The study examines the spatiotemporal distribution of glacial lakes and the factors influencing their changes on the Southeastern Tibetan Plateau from 1993 to 2023. This region, primarily characterized by marine-type glaciers, houses glacial lakes highly sensitive to global climate change.
According to the research utilizing Google Earth Engine (GEE) data and meteorological information, southeastern Tibet is projected to have 3,877 glacial lakes by 2023, covering approximately 395.74 ± 22.72 km2. The findings highlight significant spatial distribution patterns, with higher concentrations of glacial lakes found in the southern region compared to the northern region. Glacial lakes smaller than 0.1 km2 constitute 94.24% of these lakes, with larger lakes showing minimal changes.
The study employs advanced methods, including the FCN model, to accurately delineate glacial lake boundaries. The analysis reveals fluctuated annual mean precipitation and average annual temperature, with both elements decreasing since 2008. Despite this decline, the number and area of glacial lakes remain relatively stable. The research indicates the proliferation of glacial lakes may accelerate, particularly in the eastern and western regions of Nyingchi City, driven by slight increases in precipitation and rising temperatures.
Glacial lakes are formed primarily by glacier melting, with their distribution influenced by various factors such as elevation, climate, and geology. The area encompassed by these lakes has seen steady growth, which poses flood risks due to potential glacial lake outburst floods (GLOFs) — catastrophic events triggered by the sudden release of water from glacial lakes. Even though the frequency of such outbursts has remained fairly consistent, the increased sizes of glacial lakes heighten the risk of devastating floods affecting infrastructure and local communities.
Historical data suggests the Qinghai-Tibet Plateau, which features the world’s highest concentration of glaciers outside the polar regions, has experienced significant changes due to rising temperatures. Specifically, research confirms alarming glacial mass loss rates and retreats, particularly affecting the area around Nyingchi and Qamdo, where marine glaciers are predominant.
To assess these changes, the study employed remote sensing data from Landsat satellites and detailed meteorological data spanning three decades. The results indicate dramatic shifts; for example, between 1993 and 2023, the area of glacial lakes has expanded by 35.90 ± 4.74 km2, showing expansion rates of over 32%. While microglacial lakes are rapidly forming near retreating glaciers, the overall stability of larger lakes indicates complex dynamics at play.
Interestingly, the investigation aligns with previous research indicating the increased sensitivity of high-elevation glacial lakes to temperature fluctuations. The majority of these water bodies are located at elevations exceeding 4,442 m, where climate change exacerbates the melting of glaciers and influences the distribution of glacial lakes.
Areas such as Zayul have observed rapid glacial lake growth due to heightened precipitation feeding the ecosystems. Recent assessments suggest Zayul and Bomi regions are experiencing significant glacial lake expansions, prompting calls for active monitoring strategies and disaster preparedness measures. Understanding the dynamics affecting these lakes is imperative to safeguard local populations and infrastructure from the risks tied to climate-change-fueled disasters.
This comprehensive study not only highlights the pressing need for diligent tracking of glacial lake changes but also provides valuable insights for developing policies aimed at managing water resources, environmental protection, and minimizing disaster risks on the plateau.