Widespread loss of lake ice around the Northern Hemisphere in a warming world

Ice provides a range of ecosystem services, including fish harvest, cultural traditions, transportation, recreation, and regulation of the hydrologic cycle, to more than half of the world's 117 million lakes. One of the earliest observed impacts of climatic warming has been the loss of freshwater ice, with corresponding climatic and ecological consequences. However, while trends in ice cover phenology have been widely documented, a comprehensive large-scale assessment of lake ice loss is absent. Here, using observations from 513 lakes around the Northern Hemisphere, we identify lakes vulnerable to ice-free winters. Our analyses reveal the importance of air temperature, lake depth, elevation, and shoreline complexity in governing ice cover. We estimate that 14,800 lakes currently experience intermittent winter ice cover, increasing to 35,300 and 230,400 at 2degC and 8degC, respectively, impacting up to 394 and 656 million people. Our study illustrates that an extensive loss of lake ice will occur within the next generation, stressing the importance of climate mitigation strategies to preserve ecosystem structure and function, as well as local winter cultural heritage.

全球1.17亿个湖泊中，逾半数可从湖冰中获取多种生态系统服务，涵盖渔业捕捞、文化传承、交通运输、休闲娱乐以及水文循环调控。气候变暖最早被观测到的影响之一即为淡水冰消退，并伴随相应的气候与生态连锁反应。尽管冰盖物候（ice cover phenology）的变化趋势已被大量文献记录，但目前仍缺乏针对湖冰消退的全面大规模评估。本研究依托北半球513个湖泊的观测数据，筛选出冬季易出现无冰状态的脆弱湖泊。分析结果表明，气温、湖泊水深、海拔与岸线复杂度是调控湖冰覆盖的核心影响因素。我们估算，当前共有1.48万个湖泊的冬季冰盖呈现间歇性覆盖状态；在升温2℃与8℃的情景下，该数值将分别增至3.53万个与23.04万个，受影响人口最多可达3.94亿与6.56亿。本研究揭示，未来数十年内全球湖冰将出现大面积消退，凸显了气候减缓策略对于保护生态系统结构与功能、以及当地冬季文化遗产的重要意义。