Human Induced Climate Change

The unprecedented changes observed in natural environment during 20th century is the outcome of rapid industrialization and population growth occurred worldwide (Beniston, 2003).The over exploitation of natural resources (e.g. forest, water and land etc.) in recent past, attributed to environmental degradation, which in long-term disturbed global climate system and resulted into climate change. Climate change refers to any change in climate over time, whether due to natural variability or as a result of human activity (IPCC, 2007). This describes changes in the variability or mean state of the atmosphere over time scales ranging from decades to millions of years. The threat of human induced climate change presents a difficult challenge to

Approximately, 17% area of the IHR is under permanent snow cover and glaciers, and about 30-40% under seasonal snow cover. The IHR serves as water reservoirs for the country by feeding the rivers, originating from the Himalaya. Himachal Pradesh with highly variable topography having elevation range of 350 to 7000 m is divided into five distinct physiographic units from south to north: (1) Alluvial Plains (the southernmost zone developed at the foothills of Siwalik Range), (2) Sub-Himalayan zone, (3) Lesser Himalayan zone, (4) Central/Great Himalayan zone, and (5) Trans-Himalayan zone. The significant variations in the altitudes and aspects have resulted in variety of climate causing different types of flora and fauna in the state. The climate varies from hot and moist tropical climate in lower valleys to cool temperate climate at about 2000 m, and tends towards polar as the altitude increases beyond 2000 m. Therefore, decline in the patterns of precipitation and temperature is noticed from west to the east, and south to the north. The average rainfall in Himachal Pradesh is 1,111 mm, varying from 450 mm in Lahaul and Spiti to over 3,400 mm in Dharamsala. Winter precipitation occurs as snow at elevations above 1800 m. The natural vegetation types in this region vary from Sub-tropical moist pine forest to Alpine forest. The Sub-tropical moist pine forests are found in the lower regions at altitudes varying from 1000m to 2000m where the mean rainfall (750mm-1250mm) and temperature (18°C-21°C) are very high. The upper regions (>3000m) are characterized by very dry climate and temperature often goes below zero in winter. The vegetation is sparse, discontinuous and scattered represented by Alpine shrubs and grasses. In between these two extreme, Himalayan moist temperate forests