Theories And Methedologies Of Climate Change Vulnerability Comprehensive Assessment And Their Application In Urban Area

Since the 1980s, global climate change, characterized by global warming, has a great deal of attention from governments, international societies and scientific researchers. Beginning in the 1990s, when the idea of fragility was introduced into the research domain of climate change, and more significantly, in2001 when the third assessment report gave a clear definition of climate change vulnerability, climate change vulnerability has become a focus and a hot-spot domain of research on global climate change. Since the turn of 21st century, foreign scholars from different fields and disciplines have discussed the conceptual framework of vulnerability to climate change and launched practical climate change vulnerability assessments on agriculture, forestry, water resources, ecological systems, human health and the socio-economic system. Compared with research abroad, vulnerability to climate change research in China has started later. This research mainly focused on the overview of the concept of vulnerability to climate change abroad, and also some case studies on agriculture and forestry ecosystem based on climate change impact analysis, which rarely involved the study of theory and methodology of climate change vulnerability and had a limited focus on natural systems. On the other hand, in recent years, governments of different countries and the relevant institutions like IPCC, UNFCCC, and UNEP have considered the issues of climate change on city scale as a focal point in the global climate change research field, and have also actively promoted "Climate Change Action Plan" and "Low Carbon City" planning and construction. Thus, the study of climate change vulnerability at the urban scale is so meaningful, not only for improving and expanding the theories and methodologies of climate change vulnerability at the urban scale, but also for guiding the urban relative planning and strategies in response to climate change with scientific knowledge.Shanghai is a typical estuarine city. On the one hand, this city is a vulnerable estuarine ecosystem, which is simply affected by sea level rise, extreme climate events, salt water intrusion, degradation of wetland habitats, water resource change and so on. On the other hand, Shanghai is also an international metropolitan area with a high population density, economic resource density, and the highest urbanization rate in China, where climate change has a dramatic impact on social life and economy. Thus, the case study of Shanghai has a strategic significance to urban sustainable development with the background of global climate change and fast urbanization processes, which could be also referenced by other coastal cities and estuarine cities. This paper addressed the relative theories and methodologies of climate change vulnerability in an urbanized area, including the coupling relationship between urbanization and climate change, the conceptual framework of climate change vulnerability of an urbanized area, the conceptual model of vulnerability assessment, and also related assessment methodologies and techniques. Based on the theoretical framework, the estuarine city of Shanghai, as a case study, was studied through the aspect of climate change vulnerability integrated assessment. The main conclusions in this paper are comprised of both theoretical and practical aspects. Some strategic recommendations of mitigation and adaptation polices were also proposed for Shanghai in response to climate change.1) Study of relative theories and methodologies of climate change vulnerability in an urbanized areaThere is an objective dynamic coupling relationship between urbanization and local climate change, which consists of the multi-level network effects of climate change on urban "social-economic-nature" complex ecosystems, the pressure of social-economic development, energy requirement and urban land sprawl in the process of urbanization on local climate change, and the dynamic coupling relationship of environmental Kuznets curve between urbanization and climate change.The conceptual model of climate change vulnerability assessment in an urbanized area was established in this research. According to the model, the structural elements of climate change vulnerability are exposure, sensitivity and adaptive capacity. The exposure elements are climate change exposure and urbanization exposure. The elements of strategy output in response to climate change are mitigation and adaptation. Each element in the model has its unique characteristics of temporal and spatial scales, and system attribution. Different kinds of flow type could be identified among elements, including decision flow, affecting flow, response flow and information flow.According to the model, the whole process of urban climate change vulnerability assessment could be divided into six analysis modules, including climate change fact and prediction, urbanization stress on local climate change, climate change impacts on urban complex ecosystems and index system based climate change vulnerability assessment at the spatial-temporal scale. Relative methodologies and techniques for assessment include climate change scenario analysis, model stimulation, evaluation index system, GIS and RS techniques, and decision-maker support tools.2) The case study of Shanghai climate change vulnerability assessmentIn terms of the urbanization impact on local climate change, in the most recent 50 years, there was a significant warming trend in the urban area with the rate of 0.51℃/10a; distinguishing features of temperature change were identified in different stages of the urbanization process. Since the 1990s, when Shanghai phased into the high-speed urbanization process, the degree of increase in temperature was higher, while the rate of urbanization contribution on local warming was 49.51%. Based on the study of climate change facts in Shanghai, the drive of social-economic development, energy requirement increases, and urban land sprawl were highlighted with the consideration of their stresses on local climate change. The results indicate that the stresses of indexes of gross domestic product, non-agricultural population, consumption of industrial energy, area of floor space of completed buildings and agricultural area, and differences of annual mean temperatures between urban and suburban areas are extremely significant. The dynamic relationship between the index of non-agricultural population and local climate change is perfectly reflected by a logarithmic growth curve, while a cubic polynomial curve is suitable to other indexes. Combining these signal indexes, UPI (Urban Pressure Index) was established to describe the whole urbanization process stress on local climate change. The results indicate that different aspects of UPI stress on local climate change in different stages of the urbanization process. The urbanization process could be identified as three different stages as follows:low intensity stress phrase, linear stress phrase, and slow stress phrase. The variation of three phrases also verified the theoretical hypothesis of an environmental Kuznets curve relating urbanization and climate change.The impacts of climate change affecting the "social-economy-nature" ecosystem in Shanghai were studied qualitatively and quantitatively. Qualitative analysis shows that the impacts of climate change on the natural eco-system in Shanghai were salt water intrusion, increases of storm surges and flood disasters, coastal erosion and decrease of tidal wetlands, decreasing stability of urban water supply systems, water demand increases, and water pollution. The impacts on the social and economic system include impacts on agriculture, transportation, finance, insurance and tourism industries; increasing demand for energy; impacts on coastal protection works, flood drainage systems, water supply, and other infrastructure; decreasing air quality and its impacts on human health. In order to make a further discussion on quantitative assessments of climate change impacts, this paper uses the AVIM2 "atmosphere-vegetation" ecological process model to quantitative evaluate the impacts on the net primary productivity of Shanghai's farmland ecosystem by climate change and agricultural land use change.The assessment of comprehensive climate change vulnerability, based on the evaluation indicator system, analyzes the change of the Urban Climate Change Vulnerability Index (UCCVI) on the scales of time and space, respectively. From the perspective of time series, during the period from 1998 to 2006, Shanghai UCCVI shows a small fluctuation and a decreasing trend in total amount, which is due to fossil fuel consumption, hydrology and water resources, vegetation ecosystem function, human health, economic development demand on energy, and human and social capital. From the view of spatial variation, the most vulnerable area to climate change in Shanghai comprise 447.66 km2of area, accounting for 7.06% of the total area of Shanghai, and highly vulnerable land area is 1849.07 km2, accounting for 29.16%.3) Shanghai's strategy on climate changeBased on the comprehensive assessment of the climate change vulnerability of Shanghai, we put forward coping strategies corresponding to mitigation and adaptation. The mitigation strategies include the optimization of industrial structure and transforming economic growth models; development of renewable energy, improvement of the energy consumption structure; energy efficiency improvement; promoting the "low-carbon city" as the entry point and promotion of "carbon trading" development through market-oriented measures. Adaptation strategies include building an ecological security pattern for Shanghai; construction of urban forests, increasing urban carbon sinks; regulation of urban water resources balance, increasing the response capacity to flood disaster; identification and response to climate change impacts on urban human health; establishment of an effective contingency; and response mechanisms to climate disaster.