Environmental Impact: Deforestation, Pollution, and Conservation

Deforestation

The technique used to clear forests today is often called slash and burn. It is the rapid destruction of woodland, leading to:

• Reduced soil fertility
• Flooding and landslips
• Disrupted nutrient recycling
• Climatic changes
• Species extinction

The Causes of Oxygen Depletion

Most aquatic organisms respire aerobically and require oxygen from their environment. The two pollutants that most often reduce oxygen in water are:

• Fertilisers: Nitrates and phosphates added to soil by farmers.
• Sewage: Contains an excellent source of organic food for bacteria and phosphates from detergents.

Eutrophication

If a pond or river receives too many nutrients, it is called eutrophication. The solution to this problem is straightforward: do not allow excess nutrients into the water.

Causes

• Leaching of fertilisers
• Input of raw sewage
• Liquid manure

Effects

Depleted oxygen levels in water cause the death of fish and most invertebrates.

Solutions

• Treat sewage before it enters rivers
• Prevent farmyard drainage from entering rivers and ponds
• Control the use of fertilisers
• Bubble a stream of air through badly polluted ponds

Pollution

Pollution is any effect of human activities upon the environment, and a pollutant is any product of human activities that has a harmful effect on the environment. Two major problems with the Earth's atmosphere are the greenhouse effect and the production of acid rain.

Causes of the Greenhouse Effect

• Trapping infrared radiation close to the Earth's surface
• Carbon dioxide released by combustion
• Methane produced in animal guts
• CFCs from aerosols

Effects

• Global warming
• Greater climatic extremes
• Melting of polar ice and changes in sea water density
• Increased evaporation of water
• Pests spreading to new areas

Solutions

• Reduce the burning of fossil fuels
• Reduce the cutting of forests

Reforestation and Afforestation

• Reforestation: Planting trees in areas that have been cleared.
• Afforestation: Planting trees in new sites.

Reasons for Planting Trees

• Providing timber for building
• Reversing soil erosion
• Providing valuable wildlife habitats
• Creating recreational areas

Endangered Species

Primary threats include pest control, commercial exploitation, and loss of habitats.

Conservation Strategies

• Preservation
• Reclamation
• Creation

Management of Solid Waste

Two alternative ways of disposing of refuse are incineration and landfill.

Recycling

Recycling involves reusing waste products or materials which would otherwise be thrown away.