Inventorying And Mapping The CO₂-e Emissions In Urban Green Spaces

Urban areas are main contributors to anthropogenic Greenhouse Gas emissions.While increasing attentions being paid to energy sectors, urban natural emissions, animportant part of the urban GHG blance, haven’t been throughly studied. This thesisbuilt a framework of Urban Green Space Emission Inventory, which tried to link upthe empirical studies and urban green system plannings, set evaluation index andplanning principles for urban green space from a low-emission perspective as well.4typical vegetation types were taken as the research objects, this paper i)established experience model for urban forest and median Emission Factors datasetfor21subclasses of grassland, wetland and farmland, which all based on statisticalanalysis using observed data; ii) set up a category suit for the emission estimation ofurban green spaces, in consideration of both currently used land cover categories inChina and convenience of field observations; iii) established Urban Green EmissionInventory which is accessible to urban planners and verified the inventory withobserved data from literature of urban green space; convert all vegetation types intoTurfgrass Equivalent according to the Emission Factor dataset and use it as evaluationindicator of urban green system; iv) use Urban Green Emission Inventory in2cases,local and sub-basin scale, for the estimation and evaluation of urban green system.The largest potential emission source of vegetation is the obliteration of carbon poolscaused by land cover change. The total Green Emission of Haihe river sub-basin was4.87×10⁵tCO₂-e in2002, however, it increased by45.8%in2010due to thereduction of green land cover caused by urban sprawl. The Urban Green EmissionInventory was also used in the estimation of the green system planning included inTianjin’s zoning plan,2008, which shows that the extra yearly carbon storage storedby the newly planned urban forests will be totally offset by the loss of carbon pooldue to the reduction of farmland, proved again that land cover change has the decisiverole in the Urban Green Inventory. Thus with minimal interference and appropriatemanagement, as well as the increase of green space especially the trees, much moresequestration of Greenhouse Gas could be expected in urban area. Furthermore,statistic data of urban green spaces based on digital line graph in small scale areunderestimated in the total area and lack of detailed classification which would result in an underestimation of carbon sequestration as high as71%. Stratified samplingsurvey could revise the estimation in total area but high precision remote sensing hasthe advantage of speed and accuracy in Urban Green Emission Inventory whichwould made it a more widely used method in the future.