(a)What are environmental hazards? (b)List three examples of environmental hazards. (c)Explain five ways of preventing desert encroachment.

Answer Details

(a) Meaning of environmental hazards

Environmental hazards are natural or human-induced events, processes or conditions in the environment that pose a threat to human life, property, economic activities and the natural landscape. They are potentially damaging occurrences within the biophysical environment that can result in loss of life, injury, destruction of property or disruption of social and economic life.

(b) Three examples of environmental hazards

1. Flooding.
2. Drought and desertification.
3. Earthquakes (or volcanic eruptions, landslides, soil erosion, deforestation and pollution).

(c) Five ways of preventing desert encroachment

1. Afforestation and reforestation: Planting trees and grasses over bare land binds the soil with roots, reduces wind speed at ground level and returns moisture to the atmosphere, so the desert margin is held back.
2. Establishment of shelter belts (windbreaks): Rows of drought-resistant trees planted at right angles to the prevailing wind reduce wind erosion and prevent sand from being blown onto farmland and settlements.
3. Control of overgrazing: Limiting the number of animals per unit of land and practising rotational grazing allows vegetation to recover, keeping the ground covered so that wind and sun cannot strip and dry the soil.
4. Control of bush burning and deforestation: Enforcing laws against indiscriminate burning and tree felling preserves the protective vegetation cover that shields the soil from drying and erosion.
5. Provision of irrigation and water conservation: Building dams, boreholes and irrigation channels supplies water to dry areas, enabling continuous cultivation and vegetation growth that hold the land against advancing sand.

Public enlightenment on land conservation and the use of alternative fuels (to reduce dependence on firewood) also help to check desert encroachment.