Urban construction promotes urban collaborative development, which has an impact on carbon emissions, so studying the relationship between urban construction and carbon emissions can help explore an effective way to reduce emissions. This article, based on land utilization, energy consumption and other data from 2010 to 2018, Zhejiang province, calculates carbon emissions. We use spatial autocorrelation methods and space metering regression models to explore the spatio-temporal evolution characteristics of carbon emissions in four metropolitan areas and their influencing factors. The results showed that: (1) Hangzhou metropolitan area is the largest carbon emission urban area in Zhejiang, followed by Ningbo, Wenzhou and Jinhua-Yiwu. (2) In terms of spatial distribution, carbon emissions have significant agglomeration characteristics. Obvious spatial heterogeneity can be observed in metropolitan areas. The spatial aggregation of carbon emissions in different metropolitan areas have significant differences. (3) Urban construction helps the synergy and utilization of various cities and towns, promotes efficient configuration and utilization of resources, and then reduces carbon emissions. (4) The influencing factors and driving mechanisms for metropolitan carbon emissions are affected by urban development phases and characteristics, thus forming different spatial features. (5) Metropolitan low-carbon construction tasks and programs are determined by their unique carbon emissions driving mechanisms and spatial aggregation characteristics.

Under the strategic background of high-quality integration of Yangtze River Delta and ecological priority and green development of Yangtze River Economic Belt, it is of great significance to explore the high-quality green development of Yangtze River Delta Urban Agglomeration. This paper constructs a high-quality green development evaluation system from four dimensions of green core power, green innovation industry, green environment base and green development performance. Based on the methods of critical weighting, kernel density estimation, center of gravity standard deviation ellipse and other methods, the equilibrium state, equilibrium degree and equilibrium entropy of high-quality green development of 27 cities in Yangtze River Delta Urban Agglomeration are discussed. The results show that: (1) Generally, the high-quality green development level of the urban agglomeration presents a northwest-southeast pattern and the gravity is located in the east of the center of the region. There are obvious spatial differences in the high-quality green development, but there is no spatial polarization. (2) From the regional perspective, the overall level of high-quality green development is relatively balanced, but with relatively low innovative dimension. From the perspective of city, there is obvious provincial differentiation in the degree of equilibrium, and Shanghai and the cities in Jiangsu and Zhejiang are obviously better than Anhui province. Equilibrium entropy shows that most cities have advantages in coordination degree of high-quality green development and have certain development potential. (3) Innovation level, environmental quality, land intensification and modern industry are common obstacles to high-quality green development. Based on this, the main obstacle types of cities are summarized and their specific obstacles are defined too. Adhering to innovation driven development, building a modern industrial system, strengthening the governance of land space, promoting the intensive, efficient and sustainable use of land, and maintaining a reasonable degree of balance and coordination are the urgent tasks to further promote the high-quality green development in the Yangtze River Delta Urban Agglomeration in the future.

The rapid urbanization process in the Yangtze River Delta has affected the balance between the supply and demand of ecosystem services. In order to realize the integrated and high-quality development of the Yangtze River Delta, it is necessary to explore the impact of urbanization on supply and demand of ecosystem services. Therefore, based on ecological model, Pearson correlation, random forest, local spatial autocorrelation and other methods, this paper analyzes the impact relationship, sensitivity and spatial interaction between urbanization and supply and demand of ecosystem services, and finally proposes ecological management measures. The study found that the comprehensive level of urbanization in the Yangtze River Delta increased by 133.33% from 2000 to 2018; ESDR is positive but shows a decreasing trend, with an average decline rate of 22.39%; urbanization has a significant negative impact on ESDR, with an average increase of 82.34% from 2000 to 2018; food production is more sensitive to population urbanization, carbon storage and habitat quality are more sensitive to economic urbanization, and water conservation and PM_2.5 removal are more sensitive to spatial urbanization. There is a large spatial mismatch between urbanization and ESDR. Therefore, it is suggested to divide the Yangtze River Delta into ecological utilization area, ecological reconstruction area, ecological source area and ecological restoration area, and proposes ecological optimization management measures according to the characteristics of urbanization and supply and demand of ecosystem service.

