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.