Flux of organic carbon burial and carbon emission from a large reservoir: implications for the cleanliness assessment of hydropower

This article estimated the size of carbon sink, emission, net carbon farmland ecosystem in China costal regions (including ten provinces) with statistic data from 1990 to 2010(which include crop yield and agricultural consumptions). Conclusions are as following: (1) the total carbon sink, emission and net of farmland ecosystem in China costal regions all increased since 1990. Carbon is obviously more than carbon emission, for example, total carbon in 2010 is 3 times more than carbon emission, which showed that the costal region is generally a sink region. While, because the increasing rate of carbon emission (265%) exceeded that of carbon (44%), the carbon function of farmland ecosystem in China costal regions will be saturated within several decades. (2) There were significant temporal-spatial differences in carbon sink, emission and net among different costal regions. Further, there are also differences in per area carbon sink, emission and net among different costal regions. The total and per area carbon emission increased year by year from 1990, while that of carbon and net changed drastically. The total carbon and net in relative developed regions has a down trend from 1990 to 2010. a special example: carbon emission exceeded carbon and caused that net carbon and per area net carbon was negative in 2010 in Shanghai, which indicated that Shanghai has been a carbon source region in 2010 because the decrease of cropland and increase of agricultural consumptions. (3) The proportion of carbon sinks in the main crops of farmland ecosystem in China costal regions compared with that of the whole nation decreased since 1990, which indicate that with the decrease of cropland and increase of agricultural consumptions, the carbon function of costal farmland is weaken.

The farmland system in the global terrestrial ecosystem has dual attributes as both a carbon source and a carbon sink, playing a crucial role in controlling carbon emissions and mitigating global warming. Using carbon source and sink accounting of farmland ecosystems, we applied methods such as standard deviation ellipse, Tapio decoupling theory, and Markov chain to analyze the spatiotemporal changes, response mechanisms, and evolutionary trends of regional carbon effects. The results indicated that from 2011 to 2021, the farmland ecosystem in the middle and lower reaches of the Yangtze River consistently acted as a carbon sink. However, the net carbon sink showed slight fluctuations and significant spatial differences. The migration range of the net carbon sink center in the farmland ecosystem of the middle and lower reaches of the Yangtze River was relatively small, ranging from 115.52 to 115.77° E and 30.14 to 30.27° N. The decomposition of the Tapio decoupling index between the net carbon sink of the farmland ecosystem and agricultural output value showed the order of effects on their coupling relationship as follows: agricultural mechanization level > agricultural mechanization efficiency > agricultural output value > planting scale. The probability of maintaining the original state of net carbon sink in various cities in the middle and lower reaches of the Yangtze River (over 77%) was much higher than the probability of transfer, making it difficult to achieve a leapfrog growth in net carbon sink. The net carbon sink at the city scale exhibits the Matthew effect and spatial spillover effect. The above research results clarify the spatiotemporal changes in carbon effects in agricultural production at multiple levels, including city, province, and region. They also provide a theoretical basis for formulating differentiated regional emission reduction and sink enhancement strategies in the middle and lower reaches of the Yangtze River, promoting the rapid development of low-carbon agriculture in China.

