2. GLOBAL WARMING
a gradual increase in the
overall temperature of the
earth's atmosphere generally
attributed to the greenhouse
effect caused by increased
levels of carbon dioxide,
chlorofluorocarbons, and other
pollutants.
4. CARBON DIOXIDE
It accounts for 50% of the green house
effect, has increased by 25% .
Carbon is emitted mainly by cars,
factories and wherever fossil fuel is
used
Deforestation, which is a current global
environmental problem, removes trees
that would otherwise absorb the
carbon dioxide, thus increasing its
release into the atmosphere.
5. METHANE
Responsible for 15%-20% of the green
house effect, has more than doubled
in the last two centuries due to the
burning of wood, increasing areas of
rice cultivation, garbage, landfills,
livestock, manure, termite mounds,
leakage from natural gas exploration
and coal mining.
6. CHLOROFLUOROCAR
BONS
(CFC’s) account for 15%-25% opf the
green house gases and are released
from refrigerators, air conditioning
units, aerosol sprays, solvents in
electronic products, manufacture of
foam insulation material, electrical
circuit board cleaners, and styrofoam
packaging (Buchholz 1998).
7. A more powerful catalyst than
carbon dioxide, a single (CFC)
molecule traps 15,000 times more
heat than a CO2 molecule.
Although carbon dioxide is more
plentiful, it only stays in the
atmosphere for decades while a
chlorine molecule remains from 75
to 100 years.
8. NITROUS OXIDE
The laughing gas formed
from the breakdown of
chemical fertilizers and
burning of coal, and
industrial processes,
accounts for 5% .
11. EFFECTS OF GLOBAL
WARMING
are the environmental and social changes
caused (directly or indirectly) by human
emissions of greenhouse gases. There is a
scientific consensus that climate change is
occurring, and that human activities are the
primary driver.Many impacts of climate
change have already been observed,
including glacier retreat,changes in the timing
of seasonal events (e.g., earlier flowering of
plants),and changes in agricultural
productivity.
12. 1. Increased probability and
intensity of droughts and
heat waves
As the atmosphere gets saturated with higher
levels of green house gases, surface temperatures
on the Earth are bound to increase. These gases
tend to absorb and retain more of sun’s heat
without allowing it to escape freely into the outer
space, causing the land, air and water to heat up.
This in turn speeds up evaporation of water from
the land and fresh water sources, leading to
frequent and severe drought conditions. High land
and air temperatures create intense heat
conditions.
13. 2. Polar ice caps melting
Ice caps and glaciers that dominate the Arctic Pole
have started to melt at an alarming rate, submerging
vast expanse of land in the process. The melt down is
also simultaneously opening up access to vast deep
sea oil and gas deposits, including methane in the
Tundra region, endangering the Arctic marine
ecosystem, impacting shipping routes, and the cool
water currents that flow down to Europe and Africa.
A tremendous change is also observed in terms of the
new land revealed by melting ice, and variations in
shore-lines, leading to conflicting international
interests in the geographical terrain.
14. 3. More floods
• Heat wave conditions and increasing land
and air temperature trigger faster
evaporation of water, eventually leading to
cloud formation and torrential downpours.
Varying temperature settings are bound to
create flash floods other than those
occurring during the regular rainy seasons.
Research findings reveal that a two-degree
increase in global temperatures will
increase frequency of floods occurring in a
century, by up to 5 times.
15. 4. Fires and wildfires
• De-forestation associated with farming and
construction of residential buildings bordering
forest land, sparse dry vegetation, combined
with drought and high temperatures, form an
ideal setting for wildfires which rage over
forests and bush lands for days together.
Instances of wildfires are expected to be on the
rise with the increase in heat wave conditions,
which are commonly associated with the
greenhouse effect. In the absence of green
cover, lightning induced fires are also expected
to be on the rise resulting in loss of
human/wild life and property.
16. 5. Increased volcanic activity
• Although there is no immediate danger of
volcanic disaster, a research carried out by a
team from University of Leeds, headed by Dr
Carolina Pagli, reveals that melting glaciers
in Iceland and other polar regions have
reduced the mass of the Arctic ice-cap, and
hence the pressure exerted by the ice on the
land beneath it. Absence of sufficient
pressure, allows the rock deep within the
Earth’s surface, to melt easily and the extra
magma be thrown up through the active
volcanoes.
17. El Niño
is the warm phase of the El Niño
Southern Oscillation (commonly called
ENSO) and is associated with a band of
warm ocean water that develops in the
central and east-central equatorial
Pacific (between approximately the
International Date Line and 120°W),
including off the Pacific coast of South
America.
18. CAUSE OF El Niño
happens when weakening trade winds
(which sometimes even reverse
direction) allow the warmer water from
the western Pacific to flow toward the
east. This flattens out the sea level,
builds up warm surface water off the
coast of South America, and increases
the temperature of the water in the
eastern Pacific.
19.
20. LA Ni·ña
• a cooling of the water in the
equatorial Pacific that occurs at
irregular intervals and is
associated with widespread
changes in weather patterns
complementary to those of El Niño,
but less extensive and damaging in
their effects.
21. CAUSE OF LA
Ni·ñacaused by a build-up of cooler-than-
normal waters in the tropical Pacific,
the area of the Pacific Ocean between
the Tropic of Cancer and the Tropic of
Capricorn. Unusually strong, eastward-
moving trade winds and ocean currents
bring this cold water to the surface, a
process known as upwelling.
