Journal Article

Climate Change‐Driven Long‐Term Stability Risks of Ubiquitous Moraine Dams in Glacial Lakes on Qinghai‐Tibet Plateau: A Multiphysics Coupling Evolution Perspective

Li, Qi‐Long, Chen, Yi‐Feng, Tang, Huiming, Jiao, Jiu Jimmy, Zhou, Jia‐Qing, Li, Changdong

2024

Overview

Glacial lake‐moraine dam systems are widespread in cold alpine environments such as the Qinghai‐Tibet Plateau (QTP). Without climate change, the lake‐dam system exhibits stably dynamic evolution on a hydrological annual cycle. However, climate change may drive subtle alterations in the system's evolution. We developed a fully coupled Thermal‐Hydraulic‐Mechanical simulation platform considering ice‐water phase change, showing robust performance under CMIP6‐derived boundary conditions. Using this platform, we simulated climate warming‐driven multiphysics responses and dam stability evolutions of a homogeneous, simplified conceptual model of the lake‐dam system. We identified critical temperature thresholds for permanently frozen area thawing and abrupt changes in dam stability of this lake‐dam system. Considering the current slope stability situations on the QTP, the SSP 5–8.5 climate warming scenario is conservatively anticipated to pose significant geological safety risks due to potential disaster chains from glacial lake failures. Our study provides insights into profound geological process evolutions driven by climate change. Plain Language Summary Sizable and numerous moraine‐dammed glacial lakes in cold alpine regions are increasingly threatened by climate change. This study simulated the long‐term (2020–2140) Thermal‐Hydraulic‐Mechanical coupling and stability evolution of a homogeneous conceptualized glacial lake‐moraine dam system under climate warming on the Qinghai‐Tibet Plateau (QTP). Two types of critical state‐transition points were identified in this conceptual model, marking shifts from quantitative to qualitative changes. A temperature rise threshold of 5.89°C indicates the onset of rapid shrinkage in permanently frozen area of the conceptual lake‐dam system. Another type of transition points occurs at 1.92°C and 4.48°C, corresponding to sharp year‐over‐year declines in spring and winter stability, respectively. A conservative estimation suggests that, if evaluated using stability reduction rate of the conceptualized model, moraine dams on the QTP with current stability factors below 1.19 in summer or 1.81 in winter, could fail after 120 years of intense climate warming. Considering the current stability situations on the QTP and geohazard chains resulting from glacial lake failure, uncontrolled global climate change would pose a severe threat to regional geological safety of QTP. The study has significant implications for assessing geological safety in periglacial environments and supports investigating coupling issues of climate change, geological processes, and human activities. Key Points Climate change‐driven multiphysics responses and stability evolution of a conceptual glacial lake‐moraine dam are depicted over the next 120 years Frozen area would rapidly retreat for nearly 10 years once the temperature rise crosses a certain threshold (5.89°C for the conceptual model) Spring and winter stability would rapidly deteriorate after surpassing certain temperature thresholds (1.92°C and 4.48°C, respectively, for the model)

• Publisher: John Wiley & Sons, Inc,Wiley
• Subject: Alpine environments / Alpine regions / Annual variations / Boundary conditions / Climate change / Coupling / Critical temperature / Dam stability / Dams / Evolution / Geological hazards / Geological processes / Geology / Glacial drift / Glacial lake outburst floods / Glacial lakes / Global climate / Global warming / Hydrologic cycle / long‐term stability / Mechanical properties / Moraines / moraine‐dammed glacial lake / Plateaus / Qinghai‐Tibet Plateau / Safety / Slope stability / Stability analysis / Temperature rise / Thawing / Thermal simulation / THM coupling / Transition points / Winter