Carbon sink afforestation (CSA) has become one of the most concerned issues of countries around the world under the background of climate change. The northern forest ecosystem, located in mid- and high latitudes, is a huge terrestrial carbon pool and is very sensitive to climate change. Studying the carbon emission accounting of CSA in northern forests helps clarify the contribution of CSA to forestry carbon sequestration and forecasts the carbon sink effect of forest ecosystems. It is of great significance for the assessment of forest carbon sink and carbon cycling by providing a scientific basis and reference for the development, utilization, and management of carbon sink afforestation, as well as the coordinated development of ecology and social economy. At present, research on the carbon emission accounting of the CSA in northern China is still lacking. According to the relevant models and parameters of estimating live biomasses with the default method from the IPCC’s (Intergovernmental Panel on Climate Change) Technical Guidelines for National Forestry Carbon Sink Accounting and Monitoring, carbon stock, carbon emission, and carbon leakage of the Weihe CSA (carbon sink afforestation) pilot demonstration area in the boreal Longjiang Forest Industry in a baseline scenario and CSA scenario were measured, and the CSA’s net carbon sink was estimated. The conclusions were as follows: (1) By the end of the crediting period of the project’s baseline, carbon fixation reached 101.85 t CO2, with an average annual CO2 fixation of 5.09 t. By the end of the CSA term, carbon sequestration was accumulated as 382.13 t CO2, with an average annual sequestration of 19.11 t CO2, nearly four times that of the baseline period. (2) By the end of the CSA term, the carbon sequestration of the coniferous standing forest was 46.2% higher than that of the broad-leaved standing forest, accounting for 65% of the total carbon sequestration of the forest. The carbon sequestration of the tree species in the coniferous forest in descending order is Picea koraiensis, Pinus koraiensis, Larix olgensis, Fraxinus mandshurica, and Populus cathayana. The carbon sink density of the coniferous standing forest was 8.7% higher than that of the broad-leaved standing forest. (3) The carbon fixation of the coniferous standing forest nearly doubled that of the broad-leaved standing forest. The highest carbon fixation belongs to Fraxinus mandshurica, closely followed by Picea koraiensis and Pinus koraiensis at a high level, and then Larix olgensis and Populus cathayana. The carbon fixation of Fraxinus mandshurica was 20 times that of Populus cathayana. (4) The accumulated greenhouse gas emissions within the boundary during the CSA period were 2.53 t CO2-e. The accumulated greenhouse gas leakage outside the boundary was 0.05 t CO2-e. Carbon emissions occurred in the first, second, and third years of the crediting period, while carbon leakage occurred only in the first year. (5) This result appeared as carbon sources during the first three years of the CSA period but changed to carbon sink from the fourth year and then accumulated to 280.28 t (70.07 t CO2-e·hm−2) as a net carbon sink by the end of the term. The Weihe CSA appeared to have a relatively strong ability of carbon sequestration in temperate forests. The CSA activity is influenced by factors such as policies, environment, management, etc., resulting in uncertainties in carbon sequestration accounting. Therefore, it is suggested that comparison studies and investigations should be strengthened, and multiple methods should be integrated into carbon sequestration estimation and accounting, leading the carbon accounting of forest ecosystems to a high-level and comprehensive development.

Low-carbon agriculture is crucial for China's agricultural green transformation and the development of an ecological civilization. The net carbon sink of agriculture plays a vital role in this process. Here, we take China's 31 provinces （municipalities and autonomous regions） as the research object, select the data from 2000 to 2022, and discuss them from multiple perspectives around the three dimensions of time series, space, and coupling. Additionally, we constructed an environment-economy coupling index and refined it by phases to analyze the relationship between stages and regions. The study revealed the following： ① China's overall agricultural carbon emissions fluctuated and decreased, while the agricultural carbon sink continued to expand, showing steady growth. ② The net agricultural carbon sink was distributed among provinces, and the gap between provinces in terms of net carbon sink tended to widen. Agricultural net carbon sinks exhibited regional aggregation characteristics, forming two distinct growth areas. The traditional growth area comprised Shandong and Henan as the core and Hebei, Anhui, and Jiangsu as the neighboring radiation areas. The other emerging growth areas in Northeast China included Heilongjiang, Jilin, and Liaoning. ③ The net agricultural carbon sink demonstrated a clear positive spatial correlation. However, a tendency was observed for the spatial correlation to weaken and an increase in the spatial type of low-low form of aggregation over the years. ④ From 2000 to 2022, the coupling relationship between net agricultural carbon sinks and agricultural economic growth improved, with most provinces shifting from weak or strong decoupling to expanding negative decoupling. Six provinces, namely, Zhejiang, Fujian, Yunnan, Gansu, Xinjiang, and Inner Mongolia, have shown the most significant shifts. Overall, the net agricultural carbon sinks and agricultural economic growth are expected to be in a state of negative expansion or weak decoupling for a prolonged period in the future. While the contribution of agricultural carbon sinks to the resource reserve will be substantial, the sustainable growth of the agricultural economy will face challenges.

