Climate change, glacier retreat and glacial lake outburst floods (GLOFs) are intertwined. The Cordillera Blanca in Peru has one of the world's longest GLOF records and here we assess the evolution of glacial lakes in the region between 1948 and 2017 and investigate the links to documented GLOFs. We also model future lake evolution under two climate scenarios to provide an assessment of current and future GLOF triggering potential. Our analysis shows that the number of lakes as well as the total lake area has increased during the historical period. The formation of new lakes is, however, not uniform among different lake types with bedrock-dammed lakes exhibiting the largest increase in recent decades. We argue that moraine-dammed lakes have already formed at the majority of potential locations in the Cordillera Blanca and that the next generation of lakes which are expected to form in response to glacier retreat over topographically suitable areas will be predominantly bedrock-dammed. Based on a regional GLOF inventory, we show that the peak frequency of GLOFs occurred from the late 1930s to early 1950s. While GLOFs originating from moraine-dammed lakes dominated in this period, recent GLOFs have originated from bedrock-dammed lakes. At the same time, the majority of GLOFs originated from lakes in a proglacial phase (i.e. in contact with glacier), even though the share of proglacial lakes did not exceed 12% at any time step during the analysed period. While many moraine-dammed lakes evolved into the glacier-detached evolutionary phase, bedrock-dammed lakes became a major lake dam type among proglacial lakes. Over the remainder of the 21st century, a further increase in lake area of up to 10% is anticipated, with up to 50 new bedrock dammed lakes likely to develop as glaciers retreat. There is little difference in lake development and GLOF triggering potential under climate scenarios driven by RCP 2.6 and 8.5. Based on topographic disposition, recent and future lakes do not individually appear more or less susceptible to landslide impact than lakes that already developed earlier in the 20th century. Synthesizing these findings, we forecast that bedrock-dammed lakes will become the dominant source of GLOFs in the next decades. Because such dams are inherently more stable, we expect overall lower GLOF magnitudes compared to documented GLOFs from moraine-dammed lakes.

中文翻译：

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科迪勒拉布兰卡（秘鲁）70 年的湖泊演变和冰川湖溃决洪水及其对未来的影响

气候变化、冰川退缩和冰川湖溃决洪水 (GLOF) 相互交织。秘鲁的 Cordillera Blanca 拥有世界上最长的 GLOF 记录之一，在这里我们评估了 1948 年至 2017 年该地区冰川湖的演变，并调查了与记录的 GLOF 之间的联系。我们还对两种气候情景下的未来湖泊演变进行了建模，以评估当前和未来的 GLOF 触发潜力。我们的分析表明，在历史时期，湖泊数量和湖泊总面积都有所增加。然而，新湖泊的形成在不同湖泊类型之间并不统一，近几十年来基岩堰塞湖的增加幅度最大。我们认为，Cordillera Blanca 的大多数潜在位置已经形成了冰碛堰塞湖，预计在地形合适的地区因冰川退缩而形成的下一代湖泊将主要是基岩堰塞湖。基于区域 GLOF 清单，我们表明 GLOF 的峰值频率发生在 1930 年代末至 1950 年代初。虽然起源于冰碛堰塞湖的 GLOF 在这一时期占主导地位，但最近的 GLOF 起源于基岩堰塞湖。同时，大部分 GLOF 起源于处于前冰期（即与冰川接触）的湖泊，即使在分析期间的任何时间步长内，前冰期湖泊的份额都不超过 12%。当许多冰碛湖演化到冰川分离演化阶段时，基岩堰塞湖成为冰河期湖泊中的主要湖坝类型。在 21 世纪的剩余时间里，预计湖泊面积将进一步增加 10%，随着冰川退缩，可能会形成多达 50 个新的基岩堰塞湖。在 RCP 2.6 和 8.5 驱动的气候情景下，湖泊开发和 GLOF 触发潜力几乎没有差异。根据地形配置，与 20 世纪早期已经开发的湖泊相比，近期和未来的湖泊不会单独出现或多或少地容易受到滑坡影响。综合这些发现，我们预测基岩堰塞湖将成为未来几十年 GLOF 的主要来源。由于此类大坝本质上更稳定，因此与来自冰碛堰塞湖的记录 GLOF 相比，我们预计整体 GLOF 量级较低。