Write explanatory notes on each of the following (a) deforestation (b) drought

(a) Deforestation

Deforestation is the large-scale clearing or removal of forests and trees from an area, usually without replanting, so that the land is put to other uses or left bare. It is caused by activities such as lumbering (logging), the clearing of land for farming and grazing, bush burning, fuel-wood collection, road building and the growth of settlements. Its effects are largely harmful: it exposes the soil to erosion and leaching, reduces soil fertility, lowers rainfall and destroys the water balance, causes loss of wildlife and biodiversity, and increases carbon dioxide in the air, contributing to global warming. It may also lead to desertification at forest margins. Deforestation can be controlled through afforestation and reforestation, control of bush burning, provision of alternative fuels and enforcement of forestry laws.

(b) Drought

Drought is a prolonged period of abnormally low or no rainfall, during which the water supply falls far below normal for a region, leading to acute shortage of water for plants, animals and people. It is caused by failure or lateness of the rains, persistent dry winds, deforestation and the general drying/advance of desert conditions. Its effects include crop failure and famine, death of livestock, drying up of rivers, streams and wells, migration of people and animals (environmental refugees), and the spread of desertification, as experienced in the Sahel region of West Africa. Its effects may be reduced by irrigation, water conservation and storage (dams), drought-resistant crops, afforestation and shelter belts, and early-warning and relief schemes.