PDF HTML阅读 XML下载 导出引用 引用提醒 中国西北干旱区植被碳汇估算及其时空格局 DOI: 10.5846/stxb201405211045 作者: 作者单位: 西北师范大学 地理与环境科学学院,北京师范大学 资源学院 作者简介: 通讯作者: 中图分类号: S812；F062； 基金项目: 国家自然科学基金项目(41361040);甘肃省自然科学基金项目(1208RJZA159);甘肃省高校基本科研业务费项目(2014-63) Estimation and spatial-temporal characteristics of carbon sink in the arid region of northwest China Author: Affiliation: College of Geographic and Environmental Science,Northwest Normal University,College of Resources Science, Beijing Normal University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:通过修正的CASA模型估算2001-2012年间西北干旱区陆地生态系统的净第一性生产力(NPP),并结合土壤微生物呼吸方程,计算出12a的净生态系统生产力(NEP),分析了植被碳汇的时空变化规律。结果表明:研究区的NPP表现出很强的随季节变化的规律,全年7月份NPP为最高值,12月为最低值,12 年间NPP的年均值变化不大。2001-2012 年研究区的植被碳汇在波动变化中有所增加,其中2006年的碳汇平均值最小,为609.04 gC m-2 a-1,2012年最大,为648.02 gC m-2 a-1;年内碳汇的最大值主要出现在5-7月;碳汇能力由大到小的植被类型为针叶林 > 农田 > 灌丛 > 阔叶林 > 草原 > 荒漠草原。研究区多年平均碳汇量呈现自西向东逐渐增加的规律,西辽河流域草原区的NPP和碳汇平均值最大,塔里木盆地暖温带荒漠区最小。 Abstract:Global warming caused by greenhouse gas emissions has had a profound impact on human survival and development. Consequently, this phenomenon has received widespread attention from the international community. Vegetation can absorb greenhouse gases CO2, and has a huge carbon sink function, so it has an irreplaceable role in slowing global warming. The carbon sink capacity of vegetation has a significant impact on regional and global climate change. Carbon emissions are undoubtedly enormous in the mid and high latitudes of the Northern Hemisphere, so studies on terrestrial ecosystem carbon dynamics and spatial patterns in the arid region of northwest China may provide an accurate assessment how China contributes towards mitigating global climate change and CO2 emission reduction. The net primary productivity (NPP) and heterotrophic respiration (RH) in the arid region of northwest China were calculated by using MODIS images, meteorological data, and a vegetation type map, in combination with an improved CASA model and soil microbial respiration model. The NPP and RH were then used to estimate net ecosystem productivity (NEP) and vegetation carbon sink from 2001 to 2012. Spatial-temporal characteristics and the reasons for NPP and carbon sink variation in the arid region of northwest China were analyzed. The results show that research methods used in this paper were able to quickly extract ecosystem net primary productivity and carbon sink for the northwest arid region. The methods used are efficient, convenient, and practical for large scale carbon balance and carbon cycling studies in this region. Comparison indicated small gaps between simulated and measured site values. The overall difference in the spatial distribution between simulated values and MODIS NPP products is also small, and the volatility of the analog value is less than the value of MODIS NPP products. NPP in the study area showed strong seasonal variation. The maximal NPP value was obtained in July, while the minimum value was obtained in December. In the 12 study years, annual averages of NPP changed minimally. Average carbon sinks showed fluctuating in the 12 years, but increased in general, overall. The carbon sink mean changed from a minimum of 609.04 gC-1m-2a-1 in 2006 to a maximum of 648.02 gC-1m-2a-1 in 2012. The change in mean carbon sink was less than 39 gC-1m-2a-1, with a standard deviation of 11.68. Annual maximum carbon mainly occurred in May, June, and July. Carbon sink fluctuated, but showed an overall upward trend in the northwest arid region between 2001 and 2012. Carbon sink in this region gradually increased from West to East, with Eastern > West > Central. The carbon sink capacity of different natural areas was quite different. The largest carbon sink capacity was recorded in the grassland area of West Liaohe River Basin, while the smallest was recorded in the warm temperate desert region of the Tarim Basin. The annual maximum carbon sink mainly occurred from May to July. Carbon sink was ranked in the order of coniferous forest > farmland > shrubs > broad-leaved forest > grassland > desert steppe. 参考文献 相似文献 引证文献

