Over half of the world’s population lives in watersheds of major rivers originating in mountains with glaciers and snow. A warming climate is now causing a global recession in glaciers, and some areas may lose their glaciers entirely in this century.
For millennia, these rivers have formed life lines of cultures, food production, livelihoods and biodiversity. In modern times, these rivers also provide cooling water for power sta- tions and water supplies for industry.
This report calls for accelerating research, monitoring and modeling of glaciers, snow and their role in water supplies. But perhaps even more important, this report highlights the vulnerability and exposure of people dependent upon these rivers to floods, droughts and eventually shortages as a result of changes in the melting and freezing cycles linked with cli- mate change and other pollution impacts.
The impact of floods was brought into sharp relief in Paki- stan in August 2010. As of November 2010, over six million people were still being affected by this disaster, with many displaced and housing, livelihoods, crops and livestock lost.
Worldwide, and particularly in Asia, over a hundred million people are strongly affected by floods every year, killing tens of thousands and increasing cases of disease and ill health as cities with limited or no sewage capacity become flooded and polluted water infiltrates drinking water sources and houses.
Here lies a crucial message for all nations involved. Changes in the intensity and timing of rains, added to variable snow and glacier melt will increasingly challenge food security and the livelihoods of the most vulnerable under various climate change scenarios.
With urban populations expected to nearly double to over six billion people in 40 years, and land pressures rising in the surrounding hills, the development of strategies for adapta- tion is urgently needed with women often being in the center of the ability of families to cope.
Adaptation strategies need to be wide ranging covering issues such as urban planning, improved water storage networks and improved water efficiency in sectors such as agriculture, but also the rehabilitation and restoration of critical ecosystems ranging from forests to wetlands which can enhance water supplies and act as buffers against extreme climatic events such as flooding.
Glaciers and trends in their mass and size have recently been at the centre of the climate change debate. This report confirms the work of bodies such as the World Glacial Monitoring Servic- es: namely that the overall trend is one of loss and shrinkage and that improved monitoring in many developing country regions will improve global scientific understanding while contributing to better early warning of potentially hazardous events.
I would like to thank the authors and contributors drawn from research centres in Asia, Europe, Latin America and North America for their efforts in making this report rigorous, im- partial and above all contribution towards advancing human- ity’s options and actions in a climate constrained world.
Achim Steiner UN Under-Secretary General and UNEP Executive Director