It is difficult to quantify and certify the greenhouse gas(GHG)emission reduction in the entire process of a project of carbon capture,utilization and storage(CCUS)-enhanced oil recovery(EOR).Under the methodological ...It is difficult to quantify and certify the greenhouse gas(GHG)emission reduction in the entire process of a project of carbon capture,utilization and storage(CCUS)-enhanced oil recovery(EOR).Under the methodological framework for GHG voluntary emission reduction project,the carbon emission reduction accounting method for CCUS-EOR project was established after examining the accounting boundaries in process links,the baseline emission and project emission accounting methods,and the emission and leakage quantification and prediction models,in order to provide a certification basis for the quantification of GHG emission reduction in the CCUS-EOR project.Based on the data of energy consumption,emission and leakage monitoring of the CCUS-EOR industrial demonstration project in Jilin Oilfield,the net emission reduction efficiency is determined to be about 91.1%at the current storage efficiency of 80%.The accounting and prediction of carbon emission reduction for CCUS-EOR projects with different concentrations and scales indicate that within the project accounting boundary,the certified net emission reduction efficiency of the low-concentration gas source CCUS-EOR projects represented by coal-fired power plants is about 37.1%,and the certified net emission reduction efficiency of the high-concentration gas source CCUS-EOR projects represented by natural gas hydrogen production is about 88.9%.The proposed method is applicable to the carbon emission reduction accounting for CCUS-EOR projects under multiple baseline scenarios during the certification period,which can provide decision-making basis for the planning and deployment of CCUS-EOR projects.展开更多
Climate change is the greatest environmental threat to humans and the planet in the 21st century.Global anthropogenic greenhouse gas emissions are one of the main causes of the increasing number of extreme climate eve...Climate change is the greatest environmental threat to humans and the planet in the 21st century.Global anthropogenic greenhouse gas emissions are one of the main causes of the increasing number of extreme climate events.Cumulative carbon dioxide(CO_(2))emissions showed a linear relationship with cumulative temperature rise since the pre-industrial stage,and this accounts for approximately 80%of the total anthropogenic greenhouse gases.Therefore,accurate and reliable carbon emission data are the foundation and scientific basis for most emission reduction policymaking and target setting.Currently,China has made clear the ambitious goal of achieving the peak of carbon emissions by 2030 and achieving carbon neutrality by 2060.The development of a finer-grained spatiotemporal carbon emission database is urgently needed to achieve more accurate carbon emission monitoring for continuous implementation and the iterative improvement of emission reduction policies.Near-real-time carbon emission monitoring is not only a major national demand but also a scientific question at the frontier of this discipline.This article reviews existing annual-based carbon accounting methods,with a focus on the newly developed real-time carbon emission technology and its current application trends.We also present a framework for the latest near-real-time carbon emission accounting technology that can be widely used.The development of relevant data and methods will provide strong database support to the policymaking for China’s“carbon neutrality”strategy.Finally,this article provides an outlook on the future of real-time carbon emission monitoring technology.展开更多
Green eco-district planning and construction occupies a very important position in China's future low carbon urbanization roadmap because the experience gained through practice will provide cities with a technical...Green eco-district planning and construction occupies a very important position in China's future low carbon urbanization roadmap because the experience gained through practice will provide cities with a technical pathway to manage climate change and reduce carbon emissions. However, during the current preparation and implementation stage of the green eco-district plans, both the planning management departments and planning design institutes are faced with the problem of how to quantify the greenhouse gases(GHG) emissions, especially the CO_2 emissions, when approval decisions are to be made. Aiming at setting up a carbon accounting protocol within the statutory framework of China's green eco-district planning and construction management system, this paper argues that it is important to incorporate the GHG emission inventory into the statutory regulatory planning system, and discusses the technical issues and coping measures for assessing carbon emissions at the district level. It proposes to refine the Activity Data(AD) and Emission Factors(EF) in the current China's National GHG Inventory and set up the urban district carbon accounting protocol based on nine sectors. These nine emission accounting sectors are established according to the key policy and function as defined in the statutory local regulatory plans under the present planning system in Chinese cities. Taking planning and construction management at the district level as a platform to control carbon emissions, it develops an initial carbon accounting protocol suitable for China's green eco-districts which can be applied in both the existing and planned urban areas, and be integrated into the decision making process of the local planning process.展开更多
