Hydrology and Climate Change

A Brief Definition:

Climate Change is the pattern of changes weather affecting global or regional climate as measured such as average temperature, rainfall and evaporation etc. It is known as the alteration in frequency of extreme weather conditions. This variation in weather pattern and duration may be caused by human activities and natural processes. Global warming is the main cause of climate change.

These days climate change is the burning issue in all part of the world, because it is one of the prominent factors for destruction in the earth’s environment and is more vital to the human life; Farmers are facing the most difficult condition in their occupation. It is unnatural such that there are flooding problems due to heavy rainfall during monsoon season and drought problems during dry season.

The earth’s atmosphere is composed of different types of greenhouse gases such as carbon dioxide (CO2) , water vapour (H2O), methane (CH4), nitrous oxide (NO2), and ozone (O3), etc these gases trap the sun's heat and keep the earth warm. They create a warm blanket around the earth which is known as green house effect. If the concentration of greenhouse gases increases in the atmosphere, it will trap more heat and the earth will get warmer and warmer is known as global warming. The average temperature is increasing each year since 1960 and we are noticing its differences effectively since 1980. The rate of increment of average temperature from analysis of recorded data is about 0.06 degree centigrate per year (DHM, Kathmandu).

It has been estimated that the causes of the global warming are due to the increase in the human made chemicals like chlorofluorocarbons, Hydro-fluorocarbons as well as in the increase of gases like carbon dioxide, sulphur dioxide, sulphur oxide, methane and ozone. The most effective for global warming is increasing of water vapors in atmosphere. These gases acts like a barrier which do not allow the heat to radiate from earth to the space but reflects it back to the earth atmosphere.

All life on the earth is dependent, one way or another, on water. The study of science of water is therefore, important. Specially, hydrology can be defined as a science that deals with space-time characteristics of the quantity and quality of the water on the earth, encompassing their occurrence, movement, distribution, circulation, storage, exploration, development, and management. These characteristics are determined by the relation of water on earth. The definition of hydrology is not unique. In a general sense, hydrology is a very broad subject including some multitude of disciplines involving agriculture, biology, chemistry, geology, glaciology, meteorology, oceanography, geography, physics, volcano-logy, and many other disciplines. The involvement of hydrology with this science comes about by the reason of the close association of water with the atmosphere and the earth. Hydrology is partitioned into

(1) Surface-water hydrology,
(2) Ground water hydrology.

Surface water hydrology is defined to the relation between the water and the surface of the earth, whereas Ground water hydrology deals with the relation between water and the lithosphere or the subsurface portion of the earth. It deals with surface water hydrology, with importance on the drainage basin as the origin of the surface water.