Lakes hold much of Earth’s accessible liquid freshwater, support biodiversity and provide key ecosystem services to people around the world. However, they are vulnerable to climate change, for example through shorter durations of ice cover, or through rising lake surface temperatures. Here we use a one-dimensional numerical lake model to assess climate change impacts on mixing regimes in 635 lakes worldwide. We run the lake model with input data from four state-of-the-art model projections of twenty-first-century climate under two emissions scenarios. Under the scenario with higher emissions (Representative Concentration Pathway 6.0), many lakes are projected to have reduced ice cover; about one-quarter of seasonally ice-covered lakes are projected to be permanently ice-free by 2080–2100. Surface waters are projected to warm, with a median warming across lakes of about 2.5 °C, and the most extreme warming about 5.5 °C. Our simulations suggest that around 100 of the studied lakes are projected to undergo changes in their mixing regimes. About one-quarter of these 100 lakes are currently classified as monomictic—undergoing one mixing event in most years— and will become permanently stratified systems. About one-sixth of these are currently dimictic—mixing twice per year—and will become monomictic. We conclude that many lakes will mix less frequently in response to climate change.

湖泊拥有地球上大部分可利用的液态淡水，支持生物多样性并为世界各地的人们提供关键的生态系统服务。但是，它们很容易受到气候变化的影响，例如由于冰覆盖时间的缩短或湖面温度的升高。在这里，我们使用一维数值湖泊模型来评估气候变化对全球635个湖泊的混合状态的影响。我们使用来自两种排放情景下二十一个世纪气候的四个最新模型预测的输入数据来运行湖泊模型。在排放量较高的情况下（代表性浓度途径6.0），预计许多湖泊的冰盖减少；预计到2080年至2100年，约有四分之一的季节性冰雪覆盖的湖泊将永久无冰。预计地表水会变暖，整个湖泊的平均升温约为2.5°C，最极端的升温约为5.5°C。我们的模拟表明，预计大约有100个受研究的湖泊将经历其混合制度的变化。在这100个湖泊中，目前约有四分之一被归类为单项湖泊-在大多数年份中经历了一次混合事件-并将成为永久分层的系统。目前，其中约有六分之一是单声道的，每年混合两次，并且将变成单声道的。我们得出的结论是，由于气候变化，许多湖泊的混合频率会降低。在这100个湖泊中，目前约有四分之一被归类为单项湖泊-在大多数年份中经历了一次混合事件-并将成为永久分层的系统。目前，其中约有六分之一是单声道的，每年混合两次，并且将变成单声道的。我们得出的结论是，由于气候变化，许多湖泊的混合频率会降低。在这100个湖泊中，目前约有四分之一被归类为单项湖泊-在大多数年份中经历了一次混合事件-并将成为永久分层的系统。目前，其中约有六分之一是单声道的，每年混合两次，并且将变成单声道的。我们得出的结论是，由于气候变化，许多湖泊的混合频率会降低。