Sea-level rise will lead to widespread habitat loss if warming exceeds 2 °C, threatening coastal wildlife globally. Reductions in coastal habitat quality are also expected but their impact and timing are unclear. Here we combine four decades of field data with models of sea-level rise, coastal geomorphology, adaptive behaviour and population dynamics to show that habitat quality is already declining for shorebirds due to increased nest flooding. Consequently, shorebird population collapses are projected well before their habitat drowns in this UNESCO World Heritage Area. The existing focus on habitat loss thus severely underestimates biodiversity impacts of sea-level rise. Shorebirds will also suffer much sooner than previously thought, despite adapting by moving to higher grounds and even if global warming is kept below 2 °C. Such unavoidable and imminent biodiversity impacts imply that mitigation is now urgently needed to boost the resilience of marshes or provide flood-safe habitat elsewhere.

如果气温上升超过 2°C，海平面上升将导致大范围的栖息地丧失，从而威胁全球沿海野生动物。预计沿海栖息地质量也会下降，但其影响和时间尚不清楚。在这里，我们将四十年的实地数据与海平面上升、沿海地貌、适应性行为和种群动态模型结合起来，表明由于巢穴洪水增加，滨鸟的栖息地质量已经下降。因此，在这个联合国教科文组织世界遗产地区，鸻鹬类鸟类的栖息地被淹没之前，其种群数量就会急剧下降。因此，现有对栖息地丧失的关注严重低估了海平面上升对生物多样性的影响。尽管滨鸟通过迁徙到地势较高的地方进行了适应，并且即使全球变暖保持在 2°C 以下，但它们遭受苦难的时间也将比之前想象的要快得多。这种不可避免且迫在眉睫的生物多样性影响意味着现在迫切需要采取缓解措施，以增强沼泽的恢复能力或在其他地方提供防洪栖息地。