## 5 Conclusions  
In this study, we have illustrated the future opportunities and challenges on water resources that the SAM will face as a result of rapid cryospheric changes under a warmer climate. The SAM, which is located in the arid to semi-arid region of central Asia and is strongly influenced by the cryosphere, was selected as the research area to explore historical cryospheric changes and their potential effects on regional water resources and socio-economic environments. There have been general trends in increased warming and precipitation since the 1960s in the SAM. Both the temperature and precipitation have risen over each year, with winter exhibiting the greatest increases. There has been a general decrease in the extent of the cryosphere, although there has also been an abnormal increase in snow cover. These snow cover variations are represented by increased fluctuations in the maximum snow thickness and stable duration of the snow cover, with the onset of snowmelt occurring earlier. The freezing duration of SFG has followed a declining trend, with an approximate 33-day reduction in its duration and a mean shrinking rate of the annual maximum frozen depth of 5.8 cm/10 yr. Both the duration and maximum thickness of river ice have also decreased rapidly. The average duration and maximum thickness of river ice declined by 16.5 days and 30.0 cm, respectively, from the 1980s to 2000s, and the mean rate of decrease in ice duration, of 12.7 days for every 1 \({}^{\circ}\)C increase in air temperature, was twice the global mean. There was also a 32.75% loss in the number of mountain glaciers, with a 35.78% decline in the SAM glacier area between the 1960s and 2000s. Figure 8: Direct and cascading effects of cryospheric changes and their correlation with SDGs in the SAM. Numerous challenges on water resources related to historical cryospheric changes have been identified in the SAM. Earlier snowmelt caused by rapid spring warming has led to the redistribution of annual surface runoff, which is now characterized by an increase in spring runoff and a decrease in summer runoff, and has further widened the time gap between water supply and demand. Dramatic interannual changes in cryospheric meltwater caused by variations in winter snow accumulation are a key source of risk in the region and may lead to more frequent snow-induced flooding and drought periods. These annual and interannual variations in cryospheric meltwater pose challenges to the hydropower generation, agriculture, livestock, fisheries, and tail-end lake environments. The potential benefits derived from the cryosphere meltwater represent either a direct or indirect control on the realization of regional SDGs in the SAM, including SDG1, SDG2, SDG6, SDG7, SDG11, SDG14, and SDG15, with snow cover forming the key component of any sustainable environmental protection or socio-economic activity. Further expansion of the regulation capacity of the reservoirs as well as increased international cooperation in transboundary areas, will be important adaptive strategies under a warming climate if we are to meet the challenges presented by cryospheric changes in this region. Conceptualization, W.Z. and Y.S. ; methodology, W.Z. ; writing--original draft preparation, W.Z. and A.C.; writing--review and editing, W.Z. and X.W. ; supervision, Y.S. ; funding acquisition, W.Z., Y.S., A.C. and X.W. All authors have read and agreed to the published version of the manuscript. This study was funded in part by the National Science Foundation of China [41971083], National Key R&D Program of China [2019 YFC1510501, 2019 YFC1510502] and National Science Foundation of China [41801035, 42071091]. Funding was also provided by State Key Laboratory of Cryospheric Science [SKLCS-ZZ-2022] and the Foundation for Excellent Youth Scholars of Northwest Institute of Eco-Environment and Resources, CAS. Not applicable. The authors are sincerely grateful to the anonymous reviewers for their suggestions and feedback, which helped improve the paper significantly.