## 5 Conclusions  
In this study, we have investigated the exposing process of englacial debris of the Qiyi Glacier from 1972 to 2022 and its potential hydrological influences based on the satellite data and UAV images of meter/sub-meter resolutions. Our results indicate that with the ongoing climate warming, the enhanced ice melt would be offset by the sealing effect from emerging englacial debris on the clean-surface of the Qiyi Glacier, which will elongate the life expectancy of the glacier and mitigate glacial runoff risk in the near future. Our results also suggest that under the context of continuing climate warming, the transition from a clean surface to a debris-covered glacier is not confined to the large mountain glaciers (e.g., Herreid and Pellicciotti [18]), and is also possible for small glaciers (such as the Qiyi glacier) when certain conditions prevail. We believe that the Qiyi Glacier must not be the only glacier nor the first glacier that is showing an expanding trend of debris, but only the first one where this process has been witnessed with regular in situ observations, and we believe that similar cases will be reported elsewhere on the Tibetan Plateau in future with continuing global warming.  
Generally, climatic factors are thought to be the main driving forces of clean surface glacier and glacial runoff changes, whereas intra-glacier feedbacks are often neglected. The emerging englacial debris on the Qiyi Glacier suggests that glacier dynamics must be considered when modeling future glacier and glacial runoff changes. Moreover, the receding and thinning mountain glaciers may trigger anomalous ice mass loss (e.g., ice disintegration; see Figures 4a and S2) at more frequent intervals, which will complicate the glacier system even further [7]. Currently, the increasingly available fine-scale remote sensing data at sub-meter resolution (such as the multi-satellite constellations and microsatellites as well as the UAV) allows us to evaluate how mountain glaciers are responding to a warming climate [28], and this will enhance our understanding of glacier evolution and its hydrological impacts.  
The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/rs15153899/s1](https://www.mdpi.com/article/10.3390/rs15153899/s1)]([https://www.mdpi.com/article/10.3390/rs15153899/s1](https://www.mdpi.com/article/10.3390/rs15153899/s1)): Figure S1: Exposed englacial debris in five zones A-E (a-e, respectively; taken on summer 2022); Figure S2: Ice disintegration in the terminus of the Qiyi Glacier that was first observed on summer 2013. a: ice crevasse; b: ice disintegration from the ice crevasse.  
Conceptualization, Y.W., W.Z. and S.Z.; methodology, Y.W., Z.M. and Q.Z.; software, Y.W. and Z.M.; validation, Y.W., Z.L. and Z.M.; formal analysis, Y.W. and A.C.; investigation, Z.M. and Z.G.; resources, Z.L.; data curation, Z.M., A.C. and Y.L.; writing--original draft preparation, Y.W. and W.Z.; writing--review and editing, Y.W.; visualization, Z.G. and X.J.; supervision, S.Z.; project administration, Y.W. and S.Z.; funding acquisition, Y.W. and S.Z. All authors have read and agreed to the published version of the manuscript.  
This research was supported in part by the National Natural Science Foundation under Grants 42171139, 42130516, 42171124, and 41871053 and in part by the Strategic Priority Research Program of the Chinese Academy of Sciences under Grants XDA20070100.  
**Data Availability Statement:** The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy.  
**Acknowledgments:** Special thanks are given to [PERSON] for helpful comments and discussions. We also thank [PERSON] for supplying field photos of Qiyi Glacier.  
**Conflicts of Interest:** The authors declare no conflict of interest.