Global Issues: Ozone Depletion, Global Warming and Acid Rain

  Global Issues.ppt (Size: 4.09 MB / Downloads: 18)
Introduction

Air pollution is exerting increasing impact on the environment. Humans have been altering the chemistry of the atmosphere on a global scale. These changes may:
Modify the global climate
Threaten the health of human beings
Create many environmental problems such as
Acid rain
Depletion of ozone layer
Global warming
Seriously upset the global ecosystem

What is ozone depletion?

Ozone is a highly reactive gas comprising triatomic oxygen
Ozone layer in the stratosphere protects the Earth’s surface from UV light
Ozone depletion refers to a lowered concentration of ozone in the upper atmosphere
“Holes” are formed
More UV radiation is reaching the Earth’s surface .

What are the effects of ozone depletion?

UV radiation is absorbed by DNA and modifies them, affecting the expression of genetic information
A higher incidence of skin cancer,lung diseases and cataract
Reduce the yields of crops
Disruption of the ecological balance in the ocean
A higher incidence of photochemical smog

What is global warming?

Global warming refers to the gradual increase in the average temperature in the atmosphere
Increase in concentration of greenhouse gases in the atmosphere
The heat loss from the Earth to the Space is slowed down
An enhancement of the greenhouse effect leads to global warming
Greenhouse gases include carbon dioxide, chlorofluorocarbons, methane, nitrous oxides, ozone, water vapour, etc