Developing policies to reduce carbon emissions in agriculture is crucial for achieving the ‘dual carbon’ goal. Therefore, scientifically analysing the temporal and spatial distribution characteristics of agricultural carbon sinks and their driving factors holds paramount importance for the coordinated and integrated development of regional agriculture and the realization of sustainable development. Based on the perspective of carbon cycle in agricultural production, the measurement system of agricultural net carbon sink was established from the perspective of carbon sink/carbon source, this study conducted an analysis of the temporal and spatial variation characteristics as well as driving mechanisms of agricultural net carbon sinks. The findings are as follows: (1) The agricultural net carbon sink exhibited an increasing trend from 2009 to 2020, with favourable intensity and level. (2) Agricultural land use and livestock and poultry production constituted the primary sources of agricultural carbon emissions. Notably, agricultural carbon emissions demonstrated a decreasing trend during the study period. (3) The net agricultural carbon sink displayed local spatial aggregation, indicating significant regional differences. (4) Factors such as rural economic level, urbanization level and agricultural employment significantly promoted the net carbon sink. In contrast, the rural industrial structure, technical level and crop seeding had inhibitory effects. Therefore, it is imperative to promote the reduction of agricultural carbon emissions in the Beijing-Tianjin-Hebei region. This entails accelerating the construction of new agriculture and rural areas, facilitating industrial upgrading, promoting the development of low-carbon-sink regions into high-carbon-sink regions and actively fostering the coordinated and integrated development of regional agriculture.

Seaweed culture is of great significance in giving full play to the function of marine carbon sequestration and strengthening the protection and repair of the marine ecosystem. Its green efficiency measurement can provide China with a means for a global low-carbon economy. From the ecological perspective of net carbon sink, this paper selects three indexes: input, expected output and unexpected output. The total carbon sink and carbon emissions are included in the evaluation index system of green efficiency of seaweed culture in China. The green efficiency of seaweed culture in China from 2008 to 2020 is calculated by the super-SBM model. Through the redundancy rate of input and output, the influencing factors of net carbon sink output of seaweed culture are put forward. According to the empirical calculation results and influencing factors of green efficiency, the countermeasures and suggestions for green seaweed culture in China under the dual-carbon target are put forward. The results showed that: (1) the net carbon sink and green efficiency level of seaweed culture in China showed an overall growth trend, and there was a lot of room for growth in economic and ecological benefits; (2) influenced by index factors and non-index factors such as marine resource economy and planning, there are differences in seaweed culture and green efficiency in the three major sea areas of China; (3) the indexes of green efficiency of seaweed culture in different study areas are different; and (4) the improvement of green efficiency can promote the Chinese seaweed culture industry. Green technology progress effect, structure effect, and input–output scale effect are the main influencing mechanisms of green efficiency of seaweed culture. It is suggested that in the future, we should optimize the structure of seaweed culture, innovate seaweed culture technology, improve carbon sink trading policy and strengthen the training of carbon sink talents. This will accelerate the realization of the goal of green and double carbon seaweed culture and promote the global low-carbon economy.

Greenhouse gas emissions and carbon budget estimation in constructed wetlands treating aquaculture tailwater: Insight from seasonal dynamics of dissolved organic matter and microbial community.

To achieve the goal of urban carbon dioxide emission reduction, how to increase carbon sequestration has become a top priority. The biological sink is mainly divided into green carbon sink and blue carbon sink. Coastal cities have two kinds of carbon sinks. There, the study of carbon sinks in coastal cities is the primary choice to cope with climate change. Therefore, this study chooses coastal cities with primary industries including agriculture, fishery, and forestry as the study subjects. The LMDI (Log-Mean Divisia Index) method and multiple regression prediction models were used to explore the low-carbon countermeasures which increase urban net carbon sink from the perspective of influencing factors and future potential. The study found that the average output value of employees in the primary industry is the main driving factor, and the change in the purchasing power of unit carbon sinks and the change in the proportion of employees in the primary industry have inhibited the increase in net carbon sinks. Projections based on the primary industry's output and afforestation area as independent variables show an overall upward trend in net carbon sinks, reaching 15.70 million tons of net carbon sinks in 2060, offsetting 10-20% of total carbon emissions in the same year. Based on the calculation results, this paper puts forward some corresponding countermeasures to increase carbon sinks. This paper provides a theoretical reference for the low-carbon development of coastal cities in China, and the strategies can be also expanded to other cities with similar resources around the world.

