Comprehensive Risk Assessment of Sea Level Rise and Tropical Cyclones in Dongzhaigang Mangroves, China

Mangroves play a pivotal role in tropical and subtropical coastal ecosystem, yet they are highly vulnerable to the effects of climate change, particularly the accelerated global sea level rise (SLR) and stronger tropical cyclones (TCs). However, there is a lack of research addressing future simultaneous combined impacts of the slow-onset of SLR and rapid-onset of TCs on China’s mangroves. In order to develop a comprehensive risk assessment method considering the superimposed effects of these two factors and analyze risk for mangroves in Dongzhaigang, Hainan Island, China, we used observational and climate model data to assess the risks to mangroves under low, intermediate, and very high greenhouse gas (GHG) emission scenarios (such as SSP1-2.6, SSP2-4.5, and SSP5-8.5) in 2030, 2050, and 2100, and compiled a risk assessment scheme for mangroves in Dongzhaigang, China. The results showed that the combined risks from SLR and TCs will continue to rise; however, SLRs will increase in intensity, and TCs will decrease. The comprehensive risk of the Dongzhaigang mangroves posed by climate change will remain low under SSP1-2.6 and SSP2-4.5 scenarios by 2030, but it will increase substantially by 2100. While under SSP5-8.5 scenario, the risks to mangroves in Dongzhaigang are projected to increase considerably by 2050, and approximately 68.8% of mangroves will be at very high risk by 2100. The risk to the Dongzhaigang mangroves is not only influenced by the hazards but also closely linked to their exposure and vulnerability. We therefore propose climate resilience developmental responses for mangroves to address the effects of climate change. This study for the combined impact of TCs and SLR on mangroves in Dongzhaigang, China can enrich the method system of mangrove risk assessment and provide references for scientific management.