Introduction:Research has shown the negative impacts of climate change on the economy and how the state of the environment has been a complex global challenge.Prior studies have suggested immediate actions to avoid an...Introduction:Research has shown the negative impacts of climate change on the economy and how the state of the environment has been a complex global challenge.Prior studies have suggested immediate actions to avoid any unforeseen circumstances for all living things on Earth.Previous research has also supported all kinds of sustainability efforts as resolutions to address the deterioration of climate change caused by business activities.Originality:There is a need for companies to start acting and assigning employees to mitigate carbon emitted by corporations.This study is motivated by the lack of empirical evidence that examines how corporate carbon governance influences better carbon performance of organizations and authorizes organizations to implement and embed carbon accounting.Objective:This study used evidence from Malaysia to explore this subject matter and examined the association between carbon governance and carbon performance of corporations.The research also investigated the mediation effect of carbon accounting with respect to carbon governance and carbon performance.Findings:It is revealed that carbon governance had no significant influence on an organization’s carbon performance although carbon accounting implementation positively influenced carbon performance.The findings imply that despite its insignificance,carbon accounting remains a vital matter to be deployed by organizations for better carbon emission mitigation.展开更多
Increasing the efficiency and proportion of photovoltaic power generation installations is one of the best ways to reduce both CO_(2) emissions and reliance on fossil-fuel-based power supplies.Solar energy is a clean ...Increasing the efficiency and proportion of photovoltaic power generation installations is one of the best ways to reduce both CO_(2) emissions and reliance on fossil-fuel-based power supplies.Solar energy is a clean and renewable power source with excellent potential for further development and utilization.In 2021,the global solar installed capacity was about 749.7 GW.Establishing correlations between solar power generation,standard coal equivalent,carbon sinks,and green sinks is crucial.However,there have been few reports about correlations between the efficiency of tracking solar photovoltaic panels and the above parameters.This paper calculates the increased power generation achievable through the use of tracking photovoltaic panels compared with traditional fixed panels and establishes relationships between power generation,standard coal equivalent,and carbon sinks,providing a basis for attempts to reduce reliance on carbon-based fuels.The calculations show that power generation efficiency can be improved by about 26.12%by enabling solar panels to track the sun's rays during the day and from season to season.Through the use of this improved technology,global CO_(2) emissions can be reduced by 183.63 Mt,and the standard coal equivalent can be reduced by 73.67 Mt yearly.Carbon capture is worth approximately EUR 15.48 billion,and carbon accounting analysis plays a vital role in carbon trading.展开更多
Addressing climate change has become a common issue around the world in the 21st century and equally an important mission in Chinese forestry.Understanding the development of monitoring and assessment of forest biomas...Addressing climate change has become a common issue around the world in the 21st century and equally an important mission in Chinese forestry.Understanding the development of monitoring and assessment of forest biomass and carbon storage in China is important for promoting the evaluation of forest carbon sequestration capacity of China.The author conducts a systematic analysis of domestic publications addressing"monitoring and assessment of forest biomass and carbon storage"in order to understand the development trends,describes the brief history through three stages,and gives the situation of new development.Towards the end of the 20th century,a large number of papers on biomass and productivity of the major forest types in China had been published,covering the exploration and efforts of more than 20 years,while investigations into assessment of forest carbon storage had barely begun.Based on the data of the 7th and 8th National Forest Inventories,forest biomass and carbon storage of the entire country were assessed using individual tree biomass models and carbon conversion factors of major tree species,both previously published and newly developed.Accompanying the implementation of the 8th National Forest Inventory,a program of individual tree biomass modeling for major tree species in China was carried out simultaneously.By means of thematic research on classification of modeling populations,as well as procedures for collecting samples and methodology for biomass modeling,two technical regulations on sample collection and model construction were published as ministerial standards for application.Requests for approval of individual tree biomass models and carbon accounting parameters of major tree species have been issued for approval as ministerial standards.With the improvement of biomass models and carbon accounting parameters,thematic assessment of forest biomass and carbon storage will be gradually changed into a general monitoring of forest biomass and carbon storage,in order to realize their dynamic monitoring in national forest inventories.Strengthening the analysis and assessment of spatial distribution patterns of forest biomass and carbon storage through application of remote sensing techniques and geostatistical approaches will also be one of the major directions of development in the near future.展开更多