Based on the panel data of prefecture-level cities and above and provincial-level cities in the Yangtze River Economic Belt, respectively, this study measured the agricultural carbon emissions, carbon sinks, and carbon offset rates from 2006 to 2021 and analyzed their evolution characteristics. Based on the STIRPAT model and ridge regression analysis, this study identified the factors affecting agricultural carbon emissions in the 11 provinces and municipalities in the Yangtze River Economic Zone, combined them with the scenario analysis method to predict the agricultural carbon emissions under the baseline scenario in the period of 2022 to 2025, and analyzed the process of "carbon peaking." Simultaneously, this study predicted the agricultural carbon sinks of 11 provinces and cities from 2022 to 2025 and then speculated their agricultural "carbon neutral" process under the framework of agricultural carbon compensation rate, so as to summarize the effective paths for different provinces and cities to achieve agricultural "carbon peak and carbon neutral." The results showed that： ① Changes in agricultural carbon emissions in the Yangtze River Economic Zone during the observation period followed an inverted U-shape and peaked in 2015 at 33 312.65×104 tons. The fluctuation of agricultural carbon sinks was relatively small, with an overall upward trend. The upward trend of the agricultural carbon offset rate was obvious, but it still belonged to the "net carbon emission" region. ② Regional differences of agricultural carbon offsetting rate were prominent, and there was a polarization phenomenon, with "net carbon sink" cities significantly less than "net carbon emission" cities. ③ Shanghai, Zhejiang, and Sichuan reached the peak of agricultural carbon emissions in 2006, which Anhui and Chongqing reached in 2012, and the rest of the provinces and municipalities showed a clear upward trend. ④ Anhui, Chongqing, Sichuan, and Yunnan crossed the "agricultural carbon neutral line" and achieved agricultural carbon neutrality. Jiangsu was expected to achieve this in 2026-2030, whereas the remaining provinces and municipalities faced greater difficulties.

Agroforestry management has immense potential in enhancing forest carbon sequestration and mitigating climate change. Yet the impact and response mechanism of compound fertilization rates on carbon sinks in agroforestry systems remain ambiguous. This study aims to elucidate the impact of different compound fertilizer rates on soil greenhouse gas (GHG) emissions, vegetation and soil organic carbon (SOC) sinks, and to illustrate the differences in agroforestry systems' carbon sinks through a one-year positioning test across 12 plots, applying different compound fertilizer application rates (0 (CK), 400 (A1), 800 (A2), and 1600 (A3) kg ha-1). The study demonstrated that, after fertilization, the total GHG emissions of A1 decreased by 4.41%, whereas A2 and A3 increased their total GHG emissions by 17.13% and 72.23%, respectively. The vegetation carbon sequestration of A1, A2, and A3 increased by 18.04%, 26.75%, and 28.65%, respectively, and the soil organic carbon sequestration rose by 32.57%, 42.27% and 43.29%, respectively. To sum up, in contrast with CK, the ecosystem carbon sequestration climbed by 54.41%, 51.67%, and 0.90%, respectively. Our study suggests that rational fertilization can improve the carbon sink of the ecosystem and effectively ameliorate climate change.

Modelling the impact of future changes in climate, CO 2 concentration and land use on natural ecosystems and the terrestrial carbon sink

The influence of rapid urbanization and land use changes on terrestrial carbon sources/sinks in Guangzhou, China

Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Global Biogeochemical Cycles 25 (2011): GB1007, doi:10.1029/2010GB003838.

