Ecological environment quality and resilience assessment is an important prerequisite for ensuring the coordination and stability of socio-economic development and eco-environment protection. Remote sensing technology has provided new approaches for quantitatively evaluating regional ecological environment quality and resilience rapidly, accurately, and objectively. Taking the middle and lower reaches of the Yangtze River Economic Belt (YREBML) as an example, to assess ecological environment quality, this study calculated the remote sensing ecological index (RSEI) based on the Google Earth Engine using Moderate Resolution Imaging Spectroradiometer (MODIS) data with a spatial resolution of 500 m during 2000–2020. An evaluation index to assess ecological resilience and its spatial pattern based on the RSEI of 2000–2020 was then constructed. The evaluation index was constructed from two dimensions, including the sensitivity and adaptability of the RSEI. Finally, this study identified key factors that affect ecological residence based on a structural equation model. The results showed that the overall RSEI was at moderate and good levels in the YREBML during 2000–2020, accounting for more than 85% of the total area. Its spatial characteristics showed that the RSEI was higher in the middle reaches than in the lower reaches of the YREB, and higher in the south than in the north. The overall RSEI in the YREBML showed a decreasing trend during 2000–2020, with 54.36% of the region improving and 45.64% declining. Areas with declining RSEI were concentrated in Anhui, while the increasing RSEI was observed in Zhejiang. In addition, the spatial pattern of ecological resilience was characterized by high resilience in the north and east, and low resilience in the south and west. High resilience areas accounted for 40.48% of the YREBML, mainly contributed by Jiangxi and Hunan provinces. The driving factors analysis results indicated that economic development, natural disaster risk, and environmental pollution would further affect ecological resilience of urban systems. This study provides more scientific and effective data support for ecological environment monitoring and governance.

Frequently occurring flood disasters caused by extreme climate and urbanization processes have become the most common natural hazard and pose a great threat to human society. Therefore, urban flood risk assessment is of great significance for disaster mitigation and prevention. In this paper, the analytic hierarchy process (AHP) was applied to quantify the spatiotemporal variations in flood risk in Wuhan during 2000–2018. A comprehensive flood risk assessment index system was constructed from the hazard, sensitivity, and vulnerability components with seven indices. The results showed that the central urban area, especially the area in the west bank of the Yangtze river, had high risk due to its high flood sensitivity that was determined by land use type and high vulnerability with dense population and per unit GDP. Specifically, the Jianghan, Qiaokou, Jiangan, and Wuchang districts had the highest flood risk, more than 60% of whose area was in medium or above-medium risk regions. During 2000–2018, the flood risk overall showed an increasing trend, with Hongshan district increasing the most, and the year of 2010 was identified as a turning point for rapid risk increase. In addition, the comparison between the risk maps and actual historical inundation point records showed good agreement, indicating that the assessment framework and method proposed in this study can be useful to assist flood mitigation and management, and relevant policy recommendations were proposed based on the assessment results.

The Yangtze River Economic Belt (YREB) is an important part of China’s “two screens and three belts” strategic ecological security barrier, and the urban agglomeration along the YREB is the core of its economic development. However, it has suffered the most from frequent and severe flood disasters that were affected by torrential rains, urbanization, and human activities, with climate change intensifying the potential occurrence of flood disasters in this area. Based on the CMIP6 climate data, this study constructed a flood risk assessment index system and assessed the temporal and spatial changes of the flood risk in the YREB during 2020–2050 under four shared socioeconomic pathways (SSP) scenarios, including SSP126, SSP245, SSP370, and SSP585. From the perspective of temporal change, the results showed that at the grid level, the area of middle-low risk (0.55 < R ≤ 0.65) accounted for 60% of the total area of the YREB and area of high-risk (R > 0.85) fluctuated first and then decreased under the four scenarios, with the area of high-risk being largest in the future under the SSP585 scenario. Specifically, at the city level, around half of the cities in the YREB had faced high flood risk and the risk showed an increasing trend during 2020–2050 under the SSP370 scenario. From the perspective of spatial change, the flood risk of the YREB presented a spatial pattern of low in the west and high in the east, with high risk mainly concentrated in the cities in the lower reaches of the YREB and also Chongqing and Sichuan. Compared with SSP126 and SSP245 scenarios, it showed that high-risk areas were larger under high emission scenarios SSP370 and SSP585, which were mostly concentrated in middle and lower reaches of the YREB and the cities of Chongqing and Chengdu during 2020–2050. Especially, flood risk showed an increasing trend in the middle and lower reaches of the YREB during 2020–2050, and the regions with high vulnerability would have greater socio-economic losses. The finding would provide scientific support for resilience improvement, risk reduction and management, and formulating policies to achieve green and sustainable development in the YREB.

With rapid development of the economy and urbanization, water-related environmental risk in urban areas has increased and hindered social-economic development and ecological protection. The assessment of water-related environmental risk is of vital importance to the sustainable development of the Yangtze River Economic Belt (YREB). This study constructed a comprehensive assessment index system for water-related environmental risks from three perspectives: the hazards posed by risk sources, the effectiveness of the control mechanisms, and the vulnerability of the risk receptors. Employing the entropy method, the water-related environmental risks of cities in the YREB from 2000 to 2015 were comprehensively evaluated, and the obstacle degree model was used to analyze the associated influencing factors of the water-related environmental risk. The results showed that the overall level of water-related environmental risk of the YREB presented a significant spatial gradient characterized by “downstream risk > midstream risk > upstream risk”. The areas with higher risks were mainly distributed in the Yangtze River Delta in the downstream area, and Wuhan and Changsha in the midstream area, where their risk receptors were highly vulnerable, and efforts should be made to improve the resilience of these areas. In terms of temporal change, the average value of the comprehensive water-related environmental risk of the YREB dropped from 0.493 in 2005 to 0.392 in 2015, with a reduction rate ranging from about 16.55 to 25.76%. The number of cities with medium-high to high risk had gradually decreased, and the number of cities with medium, medium-low, and low risk continued to increase. The water-related environmental risk of the YREB as a whole is in the transition stage from high risk level to medium and low risk level. Specifically, the hazards posed by risk sources had increased continually, and especially increased significantly in the midstream of the YREB; the effectiveness of risk control mechanisms had increased throughout the region, with downstream cities mainly having a high level of effectiveness; the areas with high vulnerability of the risk receptors were mainly concentrated in the Yangtze River Delta and showed an upward trend. Overall, the main source of water-related environmental risks and differences among the upstream, midstream and downstream cities had shifted from the hazards posed by risk sources to the effectiveness of risk control mechanisms and the vulnerability of the risk receptor. The main factors affecting the water-related environmental risk in the order of average obstacle degree were per capita GDP (34.43%), the number of beds per thousand people (18.70%) and the industrial structure height (15.55%). Therefore, promoting the adjustment of industrial structure, improving economic efficiency, developing the regional social economy, and improving and perfecting the construction of environmental protection infrastructure are effective ways to realize the mitigation and resolution of water-related environmental risks.