Grassland is one of the largest terrestrial biomes,providing critical ecosystem services such as food production,biodiversity conservation,and climate change mitigation.Global climate change and land-use intensificati...Grassland is one of the largest terrestrial biomes,providing critical ecosystem services such as food production,biodiversity conservation,and climate change mitigation.Global climate change and land-use intensification have been causing grassland degradation and desertification worldwide.As one of the primary medium for ecosystem energy flow and biogeochemical cycling,grassland carbon(C)cycling is the most fundamental process for maintaining ecosystem services.In this review,we first summarize recent advances in our understanding of the mechanisms underpinning spatial and temporal patterns of the grassland C cycle,discuss the importance of grasslands in regulating inter-and intra-annual variations in global C fluxes,and explore the previously unappreciated complexity in abiotic processes controlling the grassland C balance,including soil inorganic C accumulation,photochemical and thermal degradation,and wind erosion.We also discuss how climate and land-use changes could alter the grassland C balance by modifying the water budget,nutrient cycling and additional plant and soil processes.Further,we examine why and how increasing aridity and improper land use may induce significant losses in grassland C stocks.Finally,we identify several priorities for future grassland C research,including improving understanding of abiotic processes in the grassland C cycle,strengthening monitoring of grassland C dynamics by integrating ground inventory,flux monitoring,and modern remote sensing techniques,and selecting appropriate plant species combinations with suitable traits and strong resistance to climate fluctuations,which would help design sustainable grassland restoration strategies in a changing climate.展开更多
Built-up area(BUA)significantly contributes to global greenhouse gas emissions,making strategic spatial planning crucial for carbon emission control.Given the diverse land use patterns and carbon emission sources in B...Built-up area(BUA)significantly contributes to global greenhouse gas emissions,making strategic spatial planning crucial for carbon emission control.Given the diverse land use patterns and carbon emission sources in BUAs,this study proposed a land-based strategy system for carbon emission assessment and optimization.A three-step method was devised to create a planner-friendly tool for implementing the system,which involves carbon emission intensity calculation based on current land use,spatial illustration of carbon emission intensities based on land use planning,and planning program optimization and emission reduction effect assessment.The method was applied to the central urban area of Changxing County(Zhejiang)in China.The results showed that the structures and emission intensities of urban land use substantially influenced the overall carbon emissions in the central urban area.Our comprehensive land use optimization strategies reduced the overall carbon emissions of the central urban area by 36.9%when compared to the original planning program.The Monte Carlo simulation indicated that land use structure optimization and emission intensity control measures could reduce carbon emission rate by 5.20%to 18.28%,and 18.44%to 31.67%,respectively.The results underlined the importance of making specific adjustments to land use structure and implementing intensity control measures for effective carbon reduction.In conclusion,this study offers methods and insights for urban planners in creating sustainable and low-carbon urban spaces.展开更多
Estimation of soil organic carbon (SOC) pools and fluxes bears large uncertainties because SOC stocks vary greatly over geographical space and through time. Although development of the U.S. Soil Survey Geographic Da...Estimation of soil organic carbon (SOC) pools and fluxes bears large uncertainties because SOC stocks vary greatly over geographical space and through time. Although development of the U.S. Soil Survey Geographic Database (SSURGO), currently the most detailed level with a map scale ranging from 1:12 000 to 1:63 360, has involved substantial government funds and coordinated network efforts, very few studies have utilized it for soil carbon assessment at the large landscape scale. The objectives of this study were to 1) compare estimates in soil organic matter among SSURGO, the State Soil Geographic Database (STATSGO), and referenced field measurements at the soil map unit; 2) examine the influence of missing data on SOC estimation by SSURGO and STATSGO; 3) quantify spatial differences in SOC estimation between SSURGO and STATSCO, specifically for the state of Louisiana; and 4) assess scale effects on soil organic carbon density (SOCD) estimates from a soil map unit to a watershed and a river basin scale. SOC was