Climate Change Risk Assessement:Modeling And Applications

Climate change is one of the most important environmental issues as well as a global challenge.It affects socioeconomic system via natural environment.In the future climate,there may be more extreme events and disasters which cause more adverse concequences.China is one of the most vulnerable nations,and thus coping with climate change is crucial for national plans.From a policy perspective,understanding climate change risk is helpful for reducing impacts.This paper focuses on climate change risk assessment with respect to both impacts and mitigation.Some innovative results are obtained as follows.(1)An integrated index containing exposure,sensitivity and adaptive capacity is developed to measure regional vulnerability to drought.Accordingly,65 cities in Anhui,Henan,Jiangsu and Shandong provinces of China are chosen as the study area.The results show that Anhui and Henan are more vulnerable to drought,and the proportions of cities with inefficient resilience to drought in the two provinces are over 50%.Compared with coastal areas,the inland regions have more drought-vulnerable cities.In addition,the cities in the south are less vulnerable to drought than those in the central and north regions.It also indicates that economic development is a crucial way for drought vulnerability reduction.(2)An integrated index of drought risk is developed following the pressure-state-impact process in which drought hazard and vulnerability are reflected by two stages of pressure-state and state-impact respectively.Then,this study evaluates 31 provinces,municipalities and autonomous regions of China,and the tempo-spatial patterns of regional drought hazard,vulnerability and risk during 2006-2011 are presented.Moreover,the determinants of risk in different parts of China are also investigated.The results suggest that the northeast and southwest of China are more potential to be affected by drought due to the high degree of hazard and vulnerability.The dominant factor affecting drought risk in the northwest is vulnerability,because the hazard in this part is comparatively low.However,although the drought situation is severe in the middle and lower reaches of the Yangtze River and the southeastern coastal areas,the strong resilience to drought makes the risk remain low.(3)An investigation on China's socioeconomic risk from extreme events under climate change is made with a focus on a projection over the next few decades.We construct empirical relationships between damages from weather-related disasters and their determinants using a hierarchical Bayesian approach.These are used to estimate future socioeconomic damages as well as associated uncertainty bounds given specified climate and development scenarios.The results suggest that in a Bayesian framework jointly modeling the dependence between two kinds of damages with the data being spatially pooled effectively reduces the uncertainties in the model parameters and predictions.Based on the model estimates considering exposure only,southwest and central regions and Hainan Island of China are likely to have larger percentage of population at risk,while Sichuan and Hunan would have larger economic losses.In the climate conditions projected for the future the national damages are expected to be higher.(4)In recent years some ambitious carbon reduction targets have been proposed by the Chinese government,and this study investigates how challenging they are.A hierarchical Bayesian approach is employed to construct the relationships between energy consumption and influencing factors accounting for model uncertainty,regional heterogeneity,and cross-sectional dependence.Given specified development scenarios,the combined probabilistic forecasts of energy demand and carbon dioxide emissions at the provincial and national levels are made by Bayesian model averaging.The results show that the national total energy use would increase to 6.18-6.94 and 7.01-7.87 billion tce by 2040 in two scenarios.The low emissions scenario suggests that the emissions peak would appear in 2025,reaching 11.6 billion metric tons.However,considering the full range of the estimated carbon dioxide emissions in the scenarios,it seems challenging to ensure the peak before 2030.By comparison,the reduction targets of carbon intensity by 2020 and 2030 could be achieved in general.The models developed in this paper could help understand climate change risk across the regions of China,and provide theoretical basis and decision support for building high adaptive capacity,making scietific mitigation plans,and reducing socio-economic damages.