The highlands: a shared water tower in a changing climate and changing Asia uri icon

abstract

  • The highlands of Asia have an average altitude of 4000 masl; and they extend from an altitude of 3000masl to include the whole of the Tibetan Plateau and most parts of the Pamir Plateau. The highlands contain the most extensive areas of glaciers and permafrost outside high latitudes. The region is often referred to as the â??Asian water towerâ??: the source of Asiaâ??s nine largest rivers the waters of which sustain over 1.3 billion people. The highlands of Asia have been ignored in comparison to other natural ecosystems, even though history has shown that, when ecological change takes place in the highlands, changes soon follow in the valleys and in the lowland plains. The impacts of climate change are superimposed on a variety of other environmental and social stresses in mountain ecosystems, and many of them have been recognized to be severe and cause uncertainty. Key impacts of climate change on the highlands include glacier retreat, shortage of fresh water, natural hazards, soil erosion, ecosystem degradation, and land desertification. The supply of fresh water, or the snow and ice meltwa- ter component, in large river basins is projected to increase over the following decades as perennial snow and ice decrease. Later, however, most scenarios suggest a decrease, even of catastrophic proportions, by the 2050s. The greatest challenge in the highlands of Asia is the very limited monitoring or understanding of the thresholds and cascades of climate change on the cryosphere, hydrosphere, biosphere, and on human society in the vertical dimension from highlands to uplands and from lowland plains to coastal areas. Impacts on water resources will differ depending upon the importance or influence of different sectors; and between forestry, agriculture, industry, ecosystems, or mitigation measures to reduce water-induced hazards. There are substantial variations within as well as between these sectors in different countries and valleys. Meanwhile, climate change is superimposed on a variety of other environmental and social stresses that cause uncertainty and lead to contradictory perceptions. Three practical suggestions are a) integrated research to understand highland complexities and reduce scientific uncertainty; b) promotion of regional cooperation and science-based dialogue to regulate blue, green, and virtual water flows; and c) building of social resilience and offsetting lack of knowledge of diverse human and ecological conditions by actively involving local communities; allowing their knowledge, innovations, practices, and con- cerns to inform understanding and help direct responses

publication date

  • 2008