This document discusses global warming and its causes. The main points are: 1) The troposphere traps heat from certain gases, causing the greenhouse effect. The major greenhouse gases are carbon dioxide, methane, nitrous oxide, chlorofluorocarbons, and water vapor. 2) Human activities like burning fossil fuels and deforestation have increased the concentration of greenhouse gases in the atmosphere, enhancing the greenhouse effect and raising global temperatures. 3) Carbon dioxide contributes most to increased warming, and industrial countries produce the majority of carbon dioxide emissions from fossil fuel combustion and deforestation.

1. By
Dr.A.Lovelin Jerald
Associate Professor
Department of Food Processing and Preservation Technology
Faculty of Engineering
Avinashilingam Institute for Home Science and Higher Education for Women,
Coimbatore

2. GLOBAL WARMING
Troposphere the lowermost layer of the atmosphere ,
traps heat by a natural process due to the presence of
certain gases.
This effect is called greenhouse effect .
The amount of heat trapped in the atmosphere
depends mostly on the concentration of “heat trapping
or greenhouse “ gases.

3. MAJOR GREEN HOUSE GASES
Carbon dioxide
Methane
Nitrous oxide
Chlorofluorocarbon
Water vapour

4.  The average global temperature is 15 c
 In the absence of greenhouse gasses this temperature
would have been -18 c
 Greenhouse effect contributes a temperature rise to
the 33 c
 The two predominant greenhouse gases are water
vapours which are control by hydrological cycle

5. Greenhouse gases
 The phenomenon that worries the environmental
scientist is that due to anthropogenic activites there is
an increase the concentration of the greenhouse gases
in the air that absorb infra-red light containing heat &
result in the radiation of even more of the outgoing
thermal infrared energy there by increasing the
average surface temperature 15 c

6. CARBON DIOXIDE
 It contributes about 55% to global warming from
greenhouse gases produced by human activity
 Industrial countries account for about 76% of annual
emissions
 The main source of fossil fuel burning & deforestation

7. Chlorofluorocarbon
 These are believed to be responsible for 24 % of the
human contribution to greenhouse gases
 The main source of CFCs include leaking air
conditioners & refrigerators evaporation of industrial
solvent production of plastic foams aerosols,
propellants

8. METHANE
 It account for 18 %of the increased greenhouse gases
 Methane is produced when bacteria break down dead
organic matter in the moist places that lack oxygen
such as swamps , natural wet land , paddy field ,
landfills.
 Atmospheric concentration of methane is 1.675ppm
&it is increase at a rate of 1 %annually .

9. NITROUS OXIDE
 It is responsible for 6 % of the human input of
greenhouse effect .
 Besides trapping heat in the troposphere it deplets
ozone in stratosphere .
 It is released from nylon products ,from burning of
biomass & nitrogen fertilizers .
 The atmospheric concentration of nitrous oxide is 0.3
ppm

10. IMPACTS OF ENHANCED
GREENHOUSE EFFECT
 Global temperature increase
 Rise in sea level
 Effects of human health
 Effects of agriculture

11. MEASURES TO CHECK GLOBAL
WARMING
use energy more efficiently
 Shift to renewable energy resources
 Plant more trees
 Shift from coal to natural gas
 Stabilize population growth

12. Effects of acid rain
 it damage metals & car finishes
 It damage foliage & weaken trees
 Aquatic life especially fish are badly affected by
acidification

13. CONTROL OF ACID RAIN
Emission of so2 & no2 from industries & power plant
should be reduced by using pollution control
equipment
Liming of lakes & soil should be done to correct the
adverse effects of acid rain .
A coating of protective layer of inert polymer should
be given in the interior of water pipes for drinking
water.

14. Thank You