The accurate quantification of uncertainties in regional sea‐level projections is essential for guiding policy makers. As climate models do not currently simulate total sea level, these uncertainties must be quantified through summation of uncertainties in individual sea‐level components. This summation depends on the correlation between the components, which has previously been prescribed or derived from each individual component's dependence on global mean surface temperature. In this study, we quantify, for the first time, regional correlations between sea‐level components based on regional climate change projections. We compute regional sea‐level projections consistent with climate projections from an ensemble of 14 Earth System Models. From the multi‐model spread, we estimate the uncertainty in the regional climate's response to greenhouse forcing. To quantify the total uncertainty, we add the uncertainty in the response of sea‐level components to this regional climate change. This approach reveals how regional climate processes impose correlations between sea‐level components, affecting the total uncertainty. One example is an anti‐correlation between North Atlantic sterodynamic change and Antarctic dynamic mass loss, suggesting a teleconnection established by the large‐scale ocean circulation. We find that prescribed correlations, applied in the fifth assessment report of the Intergovernmental Panel on Climate Change, lead to a global overestimation in the uncertainty in regional sea‐level projections on the order of 20%. Regionally, this overestimation exceeds 100%. We conclude that accurate uncertainty estimates of regional sea‐level change must be based on projections of regional climate change and cannot be derived from global indicators such as global mean surface temperature.

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区域气候变化驱动海平面要素之间的相关性

准确量化区域海平面预测中的不确定性对于指导决策者至关重要。由于气候模型目前尚无法模拟总海平面，因此必须通过汇总各个海平面分量的不确定度来量化这些不确定度。该总和取决于组件之间的相关性，该相关性先前已被规定或从每个单个组件对全局平均表面温度的依赖性中得出。在这项研究中，我们首次基于区域气候变化预测来量化海平面分量之间的区域相关性。我们从14个地球系统模型的集合中计算出与气候预估一致的区域海平面预估。通过多模型传播，我们估计区域气候的不确定性。对温室强迫的反应。为了量化总不确定性，我们在海平面分量对该区域气候变化的响应中添加了不确定性。这种方法揭示了区域气候过程如何在海平面分量之间施加相关性，从而影响总不确定性。一个例子是北大西洋的气动力变化与南极动力质量损失之间的反相关关系，这表明由大规模海洋环流建立的遥相关。我们发现，政府间气候变化专门委员会第五次评估报告中采用的规定的相关性导致全球对区域海平面预测的不确定性高估了20％左右。在区域上，这种高估超过100％。