Mountains and highlands are found in every continent; they cover about a quarter of the Earth’s land surface and are home to 10% of the world’s people. Another 40% live in adjacent lower watershed areas; thus more than half the global population is directly or indirectly dependent on mountain resources, the foremost being water for drinking and home use, irrigation, hydro power, industry and transportation. The crops that feed the cities are raised in the valleys and flat river plains, but the fate of the valleys is decided in the hills and mountains where the streams rise. Where the hill slopes and ridges in the upper reaches are covered with trees, the streams flow clearly and steadily and all is well in the valleys below.
Where the trees are gone, the soil washes down the slopes to clog the streams and foul the river bottoms thus raising the water level. When it rains in the hills there is no soil left to hold the water resulting in flash floods which in turn sweep down into the valleys resulting in rivers bursting their banks ruining crops and lives, and wash yet more soil away to the sea. The water is wasted and the deserts spread. The degradation of mountain ecosystems – home and livelihood to millions – threatens to seriously worsen global environmental problems including floods, landslides and famine. While several of the world’s mountain areas are in relatively good ecological shape, many face accelerating environmental and cultural decline brought on in part by government and multilateral agency policies too often founded on inadequate research.
People living in the mountain areas worldwide, who are among the poorest of the poor, are extremely rich in environmental understanding. Their opinions and experiences need to be combined with scientific knowledge, together with cultural diversity-a prevailing feature of mountain life, must be considered as complementary to biodiversity if sustainable mountain development is to be achieved. The widespread conflict in mountain regions, including conventional warfare, terrorism, guerrilla insurgency and repression of minority peoples, must be tackled far more vigorously than hitherto.
The management and utilization of the natural resources of mountains, especially water, must be undertaken in such way that mountain people share the benefits. Despite the importance of reliable data, hydro-meteorological networks in many countries have declined seriously in the last decades. The development of strategies, techniques and methodologies to acquire these data at local, regional and global scales and the establishment of mechanisms for making these data freely available are vital. Information technology enhances the link between mathematical models and data. In this respect remote sensing based information requires analysis and its translation into hydrological characteristics needs to be carried out.