Longyu Shi

China's Cities Need to Grow in a More Compact Way

ince the 1990s, China has undergone astonishing economicgrowth,anditsextensiveurbanizationhasbecomeoneofthemost striking development signatures anywhere in the world.With the world’s largest urban population, China’s urbanizationexperience provides meaningful insights on future urban devel-opmentinothercountries.

Effects of spatial form on urban commute for major cities in China

The global phenomenon of urbanization increases the importance of compact-city development. China’s rapid urban development has resulted in unprecedented urban population growth and built-up area expansion, but its effects on urban morphology and mobility are only partly understood. City compactness can be measured simply using urban spatial form or morphology: the more concentrated the built-up area, the more compact the city is. Here we show that 35 major cities in China are not compact in spatial form and that their compactness is not improving over time. Our results reveal close correlations between changes in urbanization rate and changes in city compactness as well as between city compactness and commuting time (CT), indicating that the high rate of urbanization without adequate planning has contributed to the poor compactness of Chinese cities, which has further increased CT. We suggest that continuing urban sprawl with low land use efficiency and low urban form compactness will make cities in China more congested and threaten China’s sustainable urbanization.

Evaluation of Shangri-La County’s tourism resources and ecotourism carrying capacity

Ecotourism is an important path to sustainable tourism that has experienced rapid development in recent years. Thus, ecological principles have been considered as the guidelines for tourism and the need to protect the eco-environment has increased substantially. On this basis, the ecotourism planning, a new paradigm for tourism planning, has emerged and it has benefits in terms of both economic development and environmental conservation. The ecotourism planning is based on two important criteria: local tourism resources and ecotourism carrying capacity. In this study, we aimed to investigate the local tourism resources and calculate the ecotourism carrying capacity of Shangri-La County as an example. The results showed that Shangri-La County has abundant tourism resources and a vast diversity of tourism products. However, the natural resources in Shangri-La County are currently being exploited beyond the carrying capacity. Solutions to this problem mainly include sustainable exploitation of tourism resources; better handling of tourism demands by improving the repartitioning of tourism flow; and the development of a digital system to facilitate the management of tourism.

Trends of maximum temperature, minimum temperature and diurnal temperature range and their correlations with urbanisation in Xiamen, China

This study examines variations of maximum temperature, minimum temperature and diurnal temperature range (DTR) and their possible correlations to urbanisation in Xiamen, a coastal city in SE China. The underlying meteorological data used are the daily temperature time series from Xiamen Meteorological Station from 1954 to 2007. We selected four urbanisation indices, urban population, gross domestic product, built-up area and gross electricity consumption, to investigate correlations with temperature variables over the period 1981–2007. The results show that annual maximum temperature, minimum temperature and DTR increased from 1954 to 2007 at a rate of 0.33°C/10 years, 0.18°C/10 years and 0.15°C/10 years, respectively. Similarly, the seasonal maximum temperature, minimum temperature and DTR rose over the same period, with stronger increasing trends in winter and summer than in spring and autumn. The four selected urbanisation indices were all positively correlated with the three temperature variables, although more significantly with maximum and minimum temperatures than with DTR. The influence of urbanisation appears to be slightly stronger on maximum temperature than on minimum temperature in this area.

A method to estimate urban optimum population conditions: a case study of Xiamen, China

Maintaining an optimum population is crucial for urban sustainable development. A happiness degree model was constructed to estimate the optimum population of Xiamen, southern China. Happiness degree was defined as the total satisfaction of households working and living in Xiamen in terms of possessing and/or consuming certain resources. The optimum city size was considered for a city in which the population has maximised the happiness degree. The resources considered in the assessment were those possessed or consumed by citizens: GDP, investment in education and in science and technology, water, electricity, housing, green land, transportation. The results show that the optimum population of Xiamen in 2007 would be about 1.66 million, i.e. the actual population of nearly 2.43 million is obviously too large. Insufficient electricity supply was the most significant constraint for Xiamen as a sustainable city.

Public perception of smog: A case study in Ningbo City, China

ABSTRACT Smog has become a public environmental crisis in most areas of China, and in response, research efforts have mainly focused on the chemical properties of smog and its impact on human health. However, in-depth research on the public’s perception of smog has not yet been conducted. A survey of residents living around eight state-controlled atmospheric environmental monitoring sites in Ningbo City was conducted using stratified sampling. The data was statistically analyzed to investigate people’s views and behavioral tendencies in smog weather, the influence of different media reports on public outlook, and public opinions on the local atmosphere and pollution management in different areas. The results showed that people’s perception of smog differs greatly from actual conditions, indicating that the public opinion tends to deviate when faced with a public crisis. Mainstream media (TV, newspaper, etc.), accounting for 67% of all media sources, are the main source for dissemination of smog information. The main sources of pollution, in order of decreasing contribution, according to residents of Ningbo City are as follows: motor vehicle exhaust, industrial coal combustion, large-scale construction, biomass burning, and kitchen fumes. Implications: Since 2011, most areas of China have been affected by frequent smog. Most research on smog has been concentrated on its causes, alert systems, and prevention measures, whereas in-depth research on the public perception of smog has not yet been conducted. When a risky environmental event such as smog occurs, consequences may be more serious than the event itself will cause if people take irrational measures because of lacking relevant knowledge. Therefore, investigating people’s attitude and response to smog is both theoretically and practically significant.

