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It is widely believed that global mean sea-level (GMSL) rise primarily affects coastal regions, causing floods, beach erosion, and community displacement. However, our recent two studies suggest that its influence extends far beyond the coastlines, exerting significant effects on the global climate system.
In 2023, we employed a paleoclimate modeling approach to investigate the climatic consequences of GMSL rise by uniformly increasing sea level across the globe, without accounting for variations in relative sea level. Although this approach is idealized, incorporating sea-level changes substantially reduced model – data mismatches in our last interglacial experiments, highlighting the importance of this factor.
Our study further revealed that even modest increases in GMSL – on the order of several tens of centimeters – can reorganize large-scale atmospheric and oceanic circulation. Importantly, the study suggested the Bering Sea and Southern Ocean are critical regions for monitoring and understanding the climatic impacts of future GMSL rise.
The new results demonstrated that higher sea levels amplify both the intensity and frequency of extreme cold events in East Asia. Although overall cold extremes are projected to decline under global warming, sea-level rise acts as an important feedback mechanism that can enhance the risk of severe cold events.
Fluctuations in relative sea level may also play a crucial role, yet this aspect remains insufficiently understood. Capturing these effects will require the development of next-generation climate models capable of dynamically representing sea-level feedbacks within the coupled Earth system.
As sea levels continue to climb, new and unforeseen extremes may emerge. Our findings underscore the urgent need to reassess global disaster risks arising from sea-level rise and to plan for a future that extends far beyond the coastlines.
Sourse: Nature