1566. Intensifying Water-related Disasters and Climate Risks in Asia: Background and Preparedness Based on WMO Reports

In August 2026, heavy rainfall caused damage in many parts of Japan. Around the border between Nepal and the Tibet Autonomous Region of China, a debris flow and flood also occurred, possibly associated with a rapid slope failure involving a glacier, causing extensive damage to downstream settlements and infrastructure. The U.S. Geological Survey (USGS) reported that the event may have been caused by a slope failure involving a glacier near Langtang National Park in Nepal and that the resulting debris flow and flood may have travelled approximately 100 km. However, information, including the mechanism of the event, may be updated through future investigations.

Water-related disasters take many forms, including floods, sediment disasters, droughts, water shortages, and glacial lake outburst floods (GLOFs). These events directly affect human lives, livelihoods, agricultural production, and water resource management.

This article reviews two reports by the World Meteorological Organization (WMO) and places water-related disasters in the broader context of global and regional changes in climate and water resources. The first part focuses on the State of Global Water Resources 2021, which examines changes in global water resources, while the second part introduces the State of the Climate in Asia 2025, which summarizes climate conditions in Asia.

Changes in Global Water Resources: WMO’s State of Global Water Resources 2021

Published by WMO in November 2022, the State of Global Water Resources 2021 was the first edition of an annual report series launched to assess the impacts of climate, environmental, and societal change on the Earth’s water resources. In the report, WMO highlighted river discharge, major floods and droughts, changes in terrestrial water storage, and the importance and vulnerability of the cryosphere, underscoring the need for continuous monitoring and management of global freshwater resources.

According to the report, in 2021, under precipitation patterns influenced by climate change and La Niña conditions, many parts of the world experienced drier-than-average conditions. Compared with the hydrological average over the previous 30 years, the area with below-average river discharge was approximately twice as large as the area with above-average discharge. WMO also noted, citing information from UN-Water, that 74% of natural disasters that occurred between 2001 and 2018 were water-related. The report emphasized the need to position water as a central issue in climate change adaptation, while also pointing to the lack of available and verified hydrological data as a major challenge.

Climate and Water-related Risks in Asia: WMO’s State of the Climate in Asia 2025

Released by WMO on 17 June 2026, the State of the Climate in Asia 2025 summarizes conditions related to temperature, precipitation, oceans, glaciers, sea level, and extreme weather in Asia. WMO reported that in 2025, dangerous heat, heavy rainfall and floods, severe drought, and dust storms occurred across the region, causing substantial impacts on lives and economies.

According to the report, Asia’s annual mean temperature in 2025 was 0.96°C above the 1991–2020 average. While rankings vary depending on the dataset used, 2025 was assessed as the second- to fourth-warmest year on record. WMO reported that the warming trend in Asia during 1991–2025 was roughly twice that of 1961–1990, and that in recent years Asia has been warming faster than the global land and ocean average.

Regarding precipitation, WMO reported that in 2025 much of South Asia experienced above-normal rainfall, and exceptional monsoon rainfall led to flood damage. In contrast, parts of West Asia and Central Asia experienced below-normal precipitation and prolonged dry conditions, giving rise to concerns over water shortages.

In High Mountain Asia, all 23 glaciers observed during the 2025 glaciological year (October 2024 to September 2025) showed mass loss. WMO reported that below-normal winter snowfall and sustained high temperatures from May to September contributed to substantial glacier mass loss, particularly in the Tien Shan mountains and the Pamir Plateau.

WMO explains that glacier melt affects sea levels, regional hydrological cycles, and localized hazards such as GLOFs. It also reported that several GLOFs and glacier collapses were recorded in 2025. Glacier retreat and melt should therefore be understood not only as an issue affecting future water resource availability, but also as a disaster risk that can cascade from mountainous areas to downstream regions.

Preparedness for Water-related Risks

Asia is home to dense populations, and agricultural production, food supply, domestic water use, and industrial activities in the region depend heavily on water resources. Heavy rainfall, floods, sediment disasters, droughts, water shortages, and hazards associated with glacier melt should not be viewed merely as separate phenomena. Rather, they need to be understood as compound risks arising from overlapping factors, including the climate system, the water cycle, land use, the distribution of populations and assets, and the vulnerability of social infrastructure.

WMO emphasizes the importance of strengthening observation systems, enhancing early warning systems, impact-based forecasting, coordination among relevant institutions, and early action. In particular, it notes that reducing damage requires warnings to be issued promptly, delivered in ways that are trusted by residents, and reliably communicated to vulnerable people.

Recent water-related disasters show that the impacts of climate change are not only a future concern, but are already emerging through people’s daily lives, infrastructure, agriculture, and water resources in different regions. In light of WMO reports and recent disaster events, risks related to water should be addressed as cross-cutting issues spanning climate change, disaster risk reduction, agriculture, and food security.

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References
WMO (2026) State of the Climate in Asia 2025. WMO-No. 1397. https://doi.org/10.59327/WMO/S/CRI/SOC/3/ASIA
WMO (2022) State of Global Water Resources 2021. WMO-No. 1308. https://library.wmo.int/idurl/4/58262

Contributor: Miyuki IIYAMA, Strategic Coordination Office