| The Fifth Report of the Intergovernmental Panel on Climate Change (IPCC) shows that the global warming has been an undoubted fact in recent 100 years. The global warming has accelerated melting of glaciers and rising of sea water temperature, which finally result in global sea-level rise (SLR). The prospect of climate change, in particular SLR caused by climate change and its impacts on low lying coastal areas, have generated worldwide attention among scientists, governments and managers of coastal regions. The coastal areas, as vital hubs in terms of settlement, national economy and social development, are particularly sensitive to SLR. SLR, at the estimated rate, will pose a significant threat to coastal areas, as a higher sea-level provides a higher base for storm surges to build upon. Thus, storm events occurring in conditions of higher mean-sea levels will enable inundation and damaging waves to penetrate further inland, increasing flood events and the subsequent impacts on the socio-economic development of the coastal region.In China, the coastal zones are densely populated and highly developed economically. With 42% of the total population and 13% of the territory of China, The coastal economic regions generates more than 60% of the national gross domestic product (GDP). The coastal regions vital role in the strategic layout of national socio-economic development. Under the high pressures of global climate change and human activities, vulnerability of the coastal regions is increasingly prominent. The SLR, storm surges, salt water intrusion, coastal erosion and degradation of ecosystem service, etc. threaten significantly the coastal defenses, eco-security and sosio-economin development in the Chinese coastal zones. The global climate change is becoming one of the great challenges which the coastal regions are facing for the sustainable socio-economic development.Located on the eastern coast and the Yangtze Delta in China, the megacity of Shanghai is a notable example which is particularly sensitive to SLR and associated storm surge risks. The Shanghai metropolitan region has a land area of 6,340 km2 and is surrounded on three sides by the East China Sea, the Yangtze Estuary and Hangzhou Bay. The region is an important industrial, scientific, technological, cultural and economic center, and China’s largest harbour city. The city is also the fastest growing region among all major Chinese cities with the population increasing from 5.2 million in 1949 to more than 20 million in 2010. With 1.2 % of the total population of China, Shanghai generates 4.9 % of the nation’s industrial output and 4.2 % of the GDP. However, the elevation of the region generally lies between 3-4 m and flooding caused by SLR and associated storm surges has been the most damaging disaster in the city.Research into the vulnerability assessment of SLR and associated storm surges on the socio-economic development and the formulation of feasible mitigation and adaptation strategies are important prerequisites for securing sustainable development in coastal regions. In this context, the socio-economic vulnerability of a Chinese coastal city to SLR and associated storm surges was carried out, taking the Shanghai metropolitan region as a case study. The possible impact of the flooding risks caused by SLR coupled with storm surges on the socio-economic development in the region was analyzed by the Source-Pathway-Receptor-Consequence (SPRC) model. An process-based index system for vulnerability assessment was developed. A quantitative spatial assessment method based on the GIS platform was established by quantifying each indicator and calculating and grading the vulnerability index. The vulnerability assessment was performed under the scenario of the SLR coupled with storm surge and assuming the present infrastructure for three periods:2030,2050, and 2100. Based on the results of this study, mitigation and adaptation measures should be considered for securing sustainable socio-economic development in the region. The main results from this study are summarized as follows:(1) A conceptual model of "Source-Pathway-Receptor-Consequence, SPRC" has been established for the assessment of socio-economic vulnerability of Shanghai to SLR and associated storm surges. The SPRC model is a linear concept model based on cause-and-effect relationship. With relatively strong logic spatial relationship, it can reflect the interaction the "source" and "receptor" and the influencing process by analyzing the source and receptor to evaluate the influence of risk source on the receptor. In the SPRC model, the SLR coupled with storm surge caused by climate changes is the source (S) of impacting directly the socio-economic system of the coastal region. Pathways (P) are the routes between the source and the receptors, including seawall defense, land subsidence and land elevation (DEM). If storm events occur in conditions of higher sea levels, it may excess the existing seawalls and result in flood events and the subsequent consequences (C) of impacts on the socio-economic development of the region. The land elevation would determine the severity of flooding damages, while land subsidence could increase the rate of SLR and further exacerbate the impacts. Receptors (R) are the coastal systems that would be impacted by the flood events within the case study boundaries. In this study, six categories of receptors have been classified for the the Shanghai metropolitan region, i.e. the land for towns, land for industry, land for agriculture and forestry, water areas, roads and undeveloped land with natural or semi-natural vegetation.