Question

(i) Why and how must the ozone layer in the stratosphere be protected? Explain.

(ii) How do deforestation and greenhouse gases negatively affect our environment? Explain.

Answer 1

The ozone layer present in the stratosphere must be protected in many ways for our survival:

Ozone acts as a shield and absorbs ultraviolet radiations from the sun. UV rays are extremely harmful to living organisms.

Ozone gas is continuously formed by the action of UV rays on molecular oxygen and also degraded into molecular oxygen in the stratosphere. In order to protect the ozone layer, there should be a balance between production and degradation of ozone in the stratosphere. In recent past, the balance has been disrupted due to enhancement of ozone degradation by chlorofluorocarbon (CFCs). So in this way the emission of ozone degrading substances like CFCs need to be controlled to protect the ozone layer in the stratosphere.    

Effects of Deforestation : It is the conversion of forested areas to non-forested areas. Its effects are : 

• It increases the level of CO₂ concentration in the atmosphere.
• It results into the loss of biodiversity due to habitat destruction.
• It disturbs, the hydrdogical cycle.
• It leads to soil erosion.
• In extreme cases it also causes destrification. 

Effects of Greenhouse Gases :

• The main greenhouse gases are CO₂, Methane - (CH₄) and CFCs. Their high level in the atmosphere allow the heat waves to reach earth, but prevent their escape and earth becomes warm. This increased temperature in last three decades has caused changes in precipitation patterns.
• The increased temperature also causes Eh-nino effect melting of the polar ice caps and Himalayan snow.