Spatio-Temporal Evolution And Influencing Mechanism Of CO₂ Emissions From Urban Transport In Wuhan City

In recent years,the city’s rapid economic development and urban space expansion lead to the rapid growth of residents travel demand and urban motorization.Urban traffic congestion and haze pollution are getting worse,the energy consumption and carbon emissions increasing significantly.Cities,is becoming the most intensive place of carbon emissions.Therefore,how to realize the sustainable development of urban traffic,and to solve the contradiction between traffic demand and carbon emission reduction,is becoming a pressing issue to be solved.Based on the problem,this study analyses the spatial-temporal evolution and influencing mechanism in Wuhan city,in order to provide theoretical guidance and reference for the reduction of carbon emissions and the construction of low-carbon transportation.Current research on urban transport carbon emissions are mostly concentrated in the calculation of the overall urban transport carbon emissions and its influencing factors,in contrast,the research on the spatial analysis of carbon emissions is relatively scarce.On the basis of spatial vector data,traffic data and social economic data in Wuhan City from 2003 to 2013,this study calculates carbon emissions from comprehensive transport and different traflfic modes by building the urban transport carbon emission models.At the same time,this paper establishes the spatial distribution index system and models of transport carbon emissions based on traffic demand and supply from the view of geographical space,and analyses the spatial-temporal evolution and influencing mechanism of transport carbon emissions in Wuhan city from 2003 to 2013.The analysis will play an important role in the rational development of urban transport and the traffic carbon emissions reduction,and it is also critical to guide the construction of low-carbon transportation.The main conclusions and research findings of the study are as follows:(1)The comprehensive transport carbon emissions in Wuhan city from 2003 to 2013 shows a linear increasing trend and it experiences three periods of wavelike decrease,steady growth and fast rising.The amount of comprehensive transport carbon emissions increased from 1,902,300 tons in 1990 to 5,854,300 tons in 2013,its component structure difference significantly expanded,and the structure tend to be the instable inverted pyramid shape.The carbon emissions proportion structure of public transport,private transport,freight transport and other modes of transport changed from 35.5%:38.0%:17.1%:9.4%in 2003 to 17.1%:68.6%:11.3%:3.0%in 2013.The temporal evolution of public transport carbon emissions shows a spiral trend,and its proportion accounts for the comprehensive transport carbon emissions dropped significantly.The private transport carbon emission becomes the order parameter of comprehensive transport carbon emissions,and its amounts increased from 724,000 tons in 1990 to 4,019,000 tons in 2013.Urban transport carbon emissions efficiency is the result of coupling factors,and the carbon emission efficiency of bus is the highest,the carbon emission efficiency of private car is the lowest.(2)Urban transport carbon emission depends on the compounding effect of traffic demand and traffic supply.Traffic supply is the material base and spatial carrier of transport carbon emissions,while the traffic demand is the driving force of transport carbon emissions,and it’s the product of people to meet their travel demand.(3)The spatial evolution patterns of transport carbon emissions in Wuhan city shows a dynamic trend of polarization structure to core-periphery structure,and it gradually locks down in the process of smooth evolution.The high-value areas of transport carbon emissions in Wuhan city are mainly distributed within the third ring area,and extend along the direction of rail transit line 1,and 2.The area of central Hankou and Wuhan East Lake High-tech Development Zone are the main gathering places for high-value areas of transport carbon emissions.The difference of total transport carbon emissions amount between regions is enlarged at first and then reduced.The regional distribution of per capita transport carbon emission shows a basin-shape pattern,and it is opposite with the distribution pattern of total transport carbon emissions.The per capita transport carbon emission within the third ring area is the lowest,along it around the highest per capita transport carbon emission.The per capita transport carbon emission and per area transport carbon emission increasing stably,and the difference or imbalance between them expand obviously.(4)There is a strong correlation between urban transport carbon emissions and economic and social factors,and this correlation shows a significant allometric relationship.Between urban economic development,urban expansion,infrastructure construction and transport carbon emissions showing negative allometric relationships,while population,motor vehicles and transport carbon emissions are positively allometric relationships.Number of motor vehicles and highway mileage are the decisive factors in the growing process of urban transport carbon emissions,and they are positively correlated.The increment of transport carbon emissions caused by the increase of motor vehicles is much larger than the decrement of transport carbon emissions benefited from the energy-saving technological progress and improvement of fuel efficiency.The growth of the road mileage stimulated vehicle owner to travel by car,and the increase of traffic supply,in turn,produced a new transport carbon emission because of the attraction effect.(5)Based on the analyses of spatial-temporal evolution and influencing mechanism in Wuhan city,this study proposes a complete optimization path for construct low-carbon transport from the perspective of source to process to end.To begin with,in the source stage,optimization measures are proposed from the perspective of land use planning,transportation planning,and urban spatial planning.Next,in the process stage,policy suggestions are made from the optimizing of traffic supply structure and improvement of traffic supply level.Finally,in the end stage,advices are given from the control of excessive growth of car and the promotion of green transport,etc.