estimated using soil attributes of SSURGO and STATSGO including soil organic matter (SOM) content, soil layer depth, and bulk density. Paired t-test, correlation, and regression analyses were performed to investigate various relations of SOC and SOM among the datasets. There were positive relations of SOC estimates between SSURGO and STATSGO at the soil map unit (R2 = 0.56, n = 86, t = 1.65, P = 0.102; depth: 30 cm). However, the SOC estimated by STATSGO were 9%, 33% and 36~ lower for the upper 30-cm, the upper l-m, and the maximal depth (up to 2.75 m) soils, respectively, than those from SSURGO. The difference tended to increase as the spatial scale changes from the soil map unit to the watershed and river basin scales. Compared with the referenced field measurements, the estimates in SOM by SSURGO showed a closer match than those of STATSCO, indicating that the former was more accurate than the latter in SOC estimation, both in spatial and temporal resolutions. Further applications of SSURGO in SOC estimation for the entire United States could improve the accuracy of soil carbon accounting in regional and national carbon balances.展开更多
Aims Forest biomass carbon(C)stocks are usually estimated by multiplying biomass by a C conversion factor,i.e.C concentration.Thus,tree C concentration is crucial to the assessments of forest C cycles.As stems contrib...Aims Forest biomass carbon(C)stocks are usually estimated by multiplying biomass by a C conversion factor,i.e.C concentration.Thus,tree C concentration is crucial to the assessments of forest C cycles.As stems contribute to the large fraction of tree biomass,the canonical value of 50%or other simplified values of stem C concentration are widely used to represent the values of tree C concentration in the estimations of forest C stocks at different scales.However,C concentration variations between tree organs and within tree size and their impacts on forest C stocks are still unclear.Methods We conducted a global analysis of organ C concentration in age-specific trees based on 576 records of tree age,size(diameter at breast height and biomass)and C concentration data to evaluate the relationships between organ C concentrations and the changes of stem C concentration with tree age and size.Important Findings Tree C concentration varied significantly with organs.Stem C concentration of trees was significantly correlated with that of other tree organs,except for barks and reproductive organs.The stem C concentration increased significantly with tree size and age,which contributed to the increases in C contents of stems and trees.Using the C concentration in stems to represent the C concentrations of other organs and the whole tree could produce considerable errors in the estimations of forest C stocks(−8.6%to 25.6%and−2.5%to 5.9%,respectively).Our findings suggest that tree C accumulation in forests is related to the size-and age-dependent increases in stem C concentration and using specific C concentration values of tree organs can improve the estimations of forest C stocks.展开更多
By elaborating the functions and effects of forestry in mitigating climate change, introducing the concepts and significance of forest carbon sink, forestry carbon sequestration, and carbon sequestration forestry, and...By elaborating the functions and effects of forestry in mitigating climate change, introducing the concepts and significance of forest carbon sink, forestry carbon sequestration, and carbon sequestration forestry, and summarizing the practices of carbon sequestration forestry in China, the paper came up with the outline for strengthening the management of carbon sequestration forestry, i.e. implementing the Climate Change Forestry Action Plan, reinforcing the accounting and monitoring of national forest carbon sink and the management of the qualification of carbon sink accounting project teams, and carrying out pilot researches on low-carbon forestry for achieving low-carbon economy. The study was aimed to ensure that the forestry sector can fulfill its responsibility to mitigate climate change and contribute to mitigating the global warming.展开更多
Globally,the reduction of excessive N losses and greenhouse gas(GHG)emissions is a central environmental challenge in the 21 century.China has huge associated emissions during both production and land application phas...Globally,the reduction of excessive N losses and greenhouse gas(GHG)emissions is a central environmental challenge in the 21 century.China has huge associated emissions during both production and land application phases.In addition,70%of N fertilizer in China is produced and land applied as urea,which has high associated emissions.This study utilized life cycle analysis to compare the carbon emission capacity of different N fertilizers and quantified GHG emissions from different N fertilizer chains within China.This enabled a new innovative reform model to be proposed,which aims to decrease the carbon footprint and increase the net ecosystem carbon budget of China.The results showed that the carbon footprint of the N fertilizer industry was about 229 Tg·yr^(-1)CO_(2)-eq in 2020.Through changes away from urea through the production and land application of a mix of newly emerging fertilizers,liquid fertilizers and standard fertilizer reductions to 174–182 Tg·yr^(-1)CO_(2)-eq.Through the upgrading of mineral N fertilizer production technology,the carbon footprint of N fertilizer chain can be reduced by34.8 Tg·yr^(-1)CO_(2)-eq.Such reductions would reduce China's total GHG emissions to 140–147 Tg·yr^(-1)CO_(2)-eq.展开更多
