In nature Greenhouse effect is extremely useful
as it is responsible for regulating Earth's
temperature and thereby help maintain earth's temperature at a level
which can sustain life.
This phenomena works similar to the glass in a
greenhouse which keeps heat in the greenhouse.
What happens inside the greenhouse?
Let us understand
how greenhouse effect works inside a real
greenhouse. Light enters through the glass and
is absorbed by the ground plants and pots inside
the greenhouse. They in turn, radiate heat,
infrared radiation, which is a non visible
light. Infrared rays with longer
wavelength than visible light cannot readily
escape through the glass panes; the rays are
trapped and the air inside the greenhouse warms
up. The same effect can be seen in a car on a
bright sunny day.
How greenhouse effect works in the atmosphere?
Our atmosphere
also traps the sun’s heat near earth’s surface,
primarily through heat-trapping properties of
certain “greenhouse gases” such as carbon
dioxide. In the atmosphere, Co2 molecules act
similarly to greenhouse's glass.
Earth is heated by sunlight. Most of the sun's energy
passes through the atmosphere, to
warm the earth's surface, oceans and atmosphere.
However, in order to keep the
atmosphere's energy in balance, the warmed earth also
emits heat energy back
to space as infrared radiation.
As this energy radiates upward, most is absorbed by
clouds and molecules of
greenhouse gases in the lower atmosphere. These
re-radiate the energy in all directions,
some back towards the surface and some upward, where
other molecules higher up can
absorb the energy again. This process of absorption and
re-emission is repeated until,
finally, the energy does escape from the atmosphere to
space.
However, because much of the energy has been recycled
downward, surface
temperatures become much warmer then if the greenhouse
gases were absent from the
atmosphere. This natural process is known as the
greenhouse effect.
Without greenhouse gases, Earth's average temperature
would be -18°C instead of
+14°C, or 33°C colder.
Over the past 10,000 years, the amount of greenhouse
gases in our atmosphere has
been relatively stable. Then a few centuries ago, their
concentrations began to increase
due to the increasing demand for energy caused by
industrialization and rising
populations, and due to changing land use and human
settlement patterns.
Watch movie depicting how greenhouse effect, global
warming and
climate change Happen
What
are Greenhouse gases?
Water vapors is the most common greenhouse gas. But
others that are very important too. Some
greenhouse gases such as CO2 or Carbon dioxide occur
naturally and are emitted to the atmosphere through
natural processes and human activities.
Carbon Dioxide or CO2 is the most significant
greenhouse gas released by human
activities, mostly through the burning of fossil fuels.
It is the main contributor to climate change. Carbon
dioxide enters the atmosphere through the burning of
fossil fuels such as oil, natural gas, and coal solid
waste, trees and wood products, and also as a result of
of manufacture of cement.
Roughly half of the CO2 emitted into the air
from burning fossil fuels dissolves in the
ocean. This process reduces the amount of
greenhouse gases in the atmosphere but it raises
the acidity of ocean water . This map shows the
total amount of human-made carbon dioxide in
ocean water from the surface to the sea floor.
Blue areas have low amounts, while yellow
regions are rich in anthropogenic carbon
dioxide. High amounts occur where currents carry
the carbon-dioxide-rich surface water into the
ocean depths. (Map adapted from Sabine et al.,
2004.)
Methane is produced when vegetation is burned,
digested or rotted with no oxygen present. Garbage
dumps, rice paddies, and grazing cows and other
livestock release lots
of methane
Nitrous oxide can be found naturally in the
environment but human activities are
increasing the amounts. Nitrous oxide is released when
chemical fertilizers and manure are used in agriculture.
Halocarbons are a family of chemicals that include CFCs
(which also damage the ozone layer), and other
human-made chemicals that contain chlorine and fluorine.
What
should we do to slow the process?
The greenhouse effect can be reversed by two ways (1)
Forestation (2) Reduction of greenhouse gases.
Forestation will help in more more absorption and
cleaning of Co2 by trees. (2) Reduce fossil fuel usage
and embrace new environmental friendly technologies such
as solar energy wind energy and battery operated
automobiles etc. Push our governments to sign and
implement
kyoto
protocol.
Effects of Climate
Change
What would
be the real impact of climate change remains uncertain, and
exact consequences of climate change to all living species
and environments across the world are also largely unknown.
However in order to learn about some estimated effects
Click here.
