Copenhagen, Dec 14 :Around 1.3 billion people in India, the rest of South Asia and China are at imminent risk of water shortage due to climate change, according to the UN.

The Kathmandu-based UN organisation International Centre for Integrated Mountain Development (ICIMOD) has found that "global warming is having a serious impact on the amount of snow and ice" in the Himalayas, "which has serious implications for downstream water availability as up to 50 percent of the average annual flows in the rivers are contributed by snow and glacial melting".

ICIMOD Monday presented its latest report, "The changing Himalayas", on the sidelines of the Dec 7-18 climate summit here. Mats Eriksson, co-author of the report, pointed out: "The warming in the greater Himalayas has been much more than the global average - for example, 0.6 degrees Celsius per decade in Nepal, compared to the global average of 0.74 degrees over the last 100 years".

Eriksson said the effect of climate change on rainfall and snowfall patterns has been "more ambiguous, with both increasing and decreasing trends in different parts of the region".

He warned: "The most serious changes are probably related to the frequency and magnitude of extreme weather events, such as intense rainfall leading to flash floods, landslides and the flow of debris."

All the major rivers of South Asia and China flow from the Himalayas, with 1.3 billion people living in these river basins.

Eriksson said there was still critical lack of data on many aspects of the Himalayan ecosystem, because "climate change-induced hazards such as floods, landslides and droughts will impose significant stresses on the livelihoods of mountain people and downstream populations".

He talked of the need not only for more climate science, but more social science. "Society will need to improve its adaptation strategies, and level structural inequalities that make adaptation by poor people more difficult.

"It is important to strengthen local knowledge, innovations and practices within social and ecological systems as well as strengthening the functioning of institutions relevant for adaptation."

In a similar report released here last weekend, ICIMOD had said the biggest problem in the Himalayas now was that there was "either too much water, or too little".

The report pointed out that in Bihar, embankments built to contain the Kosi River have led to waterlogging, and even worse, cause catastrophic floods when they suddenly burst as a result of improper construction and inadequate maintenance. People who have settled closest to the embankments are the most vulnerable and take the heaviest toll.

"Policies that determine people's access to resources when facing water stress and floods are currently weak throughout the region, thus people rely on their own innovations," said ICIMOD director general Andreas Schild. "Governments have to find ways to support improved livelihood strategies, and increase people's influence in the governance of infrastructure, such as embankments," he added.(IANS)