基金Supported by the PetroChina Science and Technology Project (2021ZZ01-06,2021DJ1101)。
文摘It is difficult to quantify and certify the greenhouse gas(GHG)emission reduction in the entire process of a project of carbon capture,utilization and storage(CCUS)-enhanced oil recovery(EOR).Under the methodological framework for GHG voluntary emission reduction project,the carbon emission reduction accounting method for CCUS-EOR project was established after examining the accounting boundaries in process links,the baseline emission and project emission accounting methods,and the emission and leakage quantification and prediction models,in order to provide a certification basis for the quantification of GHG emission reduction in the CCUS-EOR project.Based on the data of energy consumption,emission and leakage monitoring of the CCUS-EOR industrial demonstration project in Jilin Oilfield,the net emission reduction efficiency is determined to be about 91.1%at the current storage efficiency of 80%.The accounting and prediction of carbon emission reduction for CCUS-EOR projects with different concentrations and scales indicate that within the project accounting boundary,the certified net emission reduction efficiency of the low-concentration gas source CCUS-EOR projects represented by coal-fired power plants is about 37.1%,and the certified net emission reduction efficiency of the high-concentration gas source CCUS-EOR projects represented by natural gas hydrogen production is about 88.9%.The proposed method is applicable to the carbon emission reduction accounting for CCUS-EOR projects under multiple baseline scenarios during the certification period,which can provide decision-making basis for the planning and deployment of CCUS-EOR projects.
基金financially supported by the National Natural Science Foundation of China (71874097 and 41921005)Beijing Natural Science Foundation (JQ19032)+1 种基金the Qiu Shi Science & Technologies Foundationthe Shenzhen Municipal Science and Technology Commission College Stability Support Project (WDZC20200819173345002)
文摘Climate change is the greatest environmental threat to humans and the planet in the 21st century.Global anthropogenic greenhouse gas emissions are one of the main causes of the increasing number of extreme climate events.Cumulative carbon dioxide(CO_(2))emissions showed a linear relationship with cumulative temperature rise since the pre-industrial stage,and this accounts for approximately 80%of the total anthropogenic greenhouse gases.Therefore,accurate and reliable carbon emission data are the foundation and scientific basis for most emission reduction policymaking and target setting.Currently,China has made clear the ambitious goal of achieving the peak of carbon emissions by 2030 and achieving carbon neutrality by 2060.The development of a finer-grained spatiotemporal carbon emission database is urgently needed to achieve more accurate carbon emission monitoring for continuous implementation and the iterative improvement of emission reduction policies.Near-real-time carbon emission monitoring is not only a major national demand but also a scientific question at the frontier of this discipline.This article reviews existing annual-based carbon accounting methods,with a focus on the newly developed real-time carbon emission technology and its current application trends.We also present a framework for the latest near-real-time carbon emission accounting technology that can be widely used.The development of relevant data and methods will provide strong database support to the policymaking for China’s“carbon neutrality”strategy.Finally,this article provides an outlook on the future of real-time carbon emission monitoring technology.
文摘Green eco-district planning and construction occupies a very important position in China's future low carbon urbanization roadmap because the experience gained through practice will provide cities with a technical pathway to manage climate change and reduce carbon emissions. However, during the current preparation and implementation stage of the green eco-district plans, both the planning management departments and planning design institutes are faced with the problem of how to quantify the greenhouse gases(GHG) emissions, especially the CO_2 emissions, when approval decisions are to be made. Aiming at setting up a carbon accounting protocol within the statutory framework of China's green eco-district planning and construction management system, this paper argues that it is important to incorporate the GHG emission inventory into the statutory regulatory planning system, and discusses the technical issues and coping measures for assessing carbon emissions at the district level. It proposes to refine the Activity Data(AD) and Emission Factors(EF) in the current China's National GHG Inventory and set up the urban district carbon accounting protocol based on nine sectors. These nine emission accounting sectors are established according to the key policy and function as defined in the statutory local regulatory plans under the present planning system in Chinese cities. Taking planning and construction management at the district level as a platform to control carbon emissions, it develops an initial carbon accounting protocol suitable for China's green eco-districts which can be applied in both the existing and planned urban areas, and be integrated into the decision making process of the local planning process.