PDF HTML阅读 XML下载 导出引用 引用提醒 草地农业生态系统的碳平衡分析方法 DOI: 10.5846/stxb201507171503 作者: 作者单位: 兰州大学草地农业科技学院，草地农业生态系统国家重点实验室,兰州大学草地农业科技学院，草地农业生态系统国家重点实验室,兰州大学草地农业科技学院，草地农业生态系统国家重点实验室 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点基础研究发展计划资助项目（2014CB138706）；国家自然科学基金资助项目（31172249）；长江学者和创新团队发展计划资助项目（IRT13019）；国家科技支撑计划课题资助项目（2011BAD17B0203） Carbon balance analysis methods of grassland agro-ecosystems Author: Affiliation: The State Key Laboratory of Grassland Agroecosystems,College of Pastoral Agriculture Science and Technology,Lanzhou University,The State Key Laboratory of Grassland Agroecosystems,College of Pastoral Agriculture Science and Technology,Lanzhou University,The State Key Laboratory of Grassland Agroecosystems,College of Pastoral Agriculture Science and Technology,Lanzhou University;China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:根据草地农业生态系统的结构，它的碳平衡为4个生产层的碳平衡之和，也是3个界面的碳平衡之和，而某一生产层或者某一界面的碳平衡则是其固定、输入、排放和输出的碳之和。草地农业生态系统4个生产层的碳平衡分析方法定量重要生产环节的碳汇与碳源过程，便于草业生产改进碳汇管理；草地农业生态系统3个界面的碳平衡分析方法显示碳源和碳汇的发生机理，及其空间和数量关系，便于调控草业生产组分以增汇减排；但是，这两个方法不易区分碳的来源和去向，难以明确其利用效率。草地农业生态系统碳平衡分析的输入/输出法定量地指示碳的来源和去向，以及碳效率，计算简单，但是较为概括，不利于牧场尺度的草业碳汇管理。以中国祁连山甘肃马鹿牧场和澳大利亚塔斯玛尼亚奶牛牧场为例，用3种方法分析了两个牧场的碳平衡，结果表明，放牧管理的草业系统的主要碳源是休闲旅游、产品加工流通环节产生的温室气体，主要碳汇是草地和土壤中贮存的碳，好的草地管理可以增汇减排。 Abstract:According to the structures of grassland agro-ecosystems, their carbon balance represent the sum of the carbon balances of the four production levels, or the sum from its three interfaces. The carbon balance per production level or interface is the sum of the carbon that is taken up and lost through the different processes in that level or interface. The carbon balance analysis method based on four production levels can quantify which of the processes in the production are either a carbon sink or source. For example, carbon and nitrogen accumulation such as Carbon and Nitrogen sink, soil and water conservation are carbon sink process in Pre-plant production level. The grassland tourism hunting and so on, are the process of carbon source in Pre-plant production level. Photosynthesis and carbon and nitrogen assimilation of biological nitrogen fixation are the process of carbon sink in Plant production level. Greenhouse gases emission is the process of carbon source in Plant production level. The process of carbon sink and source in Animal production level are mostly Carbon fixation in animal product and greenhouse gases emission of ruminant. Carbon fixation in forage and animal products are the process of carbon sink in Post-biological production level. Processing and transport activities are the process of carbon source in Post-biological production level. This can subsequently facilitate improvements in the management of carbon sequestration in grassland production. Furthermore, the carbon balance analysis method based on three interfaces can determine the production mechanisms of carbon sinks and sources, as well as their spatial and quantitative relationships. This can contribute to regulating and controlling the carbon emissions from grassland agro-ecosystems. However, both methods cannot accurately quantify a grassland system's paths of carbon uptake and output, or its utilization efficiency. The carbon balance analysis by the balance between carbon input and output can quantify the pathway of carbon movement. This method is simple and more succinct; however, it is not applicable to farmland scale management of carbon sequestration. Considering a ranch in the Qilian Mountains, China, and a dairy farm in Tasmania, Australia, as examples, three methods were used for analyzing their carbon balances. The results showed that carbon emissions from tourism, product processing, and marketing accounted for the major portions of the total emissions from the grazing management system. Their main carbon sinks were carbon stored in the forage and the soil. Overall, optimal grassland management would benefit from adding carbon sinks and reducing carbon emissions. 参考文献 相似文献 引证文献