The risk of marine disasters based on flooding is one of the most significant natural disasters in coastal zones. It can be said that flooding in coastal zones has typical sea–land characteristics. Yet, relatively little research has been done in this area. Thus, by using the characteristics of marine disaster risk based on flooding in Qingdao and combining marine science and land science methods, this paper constructs a targeted indicator system for the flooding risk from marine disasters from the perspectives of the disaster natural chain and flooding process. According to the results, the Integrated Risk Index of marine disasters based on flooding in Qingdao is 0.3694, which represents a medium risk level for natural disasters in China’s major coastal areas. The first- and third-level indicators with large contribution rates are almost all natural indicators. This indicates that the natural disaster process and disaster chain greatly affect the flooding disaster risk in Qingdao. However, although natural factors play large roles in the risk of disaster, preventive methods implemented by humans can still have a positive effect on disaster reduction. Therefore, human society should still proceed with understanding disasters from natural processes, change their passive response to active adaptation, and actively strengthen preventive measures to alleviate the adverse impacts of increasingly serious natural disasters.

Various strategies have been proposed to enhance the adaptive capacity to climate change. The majority of studies evaluating adaptive capacity have focused on the provincial level, with relatively fewer studies conducted at the municipal or sub-municipal levels. Also, much of the research tends to concentrate on specific aspects of climate change impacts. The Chengdu-Chongqing region faces substantial challenges due to climate change, making the strengthening of urban capacity for climate change adaptation particularly crucial. This study constructs an evaluation index system for urban climate change adaptive capacity of Chengdu and Chongqing from 2017 to 2023. The findings indicate substantial improvements in adaptive capacity, driven by key factors such as water resources, human health, infrastructure, and disaster prevention. Notably, indicators such as the green coverage rate, cultivated land area, and health technician availability emerged as critical contributors to adaptive capacity. This research highlights a strategic shift towards technological-financial capacity and the strengthening of institutional frameworks. The research identifies key future priorities for enhancing urban adaptation, such as increasing green space, improving water resource management, and strengthening health systems. Furthermore, we discuss the regional coordination climate change adaptation capacity in Chongqing and Chengdu, policy recommendations, and adaptation funding allocation recommendations. The research pioneers an integrated evaluation system for urban adaptive capacity assessment, thereby contributing innovative decision-support for cities seeking to strengthen their adaptive capacity.