The climate change of the twentieth century had a pronounced effect on glacier environments of the Himalaya. The formation of supraglacial lakes and moraine dammed glacial lakes and glacial lake outburst flood is a major concern in countries such as Bhutan, China (Tibet), India, Nepal and Pakistan. This article depicts a semi-automated identification of glacial lakes in the Sikkim Himalaya, from the normalised difference water index-based methodology of Resourcesat-1 LISS III satellite data. The inventory shows the existence of 320 glacial lakes out of which 85 are new ones in the study area compared to 2003 inventory. Remote sensing proves to be the best tool in detecting and monitoring the hazardous nature of glacial lakes in the Indian Himalaya. To establish the hazard potential of glacial lakes, a systematic inventory of these lakes from high-resolution satellite data and in situ field survey is recommended.

Deglaciation has led to the transformation of glaciers into rock glaciers in various mountainous regions worldwide. However, the science of permafrost and rock glaciers remains under‐researched in the Himalayan region. This study presents a detailed inventory, dynamics, and permafrost distribution map for the Jhelum basin in the Kashmir Himalaya. The Permafrost Zonation Map (PZM) is created using a Logistic Regression Model based on topographic and climatic variables. High‐resolution satellite images are used to identify rock glaciers as visual indicators. Active and relic rock glaciers are classified based on surface topography and geomorphology. Results reveal 207 rock glaciers in the Jhelum basin, covering ∼50 km², with over 100 falling into the active category. The PZM aligns well with the global permafrost zonation index map. Slope, aspect, and elevation of rock glaciers are computed using the ASTER Digital Elevation Model. The average elevations range from 3,700 m to 4,550 m, and the average surface slope ranges from 12° to 26°, with maximum slopes from 25° to 65°. Most rock glaciers are oriented toward the south or southeast. Field investigations confirm that these rock glaciers occur in highly elevated regions with steep slopes. This study provides valuable information on the high areal abundance of permafrost in the Himalayan region and suggests increased risks of thawing permafrost due to climate warming in the future. The findings contribute to the understanding of permafrost and rock glaciers, filling knowledge gaps in the Himalayan context.

The Himalayan glaciers significantly contribute to the largest river systems like the Indus, Ganga, and the Brahmaputra. The change in glacial area and mass can affect the mountain community and people living in the Indo-Gangetic plain. The present study adopted the geodetic method to estimate the elevation change and mass budget of 61 glaciers in the Alaknanda Basin, using the satellite data of Cartosat-1 (2011, 2014, 2017) and SRTM (2000). Besides, the DEM of 1962 (SOI Toposheet) and 2000 (SRTM) is used to estimate the mass budget of Satopanth (SPG) and Bhagirath Kharak glaciers (BKG). The field debris thickness of SPG (2015-2017) is compared with the elevation change (2000-2017). Further, we have compared the mass loss of the glaciers with their volume. The results suggest the sustained mass loss of 1.85 ± 0.10 Gt out of 33.9 ± 8.8 Gt for 61 glaciers in the basin from 2000-2017. The mass loss of SPG and BKG during 2000-2017 is 0.20 ± 0.02 Gt and 0.24 ± 0.03 Gt, whereas from 1962 to 2000, is 0.083 ± 0.03 Gt and 0.091 ± 0.04 Gt, respectively. The analysis facilitates a better understanding of glacier mass changes in the Alaknanda basin on a multi-decadal scale.

Here we present a detailed analysis of glaciers in the Alaknanda Basin, Central Himalaya, starting with a novel glacier inventory for 1968 and 2020 using high-resolution datasets of Corona and Sentinel-2A. Primarily, we examine the factors influencing changes in glacier characteristics. Results show that glacier area reduced to 683 ± 47.81 km² from 742 ± 44.4 km², and the number of glaciers increased to 116 from 98 between 1968 − 2020. The annual average recession of glaciers in the basin is 11.75 ± 1.6 m/year for the corresponding period. Also noted is a significant increase (∼38%) in supraglacial debris cover extent of the glaciers during 2000–2020. Interestingly, smaller glaciers (< 5 km²) with lower altitude snout and higher slope have registered more significant area loss and higher retreat rate. Alongside topographic parameters, the significant deglaciation and fragmentation observed in the basin are augmented by the increase in winter-time temperature (0.03 °C/year) between 1968–2020.

Aim of the study: The value of fish resources to socioeconomic development is immense. However, there is growing evidence that loss of quality in the marine environments e.g. marine waters at sea and coastal freshwater zones is threatening the availability of livelihood resources e.g. fish resources evidenced by the dwindling fisheries resources that promote sustainable livelihood. Cognizant of this, several fisheries institutions, governments, and local users have come up with several strategies to boost marine water environment management and promote sustainable fishing. Unfortunately, most of the initiatives have not fully managed to repulse unsustainable practices e.g. marine water pollution that leads to loss of wild catches and leads to unsustainable fishing practices. Material and methods: Owing to this we use a mixed research methods approach involving a systematic literature review and field survey in Alappad to argue and present a case for governments and fishery management organizations to invest in data analytics as a new pathway that can give a comprehensive, near real-time view of both ocean resources and coastal fishing activities in light of the declining fish stocks and escalating environmental problems e.g. marine water quality loss e.g. due to pollution. Results and conclusions: Findings documented that by using data analytics, governments, and fisheries management organizations/individuals may respond more swiftly to external forces like climate change, and marine water quality loss and implement new policies and regulations thus promoting sustainable fisheries management. Local perspectives of coastal communities could also guide the best data analytics tool or method to be used.

Glacial lake outburst floods (GLOFs) are destructive and threaten downstream communities in the Himalaya. Through satellite image analysis, we investigate the 2023 GLOF event at South Lhonak Lake, Sikkim, India, focusing on the lake’s historical evolution and the geomorphic controls that caused the GLOF. Multi-temporal data from 10 satellite missions revealed a significant increase in glacier surface lowering from −0.19 m year ⁻¹ (1970–1983) to −0.87 m year ⁻¹ (2015–2023). Initially a supraglacial lake in 1962, it evolved into a moraine-dammed lake by 1983 and expanded 12-fold from 0.11 km ² (1962) to 1.4 km ² (2023). Between 27 September and 6 October 2023, satellite imagery revealed an unusually strong retreat of 49.6 ± 7.1 m, indicating glacier calving and presence of massive icebergs visible on the lake. Our analysis shows 7 large glacier retreat and calving events between 2017 and 2023, further weakening the lateral moraines. This, combined with intermittent rainfall triggered the moraine dam collapse, leading to the GLOF. These findings emphasize the need for long-term monitoring of Himalayan glacial lakes.