The
first photographs from space
brought home the fact that earth
is an integrated and isolated system concern
that human impacts could be changing the equilibrium of this system grew
in the 1970’s as theories about ozone depletion and the green house effect developed.
The concept of the earth changing over various
of the earth changing over
various this seals was not new, solar and
astronomical cycles, the waxing
and wanning of Ice
ages, and seasonal changes have long been recognized what was new the realization
that humans can have a lasting
and far reaching impact on earths
natural fluctuation and
cycle.
Potential human impacts on
climate are linked to the
globally increasing emission of green houses gases through activities
such as burning fossil fuels
(coal, oil, natural gas) deforestation fertilizing crop lands and hearting air conditioning and lighting building s. green house gases like other atmospheric gases allow sunlight to reach
and warm the earth surface,
unlike other atmosphere gases, however, they
trap much of the heat and keep
it from
escaping back into space
such the surface of the earth source of
them the chlorofluorocarbon (CFC)
and halons also react with
sunlight in the upper atmosphere
to destroy the ozone
layer around the earth.
In industrialized counties green house
goes emissions are primarily
related to energy use, with only
20 percent of the worlds
population these countries account
for 75 percent of annual energy use, in developing countries current
green house gas emission are tied
primarily to change in land
use practices e.g
deforestation .
We cannot predict the magnitude of climatic
effects from green house gas
emission with accuracy. But it is clear that the decision to limit emission cannot await
the time when the full impacts
are evident . the leg time between emission
of the gas and their full impact is on the order of decades to centuries, so
too is the time needed to reverse any effects. Today’s emission thus commit the plant to changes
well into the 21st century. And the
leg times between identification of policy options legislation
of controls and actual implementation
of the
act of the will begin now and continues
over the next 10 to 20 years
Among individual countries the united states is the leading
with 5 percent of the worlds
population, the united states accounts for
about 20 percent of the worlds warming commitment.
US co2 emission
20 percent of the global total
originate almost exclusively from
fossil fuel combustion.
Anthropogenic sources of maintain in the united states account for
about 6 percent of global emission from all sources land
fills, coalmining and domestic animals
account for most of us total (2,24)
the united states also consumes between 20 30
percent of the worlds (EFU and CFC -12
the two noise damaging chlorpluor carbons in learns of
global warming.
Roughly
60-70 percent of theses passes are scheduled to be phased out by the
year 2000 under the revised Montreal protocol US nitrous
oxide emission roughly 15-20
percent of the manmade global
total refers 6-24 originated
primarily from fertilizer break
down and high temperature fossil fuel
emission . green house gas
emissions are closely entwined in the limited states with energy use currently, America uses about 15 times more energy
per person than does the typical
developing country.
The warming commitment or irradiative
forcing caused by the different green hues
is not
equal. It depends on the absorbing characteristic concentration in the atmosphere and the life time of each gas .
Although the other gases are more potent
on a per include basis, currently Co2 accounts for an estimated 55 percent of the committed to global warming . this is largely
due to fact that so much CO2 has been emitted world wide (6 billion metric tons of carbon is
1988) as to snap the higher
radiates facings per unit of the other
gases (24) percent of the current CH4
is responsible for 15, percent
and N20 for 6 percent
Recently, public interest and concern over
global changes intensified with
the discovery of annual ozone hole
over Antarctica, thinning ozone
over arctic, the severe drought
of 1988 and recent abnormal
wealth patters in Europe international concern was
demonstrated by the recent
rapid renegotiation of the Montreal protocol to comradely
phase (CFC) and assist
developing countries in achieving that
goal many in industrialized countries
principally in Europe have further
called for a 20 percent reduction in
CO2 emission from the developed world by 2015
or shortly thereafter, several
have pleaded to freezers reduce
emission whether or not the rest of the participated
In conclusion, the major options available or likely to be available
for reducing CO2 emission in
the near term fall into three categories
1.
Increasing
energy conversion and efficiency in end
use technologies
2.
Changing
use patterns to conserve energy
3.
Shifting
energy
Shifting energy
supply award form high CO2 emitting fuels