Unprecedented rates of anthropogenic sea level rise (ASLR) and attendant wave‐driven flooding and salinization threaten the stability (and habitability) of atoll islands. Thus, there is doubt regarding the continued existence of sovereign atoll nations and unique, place‐based indigenous atoll cultures. Evidence that some atoll islands may have originally formed in the latter stages of post‐glacial sea level rise (SLR) has been interpreted to mean they will persist under accelerating ASLR. These forecasts are at odds with interpretations that atoll islands will succumb to rising seas. To shed light on conflicting models of island stability, we develop a multitemporal island vulnerability assessment (MIVA) to anticipate island instability and apply it in the Republic of the Marshall Islands (RMI) where there is a history of previous research. Using evidence from geological and historical records of island response to changing late Holocene sea level and modern tide, wave, and groundwater observations, we identify thresholds where islands pass from stable to unstable phases due to projected local, relative ASLR. Under the most likely scenario (intermediate‐high) where ASLR reaches 1.91 m by 2100, island stability deteriorates by midcentury as historical rates of SLR at RMI increase threefold, and temporary flood events deteriorate potable groundwater and agroforests. In the second half of the century, as ASLR exceeds geological sea level thresholds, permanent island instability will be inevitable with no action. We conclude that these islands are already trending into declining stability due to ASLR as documented by published observations of extreme tides, wave inundation, salinization, and sediment mobilization.

中文翻译：

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重新思考与人为海平面上升有关的礁岛稳定性

前所未有的人为海平面上升速率（ASLR）以及随之而来的波浪驱动的洪水和盐碱化威胁着环礁岛的稳定性（和可居住性）。因此，对于主权环礁国家和独特的，以地方为基础的土著环礁文化是否继续存在存在疑问。有证据表明某些环礁岛最初是在冰川后海平面上升（SLR）的后期形成的，这意味着它们将在加速的ASLR下持续存在。这些预测与环礁岛将屈服于海平面上升的解释相悖。为了阐明冲突的岛屿稳定模型，我们开发了多时岛屿脆弱性评估（MIVA）以预测岛屿的不稳定性，并将其应用在有先前研究历史的马绍尔群岛共和国（RMI）中。利用来自岛屿对新世晚期海平面变化的反应的地质和历史记录以及现代潮汐，波浪和地下水观测的证据，我们确定了由于预计的局部相对ASLR而使岛屿从稳定阶段过渡到不稳定阶段的阈值。在最有可能发生的情况（中高）下，ASLR到2100年将达到1.91 m，到本世纪中叶，由于RMI的SLR的历史速度增加了三倍，岛屿的稳定性将恶化，并且临时洪水事件会破坏饮用水和农林。在本世纪下半叶，随着ASLR超过地质海平面阈值，永久岛不稳定将不可避免，而无需采取任何措施。我们得出的结论是，由于发表了关于极端潮汐，海浪泛滥，盐碱化，