Changing Waters in the Hindu Kush Himalayas: Mapping resources for new challenges

By: Arun Bhakta Shrestha, ICIMOD , Nand Kishor Agrawal, ICIMOD Björn Alfthan, GRID-Arendal Sagar Ratna Bajracharya, ICIMOD , Judith Maréchal, ICIMOD , Bob van Oort, CICERO

New Delhi, February 11 (G’nY News Service): The Hindu Kush Himalayas (HKH) are the freshwater towers of South Asia and parts of Southeast Asia. Water originating from their snow, glaciers and rainfall feed the ten largest river systems in Asia, supporting the drinking water, irrigation, energy, industry and sanitation needs of 1.5 billion people living in the mountains and downstream. The HKH region spreads over 8 countries, from Afghanistan in the West to Myanmar in the East, and North-South from China to India, including Bangladesh, Bhutan, Nepal and Pakistan.

Global water resources today face increasing pressure from climate change and rising consumption. Yet knowledge about the changing climate in the mountains and its possible impacts is still lacking. What is certain is that adaptation to climate change needs to begin now, as recently stressed during the COP21 negotiations, and even more so in the world’s mountain regions, which, according to the IPCC, are among the most vulnerable to climate change.

This challenge has led three organisations – the International Centre for Integrated Mountain Development (ICIMOD), GRID-Arendal and the Centre for International Climate and Environmental Research-Oslo (CICERO), to come together and create the Himalayan Climate Change Adaptation Programme (HICAP). Its objective is to increase the resilience of mountain communities, by generating knowledge on the impact of climate change on natural resources, ecosystem services, and the communities depending on them.

After several years of research, HICAP has now published its findings in a regional water atlas that can act as a guidebook for policy makers tackling crucial adaptation issues. The Himalayan Climate and Water Atlas: Impact of Climate Change on Water Resources in Five of Asia’s Major River Basins, was recently launched in Paris at COP21. The first of its kind, the atlas offers a comprehensive, regional understanding of the changing climate and its impact on water resources in five major river basins in the region – the Indus, Brahmaputra, Ganges, Salween and Mekong. It sheds light on the state and fate of the water resources of the HKH, and presents science-based information that will help develop solutions and initiate necessary action to deal with changes in the region.

HICAP Findings and recommendations

As per its findings, studies under HICAP reveal that temperatures across the mountainous HKHwill increase by about 1–2°C , with the rise as high as 4–5°C in some places by 2050; precipitations will change by an average of 5 per cent, and a maximum of 25 per cent by 2050, with monsoons becoming longer and more erratic; and extreme rainfall events getting less frequent, but more violent and likely to increase in intensity. Glaciers will continue to suffer substantial ice loss, with the main loss in the Indus basin. Consequently, the relative contribution of different sources of water – glacial melt, snow melt, rainfall, and base flow – to river flow will change, with consequences for water management practices.

Despite overall greater projected river flow, higher variability in river flows and more water in pre-monsoon months are expected, leading to higher incidence of unexpected floods and droughts. As a result, the livelihood security and agriculture of river-dependent people will be greatly impacted, with communities living immediately downstream beneath glaciers becoming the most vulnerable to glacial changes.

Recommendations resulting from the study notably include the need to implement flexible and diverse solutions to address the high level of uncertainty, and adequately prepare for extreme events. The HICAP atlas calls for urgent restructuring of farming systems towards higher flexibility so that they can withstand the increased risk of floods, and lower water availability Both structural (such as flood prevention structures) and non-structural measures (such as the implementation and enforcement of building codes, land use planning laws or early-warning systems) to reduce exposure, vulnerability and risks for populations, are called for.

Recommendations also suggest strengthening the modeling approaches by increasing spatial resolution as well as incorporating more mountain-specific physical processes, in order to reduce uncertainty. More research to fill critical gaps and better understand factors impacting the springs, which are the major source of water in the mid-hills, in order to take the right measures to improve their functioning is suggested.

It also calls for improved regional coordination and sharing of, data combining of in situ and remote sensing measurements, and innovative modeling approaches. The development of a river basin approach is also recommended to protect Himalayan ecosystems and harness the potential of water resources.

Story by:
Arun Bhakta Shrestha, ICIMOD
Björn Alfthan, GRID-Arendal
Sagar Ratna Bajracharya, ICIMOD
Judith Maréchal, ICIMOD
Bob van Oort, CICERO

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