Environmental Quality & Sustainability

Greenhouse Effect

Tasks

1. Using page 52, define the greenhouse effect
2. Get a copy of figure 1.2
3. Why is the greenhouse effect an important natural process?
4. Define the enhanced greenhouse effect.
5. Describe ways in which humans are contributing to this.
6. Why is the enhanced greenhouse effect causing so much alarm around the world?
7. Describe natural factors affect global climate change:
8. solar variations
9. MIilankovitch cycles
10. Volcanic eruptions

Soil Degradation

Objective:Understand the processes that are leading to soil degradation and be able to describe the impacts that this is having on the environment and human populations.

Definition: A severe reduction in the quality of soils. The term includes soil erosion, salinization and soil exhaustion (loss of fertility)

"It takes such a long time for soil to form – some 10-12,000 years to build up to depths we might describe as productive land. First, the rocks that have made it from the Earth's interior to the surface must be "weathered" by wind and rain, a disintegration that is assisted by microorganisms, insects and lichen. This organic matter decays, feeding more organisms, including, in time, plants. It is the accumulation of hundreds of years of this organic matter, living organisms and minerals that we call soil. It takes a few hundred years to produce each centimetre of soil (although it is a little faster in the tropics), but it can be lost in a matter of hours."

source: http://www.bbc.com/future/story/20120209-mud-mud-glorious-vanishing-mud

Causes & Implications of soil degradation

Read this Guardian article

1. How much arable land has been lost in the last 40 years?
2. What are the main causes of the loss of soil?
3. Explain why continuous ploughing leads to soil loss?
4. Explain why heavy use of fertilisers is leading declining soil quality?
5. Why is soil degradation such an important issue for the world?

Read this BBC article.

1. Explain why deforestation leads to soil erosion.
2. Why is urbanisation leading to a decline in the soils available for farming?
3. Soil degradation is likely to effect the poorest people in the world most. Explain this statement.

Solutions to Soil Degradation

Describe how the following methods can help reduce soil degradation

• Afforestation
• Contour ploughing
• No-till farming