Rail transit plays a key role in mitigating transportation system carbon emissions.Accurate measurement of urban rail transit carbon emission can help quantify the contribution of urban rail transit towards urban tran...Rail transit plays a key role in mitigating transportation system carbon emissions.Accurate measurement of urban rail transit carbon emission can help quantify the contribution of urban rail transit towards urban transportation carbon emission reduction.Since the whole life cycle of urban rail transit carbon emission measurement involves a wide range of aspects,a systematic framework model is required for analysis.This research reviews the existing studies on carbon emission of urban rail transit.First,the characteristics of urban rail transit carbon emission were determined and the complexity of carbon emission measurement was analyzed.Then,the urban rail transit carbon emission measurement models were compared and analyzed in terms of the selection of research boundaries,the types of greenhouse gas(GHG)emissions calculation,and the accuracy of the measurement.Following that,an intelligent station was introduced to analyze the practical application of digital collaboration technology and energy-saving and carbon-reducing system platforms for rail transit.Finally,the urgent problems and future research directions at this stage were discussed.This research presents the necessity of establishing a dynamic carbon emission factor library and the important development trend of system integration of carbon emission measurement and digital system technology.展开更多
Reducing agricultural carbon emissions is important to enable carbon emission peaking by 2030 in China.However,China's transformation towards large-scale farming brings uncertainties to carbon emission reduction.T...Reducing agricultural carbon emissions is important to enable carbon emission peaking by 2030 in China.However,China's transformation towards large-scale farming brings uncertainties to carbon emission reduction.This study quantifies the carbon emissions from cropping based on life cycle assessment and estimates the effects of farm size on carbon emissions using a fixed effects model.Furthermore,the variations of the carbon emissions from cropping driven by the changes in farm size in future years are projected through scenario analysis.Results demonstrate an inverted U-shaped change in total carbon emission from cropping as farm size increases,which is dominated by the changes in the carbon emission from fertilizer.Projections illustrate that large-scale farming transformation will postpone the peak year of total carbon emission from cropping until 2048 if the change in farm size follows a historical trend,although it is conducive to reducing total carbon emission in the long run.The findings indicate that environmental regulations to reduce fertilizer usages should be strengthened for carbon emission abatement in the early stage of large-scale farming transformation,which are also informative to other developing countries with small farm size.展开更多
Reaching carbon neutrality will require investment on an unprecedented scale.Here we suggest that there is an underappreciated opportunity to leverage public funds to mobilize private capital in support of these aims....Reaching carbon neutrality will require investment on an unprecedented scale.Here we suggest that there is an underappreciated opportunity to leverage public funds to mobilize private capital in support of these aims.We illustrate the point using examples from public transit.Although the fuelling energy requirements of public fleets represent a small fraction of the eventual total demand across the transportation sector,the predictable and long-term nature of the refuelling profiles can reduce the financing risk.With appropriate coordination across the energy supply chain,near-term investments can be used to support scale-up of wider efforts to decarbonize the transportation sector and electric grid.We present two examples from California-one related to overnight power for battery electric bus charging and the other related to medium-scale supply chains for zero-carbon hydrogen production-to illustrate how this might be achieved.展开更多
基金supported by Beijing Natural Science Foundation(J210001)Natural Science Foundation of Hebei Province(E2021210142)Tianjin Natural Science Foundation(21JCZXJC00160).
文摘Rail transit plays a key role in mitigating transportation system carbon emissions.Accurate measurement of urban rail transit carbon emission can help quantify the contribution of urban rail transit towards urban transportation carbon emission reduction.Since the whole life cycle of urban rail transit carbon emission measurement involves a wide range of aspects,a systematic framework model is required for analysis.This research reviews the existing studies on carbon emission of urban rail transit.First,the characteristics of urban rail transit carbon emission were determined and the complexity of carbon emission measurement was analyzed.Then,the urban rail transit carbon emission measurement models were compared and analyzed in terms of the selection of research boundaries,the types of greenhouse gas(GHG)emissions calculation,and the accuracy of the measurement.Following that,an intelligent station was introduced to analyze the practical application of digital collaboration technology and energy-saving and carbon-reducing system platforms for rail transit.Finally,the urgent problems and future research directions at this stage were discussed.This research presents the necessity of establishing a dynamic carbon emission factor library and the important development trend of system integration of carbon emission measurement and digital system technology.
基金the Natural Science Foundation of China–Bill&Melinda Gates Foundation Joint Agricultural Research Project(NSFC–BMGF72261147758)+2 种基金the National Social Science Foundation of Chinathe China Resource,Environmental and Development Research Institute,Nanjing Agricultural University,Chinathe Research Funding Project of Anhui Agricultural University,China(rc402108)。
文摘Reducing agricultural carbon emissions is important to enable carbon emission peaking by 2030 in China.However,China's transformation towards large-scale farming brings uncertainties to carbon emission reduction.This study quantifies the carbon emissions from cropping based on life cycle assessment and estimates the effects of farm size on carbon emissions using a fixed effects model.Furthermore,the variations of the carbon emissions from cropping driven by the changes in farm size in future years are projected through scenario analysis.Results demonstrate an inverted U-shaped change in total carbon emission from cropping as farm size increases,which is dominated by the changes in the carbon emission from fertilizer.Projections illustrate that large-scale farming transformation will postpone the peak year of total carbon emission from cropping until 2048 if the change in farm size follows a historical trend,although it is conducive to reducing total carbon emission in the long run.The findings indicate that environmental regulations to reduce fertilizer usages should be strengthened for carbon emission abatement in the early stage of large-scale farming transformation,which are also informative to other developing countries with small farm size.
文摘Reaching carbon neutrality will require investment on an unprecedented scale.Here we suggest that there is an underappreciated opportunity to leverage public funds to mobilize private capital in support of these aims.We illustrate the point using examples from public transit.Although the fuelling energy requirements of public fleets represent a small fraction of the eventual total demand across the transportation sector,the predictable and long-term nature of the refuelling profiles can reduce the financing risk.With appropriate coordination across the energy supply chain,near-term investments can be used to support scale-up of wider efforts to decarbonize the transportation sector and electric grid.We present two examples from California-one related to overnight power for battery electric bus charging and the other related to medium-scale supply chains for zero-carbon hydrogen production-to illustrate how this might be achieved.