文摘Introduction:Research has shown the negative impacts of climate change on the economy and how the state of the environment has been a complex global challenge.Prior studies have suggested immediate actions to avoid any unforeseen circumstances for all living things on Earth.Previous research has also supported all kinds of sustainability efforts as resolutions to address the deterioration of climate change caused by business activities.Originality:There is a need for companies to start acting and assigning employees to mitigate carbon emitted by corporations.This study is motivated by the lack of empirical evidence that examines how corporate carbon governance influences better carbon performance of organizations and authorizes organizations to implement and embed carbon accounting.Objective:This study used evidence from Malaysia to explore this subject matter and examined the association between carbon governance and carbon performance of corporations.The research also investigated the mediation effect of carbon accounting with respect to carbon governance and carbon performance.Findings:It is revealed that carbon governance had no significant influence on an organization’s carbon performance although carbon accounting implementation positively influenced carbon performance.The findings imply that despite its insignificance,carbon accounting remains a vital matter to be deployed by organizations for better carbon emission mitigation.
文摘Increasing the efficiency and proportion of photovoltaic power generation installations is one of the best ways to reduce both CO_(2) emissions and reliance on fossil-fuel-based power supplies.Solar energy is a clean and renewable power source with excellent potential for further development and utilization.In 2021,the global solar installed capacity was about 749.7 GW.Establishing correlations between solar power generation,standard coal equivalent,carbon sinks,and green sinks is crucial.However,there have been few reports about correlations between the efficiency of tracking solar photovoltaic panels and the above parameters.This paper calculates the increased power generation achievable through the use of tracking photovoltaic panels compared with traditional fixed panels and establishes relationships between power generation,standard coal equivalent,and carbon sinks,providing a basis for attempts to reduce reliance on carbon-based fuels.The calculations show that power generation efficiency can be improved by about 26.12%by enabling solar panels to track the sun's rays during the day and from season to season.Through the use of this improved technology,global CO_(2) emissions can be reduced by 183.63 Mt,and the standard coal equivalent can be reduced by 73.67 Mt yearly.Carbon capture is worth approximately EUR 15.48 billion,and carbon accounting analysis plays a vital role in carbon trading.
基金funded by the State Forestry Administration of China
文摘Addressing climate change has become a common issue around the world in the 21st century and equally an important mission in Chinese forestry.Understanding the development of monitoring and assessment of forest biomass and carbon storage in China is important for promoting the evaluation of forest carbon sequestration capacity of China.The author conducts a systematic analysis of domestic publications addressing"monitoring and assessment of forest biomass and carbon storage"in order to understand the development trends,describes the brief history through three stages,and gives the situation of new development.Towards the end of the 20th century,a large number of papers on biomass and productivity of the major forest types in China had been published,covering the exploration and efforts of more than 20 years,while investigations into assessment of forest carbon storage had barely begun.Based on the data of the 7th and 8th National Forest Inventories,forest biomass and carbon storage of the entire country were assessed using individual tree biomass models and carbon conversion factors of major tree species,both previously published and newly developed.Accompanying the implementation of the 8th National Forest Inventory,a program of individual tree biomass modeling for major tree species in China was carried out simultaneously.By means of thematic research on classification of modeling populations,as well as procedures for collecting samples and methodology for biomass modeling,two technical regulations on sample collection and model construction were published as ministerial standards for application.Requests for approval of individual tree biomass models and carbon accounting parameters of major tree species have been issued for approval as ministerial standards.With the improvement of biomass models and carbon accounting parameters,thematic assessment of forest biomass and carbon storage will be gradually changed into a general monitoring of forest biomass and carbon storage,in order to realize their dynamic monitoring in national forest inventories.Strengthening the analysis and assessment of spatial distribution patterns of forest biomass and carbon storage through application of remote sensing techniques and geostatistical approaches will also be one of the major directions of development in the near future.
