The Arctic cryosphere is changing rapidly due to global warming. Northern Svalbard is a warming hotspot with a temperature rise of ~ 6 °C over the last three decades. Concurrently, modelled data suggest a marked increase in glacier runoff during recent decades in northern Svalbard, and runoff is projected to increase. However, observational data from before anthropogenic influence are sparse and the potential effects on the surface ocean are unclear. Here, we present a 200-year record of Ba/Ca ratios measured in annual increment-forming coralline algae from northern Spitsbergen as a proxy for past glacier-derived meltwater input. Our record shows a significant increasing trend in algal Ba/Ca ratios from the late-1980s onwards matching modelled regional runoff data, suggesting a drastic increase in land-based runoff. The rate of increase is unprecedented during the last two centuries and captures the impact of amplified warming on the coastal surface ocean in the high Arctic. The algal Ba/Ca runoff proxy offers an opportunity to reconstruct past land-based runoff variability in Arctic settings in high resolution, providing important data for validating and improving climate modelling studies.

由于全球变暖，北极冰冻圈正在迅速变化。斯瓦尔巴群岛北部是一个变暖的热点，在过去的三十年中温度上升了约6°C。同时，模型数据表明，在斯瓦尔巴群岛北部，近几十年来冰川径流明显增加，预计径流将增加。然而，来自人为影响之前的观测数据稀疏，对地表海洋的潜在影响尚不清楚。在这里，我们提供了200年记录的Ba / Ca比率记录，该记录是从Spitsbergen北部形成的逐年形成的藻类藻类中测得的，作为过去冰川衍生的融水输入的替代物。我们的记录显示，从1980年代后期开始，与模型化的地区径流数据相匹配的藻类Ba / Ca比值呈显着上升趋势，这表明陆基径流急剧增加。在过去的两个世纪中，这种增长速度是空前的，并捕捉到了变暖对北极高海拔沿海表层海洋的影响。藻类Ba / Ca径流替代物提供了一个机会，可以高分辨率重建北极地区过去的陆基径流变异性，为验证和改进气候模拟研究提供重要数据。