 2 production is substantially less than is variability in net carbon uptake by plants (i.e., net primary productivity). Thus, soils appear to buffer atmospheric CO 2 concentrations against far more dramatic seasonal and interannual differences in plant growth. Within seasonally dry biomes (savannas, bushlands and deserts), interannual variability in soil‐CO 2 emissions correlated significantly with interannual differences in precipitation. At the global scale, however, annual soil‐CO 2 fluxes correlated with mean annual temperature, with a slope of 3.3 Pg C y ?1 per °C. Although the distribution of precipitation influences seasonal and spatial patterns of soil‐CO 2 emissions, global warming is likely to stimulate CO 2 emissions from soils. 相似文献
19.
Meeting the future food security challenge without further sacrificing environmental integrity requires transformative changes in managing the key biophysical determinants of increasing agronomic productivity and reducing the environmental footprint. Here, we focus on Chinese rice production and quantitatively address this concern by conducting 403 on-farm trials across diverse rice farming systems. Inherent soil productivity, management practices and rice farming type resulted in confounded and interactive effects on yield, yield gaps and greenhouse gas (GHG) emissions (N 2O, CH 4 and CO 2-equivalent) with both trade-offs and compensating effects. Advances in nitrogen, water and crop management (Best Management Practices—BMPs) helped closing existing yield gaps and resulted in a substantial reduction in CO 2-equivalent emission of rice farming despite a tradeoff of increase N 2O emission. However, inherent soil properties limited rice yields to a larger extent than previously known. Cultivating inherently better soil also led to lower GHG intensity (GHG emissions per unit yield). Neither adopting BMPs only nor improving soils with low or moderate productivity alone can adequately address the challenge of substantially increasing rice production while reducing the environmental footprint. A combination of both represents the most efficient strategy to harness the combined-benefits of enhanced production and mitigating climate change. Extrapolating from our farm data, this strategy could increase rice production in China by 18%, which would meet the demand for direct human consumption of rice by 2030. It would also reduce fertilizer nitrogen consumption by 22% and decrease CO 2-equivalent emissions during the rice growing period by 7% compared with current farming practice continues. Benefits vary by rice-based cropping systems. Single rice systems have the largest food provision benefits due to its wider yield gap and total cultivated area, whereas double-rice system (especially late rice) contributes primarily to reducing GHG emissions. The study therefore provides farm-based evidence for feasible, practical approaches towards achieving realistic food security and environmental quality targets at a national scale. 相似文献
20.
A large accumulation of carbon dioxide and other greenhouse gases have caused great concern around the world. A great deal of general literature focus on the impact factors of CO 2 emissions at the national, regional and city levels. However, there is little specific guidance on regional difference in CO 2 emissions. In this paper, 30 provincial-level administrative units of China are divided into three different levels of economic development regions according to the GDP per capita from 1997 to 2012. A STIRPAT (Stochastic Impacts by Regression on Population, Affluence and Technology) model is used to examine the impact factors on energy-related CO 2 emissions, including population, economic level, technology level, urbanization level, industrialization level and foreign trade degree. The results indicate that the effect of energy intensity is the greatest in highly developed region. Nevertheless, the impact of urbanization, industry structure and foreign trade degree in under developed region is higher than the other two regions. Population and GDP per capita have greater effect on carbon emissions in developing region than the others. Finally, differentiated measures for CO 2 reductions should be adopted according to local conditions of different regions. 相似文献
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