基金supported by the National Natural Science Foundation of China (32125025 and 31988102)the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA23080301 and XDA26010303)JMG acknowledges the support of the Israel Science Foundation (1796/19).
文摘Grassland is one of the largest terrestrial biomes,providing critical ecosystem services such as food production,biodiversity conservation,and climate change mitigation.Global climate change and land-use intensification have been causing grassland degradation and desertification worldwide.As one of the primary medium for ecosystem energy flow and biogeochemical cycling,grassland carbon(C)cycling is the most fundamental process for maintaining ecosystem services.In this review,we first summarize recent advances in our understanding of the mechanisms underpinning spatial and temporal patterns of the grassland C cycle,discuss the importance of grasslands in regulating inter-and intra-annual variations in global C fluxes,and explore the previously unappreciated complexity in abiotic processes controlling the grassland C balance,including soil inorganic C accumulation,photochemical and thermal degradation,and wind erosion.We also discuss how climate and land-use changes could alter the grassland C balance by modifying the water budget,nutrient cycling and additional plant and soil processes.Further,we examine why and how increasing aridity and improper land use may induce significant losses in grassland C stocks.Finally,we identify several priorities for future grassland C research,including improving understanding of abiotic processes in the grassland C cycle,strengthening monitoring of grassland C dynamics by integrating ground inventory,flux monitoring,and modern remote sensing techniques,and selecting appropriate plant species combinations with suitable traits and strong resistance to climate fluctuations,which would help design sustainable grassland restoration strategies in a changing climate.
文摘Built-up area(BUA)significantly contributes to global greenhouse gas emissions,making strategic spatial planning crucial for carbon emission control.Given the diverse land use patterns and carbon emission sources in BUAs,this study proposed a land-based strategy system for carbon emission assessment and optimization.A three-step method was devised to create a planner-friendly tool for implementing the system,which involves carbon emission intensity calculation based on current land use,spatial illustration of carbon emission intensities based on land use planning,and planning program optimization and emission reduction effect assessment.The method was applied to the central urban area of Changxing County(Zhejiang)in China.The results showed that the structures and emission intensities of urban land use substantially influenced the overall carbon emissions in the central urban area.Our comprehensive land use optimization strategies reduced the overall carbon emissions of the central urban area by 36.9%when compared to the original planning program.The Monte Carlo simulation indicated that land use structure optimization and emission intensity control measures could reduce carbon emission rate by 5.20%to 18.28%,and 18.44%to 31.67%,respectively.The results underlined the importance of making specific adjustments to land use structure and implementing intensity control measures for effective carbon reduction.In conclusion,this study offers methods and insights for urban planners in creating sustainable and low-carbon urban spaces.
基金Supported by the U.S. Louisiana Board of Regents (No. LEQSF (2004-2007)-RD-A-04)
文摘Estimation of soil organic carbon (SOC) pools and fluxes bears large uncertainties because SOC stocks vary greatly over geographical space and through time. Although development of the U.S. Soil Survey Geographic Database (SSURGO), currently the most detailed level with a map scale ranging from 1:12 000 to 1:63 360, has involved substantial government funds and coordinated network efforts, very few studies have utilized it for soil carbon assessment at the large landscape scale. The objectives of this study were to 1) compare estimates in soil organic matter among SSURGO, the State Soil Geographic Database (STATSGO), and referenced field measurements at the soil map unit; 2) examine the influence of missing data on SOC estimation by SSURGO and STATSGO; 3) quantify spatial differences in SOC estimation between SSURGO and STATSCO, specifically for the state of Louisiana; and 4) assess scale effects on soil organic carbon density (SOCD) estimates from a soil map unit to a watershed and a river basin scale. SOC was estimated using soil attributes of SSURGO and STATSGO including soil organic matter (SOM) content, soil layer depth, and bulk density. Paired t-test, correlation, and regression analyses were performed to investigate various relations of SOC and SOM among the datasets. There were positive relations of SOC estimates between SSURGO and STATSGO at the soil map unit (R2 = 0.56, n = 86, t = 1.65, P = 0.102; depth: 30 cm). However, the SOC estimated by STATSGO were 9%, 33% and 36~ lower for the upper 30-cm, the upper l-m, and the maximal depth (up to 2.75 m) soils, respectively, than those from SSURGO. The difference tended to increase as the spatial scale changes from the soil map unit to the watershed and river basin scales. Compared with the referenced field measurements, the estimates in SOM by SSURGO showed a closer match than those of STATSCO, indicating that the former was more accurate than the latter in SOC estimation, both in spatial and temporal resolutions. Further applications of SSURGO in SOC estimation for the entire United States could improve the accuracy of soil carbon accounting in regional and national carbon balances.