(2) A process-based indicator system and a methodology for quantitatively spatio-temporal assessment on the socio-economic vulnerability of Shanghai to SLR and associated storm surges has been developed. By adopting the analysis results of SPRC model and the IPCC definition of vulnerability, an index system for vulnerability assessment could be developed. The indicators were selected from the aspects of exposure, sensitivity and adaptation, assuming that socio-economic vulnerability undergoing flooding risks caused by SLR associated with storm surges is driven by these key conditions. The flooding depth, density of population, GDP per capita, added value per unit land, loss rate under flooding, and fiscal revenue were selected as the key indicators. A quantitative spatial assessment method based on a GIS platform was established by quantifying each indicator, calculating a vulnerability index (VI) and then grading the vulnerability index.(3) A quantitatively spatio-temporal assessment on the socio-economic vulnerability in the metropolitan region of Shanghai to sea level rise and associated storm surge has been realized. The vulnerability assessment was performed under the scenario of the SLR coupled with storm surge and assuming the present infrastructure for three periods:2030,2050, and 2100.The projected vulnerability assessment for 2030 show that the SLR is estimated to be 8.7 cm and an associated storm surge with the intensity of Typhoon 9711 is projected to flood 1.5% of the total metropolitan area of Shanghai. In general,99.3% of the metropolitan area of Shanghai shows no vulnerability (with a VI score of 0), indicating that the impact of SLR and associated storm surges on the socio-economic development is negligible under the present infrastructure of flood defences. The percentages of areas with low, moderate and high vulnerability account for 0.5%, 0.1% and 0.1% of the metropolitan area of Shanghai, respectively, which are mainly located in the coastal areas of Fengxian (FX), Pudong (PD) districts and Changxing Island.In 2050, the SLR is estimated to be 18.6 cm and an associated storm surge intensity of Typhoon 9711 will overtop the seawalls in Jinshan (JS), Fengxian (FX) districts, Changxing and Hengsha Islands, as well as the levees in Songjiang (SJ), Pudong (PD) and Baoshan (BS) districts. About 37.0% of the total metropolitan area of Shanghai will be flooded. The percentage area of the municipality of Shanghai with no vulnerability decreases to 62.8%, while the percentage areas with low, moderate and high vulnerability increase significantly to 5.3 %,8.0 %and 23.9 %of the metropolitan area of Shanghai, respectively, which are mainly located in the Central Urban area (CU), Jinshan (JS), Fengxian (FX), Songjiang (SJ), Pudong (PD) districts and Changxing Island.The SLR is estimated to be 43.3 cm in 2100. An associated storm surge intensity of Typhoon 9711 will overtop nearly half length of the seawalls and levees, and about 50.0 % of the municipality of Shanghai will be flooded. The percentage area of the municipality of Shanghai with no vulnerability decreases further to 50.1 %. While the percentage areas with low, moderate and high vulnerability will amount to 12.9%, 6.3 % and 30.7 % of the metropolitan area of Shanghai, respectively, which occur in almost all the districts, especially in the Central Urban area (CU), except Qingpu (QP) and Jiading (JD) districts.(4) Mitigation and adaptation measures have been put forward to cope with the possible threats of sea-level rise and associated storm surge on the socio-economic development in the metropolitan region of Shanghai. The application of the SPRC model, the methodology and the results from this study could assist with the objective and quantitative assessment of the socio-economic vulnerability of Shanghai undergoing the impacts of SLR and associated storm surges. Based on the results from this study, the following mitigation and adaptation measures have put forward. These should include 1) to control the ground subsidence rate in the region; 2) to strengthen the coastal defense and infrastructure security; 3) to incorporate the impacts of global climate change into the socio-economic development planning; 4) to restructure and optimize the industrial structures; 5) to establish and improve the early warning system to storm surge disaster; 6) to establish and improve the emergency response system to the extreme weather events, and strengthen the emergency drilling to disasters; 7) to enhance the scientific researches on global climate change. |
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