Bavarian alpinist and researcher Gottfried Merzbacher discovered an ice-dammed lake in 1903 while trying to reach the mysterious Khan Tengri peak, located where Kyrgyzstan, Kazakhstan, and China meet. This lake, which was later named after him, is currently two lakes in the Northern Inylchek Valley. At an altitude of 3300 m and 3400 m above sea level (a.s.l.), these two lakes are known as Lower Lake Merzbacher and Upper Lake Merzbacher. Lower Lake Merzbacher is dammed by the Southern Inylchek Glacier and has had regular outbursts since the beginning of the 20th century. While these outbursts have been sporadically documented since 1902, neither the documentation nor the reliability of the reports has been consistent. Knowledge of many of the floods is known only from the oral or written contributions of mountaineers, glaciologists, and frontier guards. A small number of floods were measured at gauging stations downstream. Since it was not always recognized that these floods were the results of glacier lake outbursts, not many papers on this subject have been published in German, English or Russian journals. There were about 40 outbursts reported between 1902 and 2004, but only a few of them were eye witnessed. A number of geoscientific expeditions investigated glacier retreat and the mechanism of the (lower) lake’s outburst through an englacial piping system of the Southern Inylchek Glacier. As the Inylchek River flows into the Tarim Basin, the flood waves endanger not only Kyrgyzstan but also China. This paper gives a short overview on the mechanism, magnitude, repetition rate and timing of Lake Merzbacher’s outbursts. Of particular interest is the discovery that the outbursts have shifted statistically significantly, namely from September/October in the first half of the century to July/August in last few decades. It is presumed that this is due to the climate change. Future research on the impact of climate change on the Upper Inylchek Valley is supported by the Global Change Observatory “Gottfried Merzbacher”, which opened in 2009 and was jointly planned by the Central Institute of Applied Geosciences (CAIAG, Bishkek, Kyrgyz Republic) and the German Research Center Potsdam (GeoForschungsZentrum – GFZ-Potsdam, Germany). The installation of ablation gauges, planned ice core drilling, and hydrometeorologic and seismologic stations will make it possible to assess the climatic and neotectonic development of the Central Tien Shan in general and to calculate the mass balance and quantification of the partly retreating Southern Inylchek Glacier in particular. This article “A Century of Investigations on Outbursts of the Ice-Dammed Lake Merzbacher” briefly summarizes observations and research conducted since 1903 and also documents the lake’s regular outbursts.