基金supported by the National Key Research and Development Program of China(grant no.2017YFC0503903)National Natural Science Foundation of China(grant no.31621091).
文摘Aims Forest biomass carbon(C)stocks are usually estimated by multiplying biomass by a C conversion factor,i.e.C concentration.Thus,tree C concentration is crucial to the assessments of forest C cycles.As stems contribute to the large fraction of tree biomass,the canonical value of 50%or other simplified values of stem C concentration are widely used to represent the values of tree C concentration in the estimations of forest C stocks at different scales.However,C concentration variations between tree organs and within tree size and their impacts on forest C stocks are still unclear.Methods We conducted a global analysis of organ C concentration in age-specific trees based on 576 records of tree age,size(diameter at breast height and biomass)and C concentration data to evaluate the relationships between organ C concentrations and the changes of stem C concentration with tree age and size.Important Findings Tree C concentration varied significantly with organs.Stem C concentration of trees was significantly correlated with that of other tree organs,except for barks and reproductive organs.The stem C concentration increased significantly with tree size and age,which contributed to the increases in C contents of stems and trees.Using the C concentration in stems to represent the C concentrations of other organs and the whole tree could produce considerable errors in the estimations of forest C stocks(−8.6%to 25.6%and−2.5%to 5.9%,respectively).Our findings suggest that tree C accumulation in forests is related to the size-and age-dependent increases in stem C concentration and using specific C concentration values of tree organs can improve the estimations of forest C stocks.
文摘By elaborating the functions and effects of forestry in mitigating climate change, introducing the concepts and significance of forest carbon sink, forestry carbon sequestration, and carbon sequestration forestry, and summarizing the practices of carbon sequestration forestry in China, the paper came up with the outline for strengthening the management of carbon sequestration forestry, i.e. implementing the Climate Change Forestry Action Plan, reinforcing the accounting and monitoring of national forest carbon sink and the management of the qualification of carbon sink accounting project teams, and carrying out pilot researches on low-carbon forestry for achieving low-carbon economy. The study was aimed to ensure that the forestry sector can fulfill its responsibility to mitigate climate change and contribute to mitigating the global warming.
基金supported by the“Green Intelligent Fertilizer Products”strategic research program funded by the CNSG Anhui Hong Sifang Co.,Ltd.Inhibitors Design and Development Project funded by the Wuwei Jincang Bioscience Co.,Ltd.Quzhou Agricultural Carbon Neutral Construction Project funded by the Quzhou Municipal Bureau of Agriculture and Rural Affairs。
文摘Globally,the reduction of excessive N losses and greenhouse gas(GHG)emissions is a central environmental challenge in the 21 century.China has huge associated emissions during both production and land application phases.In addition,70%of N fertilizer in China is produced and land applied as urea,which has high associated emissions.This study utilized life cycle analysis to compare the carbon emission capacity of different N fertilizers and quantified GHG emissions from different N fertilizer chains within China.This enabled a new innovative reform model to be proposed,which aims to decrease the carbon footprint and increase the net ecosystem carbon budget of China.The results showed that the carbon footprint of the N fertilizer industry was about 229 Tg·yr^(-1)CO_(2)-eq in 2020.Through changes away from urea through the production and land application of a mix of newly emerging fertilizers,liquid fertilizers and standard fertilizer reductions to 174–182 Tg·yr^(-1)CO_(2)-eq.Through the upgrading of mineral N fertilizer production technology,the carbon footprint of N fertilizer chain can be reduced by34.8 Tg·yr^(-1)CO_(2)-eq.Such reductions would reduce China's total GHG emissions to 140–147 Tg·yr^(-1)CO_(2)-eq.