Effects of a Compact City on Urban Resources and Environment

AbstractSince the proposition of compact city theory, the sustainability of the compact city and whether it represents an appropriate orientation for urban development have been heatedly discussed. How urban compactness will affect resource utilization and environmental pollution is still unknown. By fully considering the core connotations of the compact city, a comprehensive evaluation indicator system was established to measure the compactness of 35 major cities in China in 2000 and 2010. The results showed the prevalence of urban sprawl. Multiple linear regression was employed to investigate the relationship between urban compactness and resource consumption and pollutant discharges in China. The results indicated that compact urban development can promote a more efficient utilization of urban resources with no obvious impact on the urban environment, especially in the reduction of pollutant emissions.

Estimates of exposure of a coastal city to spatial use changes – a case study in Xiamen

The coastal zone is an area where the interaction between land and sea is intense. It constitutes a highly dynamic and complex system that plays an important role in human survival and development. The vulnerability of coastal cities has increased due to global changes such as hazards, sea level rise, spatial use changes, etc. This study took Xiamen, a coastal city in Fujian Province, as an example to estimate exposure in relation to spatial use changes. The exposure value was defined as the land use intensity (LUI), comprised of five land-use/land-cover (LULC) types, and the shoreline use intensity (SUI), comprising 10 shoreline use types. The dynamic changes of these variables are discussed in detail from 1987 to 2007. The result show that the exposure value rose swiftly from 2.530 in 1987 to 2.707 in 1992, increased slightly to 2.747 in 1997 and 2.761 in 2002, and finally decreased slowly to 2.743 in 2007. The main reasons for such changes and future research directions are discussed.

Air pollution-oriented ecological risk assessment in Xiamen city, China

ABSTRACT Urban energy consumption is one of the most important causes of air pollution. Air pollution-oriented ecological risk assessment is of great significance to the promotion of urban environmental protection. This paper focuses on ecological risk in Xiamen city caused by air pollutant discharge from urban energy consumption. The Long-range Energy Alternatives Planning model was used to establish two scenarios of energy consumption in Xiamen city, and based on different scenarios, we estimated urban energy consumption and discharge quantity of air pollutant (DQAP). A box model and an expert scoring method were used to calculate the air pollution burden (APB) of SO2, NO2, CO, PM10 and PM2.5 and to obtain the probabilities of different air pollution loads. An ecological risk assessment model was developed and utilized to predict Xiamen city’s ecological risks in 2020. The results showed that under an energy-saving scenario, the ecological risks for PM2.5, SO2 and NO2 are high, whereas the ecological risks for CO and PM10 are low. Under a baseline scenario, the ecological risks for PM2.5, SO2 and NO2 are moderate, whereas the ecological risks for CO and PM10 are low. In addition, the APB of SO2, NO2, CO, and PM2.5, but not of PM10, is predicted to rise. In the simulation, energy generation from coal is the main source of air pollution. Although the DQAP from automobiles is not high, it is predicted to rise year-on-year. In summary, the ecological risk due to pollution in Xiamen city is high, and the main pollutants are SO2, NO2 and PM2.5.

Factor decomposition of carbon emissions in Chinese megacities

In this article, per capita urban carbon emissions were decomposed into manufacturing, transportation, and construction sectors using logarithmic mean Divisia index (LMDI) method. This new decomposition method can provide information about specific drivers of carbon emissions, including urban growth and resident living standards, rather than general demographic and economic factors identified by traditional methods. Using four Chinese megacities (Beijing, Tianjin, Shanghai, and Chongqing) as case studies, we analyzed the factors that influenced per capita carbon emissions from 2010 to 2015. The results showed that per capita carbon emissions increased in Tianjin and Chongqing whereas decreased in Beijing and Shanghai, and that manufacturing was a key driving force. In these four megacities, energy conservation strategies were successfully implemented despite poor energy structure optimization during 2010-2015. Development of manufacturing and improvement of resident living standards in the cities led to an increase in carbon emissions. The unique dual-core urban form of Tianjin might mitigate the increased carbon emissions caused by the transportation sector. Reductions in carbon emissions could be achieved by further optimizing energy structures, limiting the number of private cars, and controlling per capita construction.