THE CLIMATIC CHANGE IS GLOBAL
The Global Climatic Change is a variation in the average temperatures that is caused, either in a direct or in an indirect way by human activities that alter the global atmospheric composition, added to the natural climatic variability observed during comparable lapses of time.
The IPCC (International Panel Concerning Climatic Changes), a panel of 2500 first line scientists, reached the conclusion that "A discernible change due to human influence over the global climate can already be detected among many of the natural variables of the climate". According with this panel, the average temperature of the surface of the Earth has risen by approximately 0,6 °C during the last Century. The carbon dioxide emissions caused by the burning of fuel has reached 6.25 billion tonnes during 1996, setting a new record. On the other hand, 1996 was one of the five warmest years on record (since 1866). On other accounts, it is estimated that the loss damages related to climatic disasters reached US$ 60 billion in the same year, setting another record.
An hypothetic doubling-up of the hot house gases would increase the temperature of the Earth between 1 and 3.5 °C. Although it may not seem too much, it will mean a returning to the last glaciations but in an inverse way. What is more, this rising of the temperature would be the fastest in the last 100 thousand years, making the recovery and adaptation of the existing ecosystems a very difficult task.
The major change until now has occurred within the atmosphere. We have and are still changing the balance of the gases that constitute the atmosphere. This fact is especially notorious among the hot house key gases as the carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O). These natural gases conform less than a tenth of the 1% among the total amount of atmosphere gases, but nevertheless vital, because they act as a protective 'blanket' around the Earth.
The amount of energy received by the Earth from the Sun has to be balanced by the radiation emitted from the surface of the Earth. In the case of a lack of an atmosphere, the ground temperature levels will reach an approximate of -18 °C. This number is known as the effective temperature of terrestrial temperature, presently presenting an average temperature of around 15 °C.
The main reason for this difference of temperatures is that the atmosphere is almost translucent to the short wave solar radiations, but absorbs the major part of the long wave radiation emitted by the surface of the Earth. Several atmospheric components, such as the water vapour and the carbon dioxide, show molecular vibration frequencies within the spectral range of the terrestrial radiation which is emitted. These hot house gases absorb and re-emit the long wave radiation, then returning it to the Earth's surface, thus causing the rising of the temperature in a phenomenon that has been called the Hot House Effect.
The glasses that frame a hot house for plants works in the same way, it allows the passing of the solar light and shadows the radiation of the Earth, but it also confines the air inside, preventing the warm air from escaping. Nevertheless, the actual process involved is a different one and the name applied to it is a little tricky, because it implies that the air inside a real hot house is kept warm by the presence of the glass sheets, which inhibit the loss of heat through the convection towards the surrounding air. The atmospheric phenomenon is instead based upon a different process from that which takes place in a hot house, but the term has already gained a lot of popularity, thus being impossible to give it a more proper denomination.
One of the many existing threats to the life supporting systems is the direct consequence of the steady growth of the use of the resources. The burning of fossil combustibles added to the cutting of tree and the forest fires are carbon dioxide freeing agents. The increase in the amounts of this gas, among others, works like a trap for the solar radiation close to the surface of the Earth, hence causing a global heating. This could result, within the next 45 years, in a rising of the levels of the sea that could be enough to flood several low level coastal cities as well as river deltas. It would also cause an alteration in the International agricultural productions and in all the commercial exchange markets.
One of the consequences of the Hot House Effect is the collecting of much higher levels of water vapour concentration within the lower troposphere than those which would have been amounted if this phenomenon was not taking place. The scientists speculate that on the Planet Venus the volcanic activity raised the temperature up to a point at which the oceans were unable to condense, with the results that the accumulation of water vapour produced a Hot House Effect, which got indeed enhanced by the liberation of carbon dioxide from carbonated rocks, which at the end resulted in surface temperatures above 400 °C.
The great numbers of possible scenarios which describe the evolution of the human activities through the lapse of the next decades do allow us to perform several predictions regarding the components of a future climatic system. Relying on this data base and putting at work some of the most trustworthy models at hand, it is realistic to conclude that pending on a change of the present politics regarding the environment, the average temperature of the atmosphere at ground level will significantly increase along the 21st Century, hence involving a profound change upon the present climatic zones, consequently towing all of the regional climates as well as the agricultural , economical and utterly social infrastructures involved within.
The present society is characterised by many transcendental aspects, such as its compelling economical expansion, an increasingly growing rate of its demographical population, a technology that is still based upon the biggest profit available at the absence of a long term environmental policy, which is more and more a frenzied attitude to get a hold upon the environment than a will of living in harmony with it, an egocentric way of thinking that states that 'nature is a commodity for man'. Actually, instead of developing a healthy demeanour which would inspire mankind to accomplish a full integration within its natural environment by means of the respect and the search for better conditions for life without distinction over the face of the Earth, man has rather been steadily engaged in progressively developing some real time bombs for the forthcoming generations of the 21st Century and beyond.
Nature lacks the capacity for recycling the pollution of air, water and soil at the present rates to which the present society is submitting it, uncaringly disposing of the leftovers and residues from a technology which, at most of the times, can be addressed as uncaring, if not hostile, to the environment.
It would never be possibly attainable to talk with a total certainty about the characteristics of the future climate of the Earth because it will inevitably carry natural fluctuations, long term climatic changes and suddenly bursting phenomena, as the past records allow us to recollect. But it is a certainty that while the human society still remains unable to acquire a more profound knowledge of the climate system, of the interactions between its different components and of the external influences to which it depends on, it would never be possibly enabled to foresee with accurate certainty the effects of the intervention of man upon climate, a fact that deserves special attention, particularly regarding the study of the existing models as well as the reconstruction of the preceding climates.
USA is the greatest polluter of the world.
USA is the source of more than 30 per cent of the global emissions of different hot house gases. The numbers it shows, even at a per capita rate, are conclusive that it is also the greatest contaminating source.
The present report is a résumé of studies performed by:
||Emission per capita
(Equivalent in CO2 metric tons)
The Environmental Protection Agency (EPA).
Global Climate Change
Global Change: A Review of Climate Change and Ozone Depletion The Electronic Edition
National Geographic: Riddles of a Changing Climate
"Cambios en el Clima: Naturales o provocados?" "Changes in the Climate: Are they Natural or Man Made Occurrences?" By Benito PIUZZI