Page 151 - Ai_417_V3.0_C9_Flipbook
P. 151
Main causes of global warming are:
• Excessive use of fossil fuels like coal, oil and natural gas produces greenhouse gases-like methane, nitrous oxide and
mainly carbon dioxide which trap the sun’s radiation within the atmosphere resulting in rise in global temperature.
This is called green house effect.
• Trees absorb CO from the atmosphere and release oxygen instead, so they work as air purifiers. Deforestation
2
due to urbanisation and industrialisation has reduced the number of trees on the earth. This has resulted in the
increase of carbon dioxide level in the atmosphere.
• Over-consumption of natural resources due to population explosion has also contributed to global warming.
• Increase in pollution is also responsible for the rise in global warming.
Greenhouse gases that occur both naturally and from human activities include water vapour, carbon dioxide (CO ),
2
methane (CH ), nitrous oxide (N O) and ozone (O ). Other greenhouse gases have essentially no natural sources, but are
3
4
2
the side products of industrial processes or manufactured for human purposes, such as cleaning agents, refrigerants,
and electrical insulators. These include the fluorinated gases: chlorofluorocarbons (CFCs), hydrochlorofluorocarbons
(HCFCs), hydrofluorocarbons (HFCs). This greenhouse effect causes snow to melt very fast. Carbon dioxide emissions
into the atmosphere from burning oil, coal and gas for energy use is a serious problem as it is harmful to the environment.
Carbon dioxide in the atmosphere has increased by 31% since pre-industrial times, causing more heat to be
trapped in the lower atmosphere. As a result, there are frequent floods and changes in climate as well as damage
to crops and animal life.
Harmful Radiation
You might be knowing that the atmosphere protects us from harmful radiation from the sun. This is done by a
layer all around the earth, in the atmosphere, called the "Ozone Layer". It is made of a gas called 'Ozone'. This layer
in the atmosphere protects us from the harmful radiation.
Cleaning chemicals, coolants in refrigerators and air conditioners, etc., release ozone depleting substances, such
as chlorofluorocarbons in the atmosphere. These destroy the ozone in the atmosphere, making holes in the ozone
layer. The harmful radiation comes in through these holes and causes increased incidence of health disorders, such
as skin cancer.
Natural Disasters
Natural disasters include floods, earthquakes, landslides, storms, etc. Our actions in exploiting natural resources
for building structures, such as large dams and buildings sometimes aggravates the impact of natural calamities
and disasters.
Mining Activity
Mining is the process of extracting useful minerals from the earth’s surface. It is estimated that two-thirds of the
world’s yearly mineral production is done by surface mining.
Green Skills-I 149

