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
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