The relationship between environmental regulation and green development and its impact mechanism are complex and controversial. Based on the panel data of 41 cities in the Yangtze River Delta from 2003 to 2018, this paper first constructs a measurement index system to calculate the green development level and spatial dynamic evolution of each city. Secondly, using the stochastic impacts by regression on population, affluence, and technology (STIRPAT), this paper constructs a panel measurement model to explore the impact of environmental regulation on urban green development. The results show that: (1) The level of environmental regulation and green development in the study area shows an upward trend, but there are significant regional differences. The level of green development has been in a stable pattern of decreasing from southeast to northwest, and the focus of environmental regulation intensity has experienced a spatial evolution from southeast to northwest. (2) On the whole, environmental regulation can affect urban green development significantly, and there is an inverted U-shaped relationship between them, that is, excessive environmental regulation will inhibit the level of urban green development. (3) There is a close linkage between environmental regulation and technological innovation. Environmental regulation mainly affects urban green development through the intermediary path of technological innovation, in which the intermediary effect accounts for about 50.1% of the total effect. The research results can provide some enlightenment for promoting the integrated and high-quality development of the Yangtze River Delta. Local condition-based environmental regulation is the premise to improve the efficiency of urban green development, and pay attention to the promotion of the transformation of urban green development by improving the level of technological innovation.

The rapid urbanization intensified resources consumption. As the essential resources, the water-energy-food is the key for cities to achieve sustainable development. Taking the Yangtze River Delta Urban Agglomeration (YRD) as an example, this study constructed the WEF system stress index (WEF_SI), revealed the evolution characteristics of WEF stress in the study area during 1990-2018, and explored the influencing mechanism of urbanization on the WEF stress. The results showed that: The WEF stress in the YRD increased significantly due to the accelerated integration process after 2010. Although its overall downward trend was obvious, the stress of energy was still the dominant stress on the WEF system. Water stress was stable overall, while food stress surged after 2010. Due to the difference of the resources endowment, economic development level and urbanization process, there were obvious differences in evolution characteristics of WEF stress within the YRD. Urban spatial expansion, urbanization rate, economic development level and residents' consumption significantly affected the WEF stress. Therefore, WEF system management should be based on the evolution characteristics of different resources. Moreover, we should strengthen the supervision of resources consumption and the synergy management among different sectors and regions to promote the sustainable development of the YRD.

Realizing ecosystem service value is the prerequisite of the integrated implementation of regional ecosystem pattern. With the rapid development of China's economy, there are fewer ecological products that can meet people's increasing demand of better life. Guided by the conviction that lucid waters and lush mountains are invaluable assets, we advocate the priority of ecological protection and the new requirements for the realization of the value of ecological products; however, the problems such as inaccurate definition of ecological products and obstacles of trading mechanism are still prominent. The paper took Tianmu Lake Basin as an example and proposed a two-way interaction between the marketization of ecological protection and the improvement of ecological products value. Some conclusions can be drawn as follows: (1) The ecological products of water quality purification service were dominant in the study basin, which equaled the surplus part of the water quality purification service capacity subtracting the safety baseline part for the ecological health benchmark. (2) Based on the distributed hydrological model and water quality model of pollutant transport process, the supply and bottom price of ecological products were accurately calculated. The supply of water quality purification service products was estimated to be 1.37 tons, and bottom price was 11.87 million yuan/t/a, and the zonal price was between 11.87-71.05 million yuan/t/a. (3) According to the relationship between supply and demand of ecological products during the past 10 years, we identified five types of ecological trading mechanism, namely, the transboundary basin compensation (type A1), the ecological restoration (type A2), the agricultural abandonment for non-point source pollution (type B1), the agricultural management for non-point source pollution (type B2), and the ecological benefit payment (type C1). Then we designed a typical trading model between the freshwater shrimp cultivating abandonment and the leisure industry urgement: proposing the definition method of ecological products under the watershed ecological protection health benchmark and the trading unit transforming from non-point source pollution into point source, and realizing the multi-agent trading mechanism. This study was an innovative practice to use the international Payment Ecosystem Servives mechanism in China, which has generated multiple targets, including regional ecological value enhancement, economic benefit and the action of load-reducing for government environmental protection. It also provides a reference for the realization of the ecological product values in areas with developed economy and excellent ecological environment.