Global Warming is defined by Encyclopaedia Britannica as ‘potential increase in average global atmospheric temperatures resulting from the greenhouse effect.
‘ This is, literally speaking, incorrect; literally, Global Warming means ‘an increase in average global temperature’, which could be for any number of reasons e. g. the sun increasing in size (bringing it closer to the earth and thus increasing the intensity of radiation reaching earth) and/or the sun increasing in temperature (a greater amount of radiation being emitted would result in a greater amount of radiation being received).However, in my opinion as a result of media attention, when we talk of global warming, we are usually talking about the greenhouse effect.
The two potential issues mentioned above will almost certainly not become important for around a billion years, yet the greenhouse effect is, according to many scientists, already taking effect. Therefore, for us to be able to talk about global warming, it is important to have an understanding of the greenhouse effect. Electro-Magnetic-Radiation (EMR) is emitted by the sun, and contains light, as well as such things as infrared radiation and ultra-violet radiation.A small fraction of this radiation arrives at the earth’s atmosphere, where some of it is absorbed, but in the most part it passes through to the surface of the earth.
The molecules that make up the surface reflect much of this, but also absorb some. This increases the frequency of their vibrations; they are heated up. The heat dissipates out into the air around the surface and into the surrounding earth. Some of the energy is radiated back out; largely as infrared radiation because the particles don’t get hot enough to emit much light but neither are they cool enough to emit micro or radio waves.
Gasses in the atmosphere then absorb the radiation, or it passes through into space. Some gasses are more absorbent than others, just as some materials are opaque whilst others are transparent. In particular, gasses emitted naturally by volcanoes, largely COx, SOx, and NOx, are infrared absorbent but Hydrocarbons such as methane, a major constituent of ‘farts’, are major factors when talking about ‘greenhouse emissions’. Clouds, formed when water vapour condenses in the right conditions, absorb and also reflect large amounts of this radiation.
Water evaporates when heated, and in particular the sun evaporates a great deal of water.The water vapour, which is less dense than air, will rise and form clouds. Much of the EMR emitted by the sun can penetrate the earth’s atmosphere because the sun emits a great deal of light, and the atmosphere is fairly transparent at all stages. Some of it cannot get out because it is re-radiated as infrared, which is largely absorbed by the ‘greenhouse gasses’ and the clouds.
This is similar to the situation inside a greenhouse, which heats up because energy in the form of light passes through the glass, but cannot get out as much of it is converted into infrared, which the glass absorbs.Unlike a greenhouse, the greenhouse gasses do not prevent heat being conducted to outside of the earth, as energy can only exist as heat when it is absorbed by matter, and outside the earth there is a vacuum. It only stops radiation reaching the outside universe. There is growing concern amongst scientists that anthropologic activity could be increasing the quantity of greenhouse gasses in the atmosphere to an extent that is likely to have an effect upon the earth’s climate.
Certainly, the burning of fossil fuels produces around seven billion tonnes of CO2 per year, but the question is what effect this would have.In theory, less energy should be leaving the atmosphere, and so, in theory, the average global temperature would increase. For reasons including the prevailing wind direction and the way that heat is transferred, the areas that would be most affected are the poles where, the ice sheets which hold most of the world’s fresh water reside. If the temperature rises above freezing point for a long enough period of time, probably during the summer, then the ice caps partially melt.
The water would passes directly into the oceans that encircle the ice sheets.This happens every year naturally, but if global warming were occurring, the amount of ice that melts each year would increase to the point that less water freezes during the winter than melts during the summer. The more frequently this happens, the greater the amount of ice that would melt the next year as the reduced quantity of ice would mean an increased surface temperature. Eventually, the temperature could, in the Arctic at least, never drop below 0i??C, so not even the fresh water would freeze.
This is far less likely to occur in the Antarctic, as the land is considerably more mountainous, and there is a whole continent upon which the ice sheet rests, helping to keep the water fresh and its melting point high (relatively). Still, huge amounts of water would be released, raising sea levels well above their current levels. Raised sea levels would bring disaster upon ‘small island states’, as they would lose most of if not all their land to the sea. Ergo the organisation AOSIS (Alliance Of Small Island States) pushes for immediate action to be taken to prevent global warming.
Low lying land, such as the fens and most of Holland would also end up under the sea or become swamp-like marshes. Great Britain would lose much of its land, although Flitwick ; Ampthill might be okay, as just out of Flitwick is the shoreline from the last time there was a complete end to an ice age. An increase in the amount of fresh water in the oceans would dilute the sea, changing the average density of seawater. This would affect ocean currents, and could, long term, bring about another ice age almost immediately after if not before the present one ends.
Less salty water would also kill off much of the marine wildlife, thus annihilating most of the worlds oxygen supply. The loss of the ice caps would quite possibly lower temperatures in many parts of the world, as, for instance, if the Gulf Stream were to stop flowing, Northern Europe would lose much of the warm air it receives from the Gulf Stream. Other areas, such as California, may heat up, as a cold current flows down from the Arctic at present that may cease and send the mean temperature in the region to well above present day levels.So, if all this could happen, why do certain governments wish to continue producing, and even increase, the quantity of greenhouse gas produced.
The governments of certain LEDCs, such as India and China, claim that is unfair that they should not be allowed to develop just as the MEDCs did, but there is also resistance from MEDCs. There are three main reasons for this: 1. The cost of reducing greenhouse emissions to pre-industrial levels was estimated by a Dane named Nordhaus to be around 11,000 billion US dollars. The cost of ‘no change’ in greenhouse emissions would be 5,000 billion US dollars.
These figures are now ridiculed by many, as much of these ‘costs’ could be to taxation (people and businesses would pay more taxes on things such as fuel and energy), and these could be refunded on other taxes e. g. (income tax could be cut, or taxes on ‘green’ industries could be lowered dramatically). Perhaps unfortunately, the American Senate is made up of Americans, who, although they may have fantastic brains, aren’t the fastest to cotton on to ‘changes’, probably due to their inferior education system.
They are also politicians, who don’t want to admit that they were wrong in the past. . Sympathy with the LEDCs, and a desire to enter into their markets. 3.
The fact that there is a great deal of uncertainty as to whether global warming is occurring, and if it has anything to do with greenhouse gas emissions. So, is global warming taking place? Models have been produced to simulate the effect that greenhouse gasses will have upon the mean global temperature.The models described by the UN as ‘generally accurate’ in 1990 predicted that by 2000, the mean surface temperature should have increased by between 1. and 2.
3i??C since the late 19th century, with a higher figure for the northern hemisphere than the southern one. The currently observed warming is considerably lower. By 1995, (yes, it actually took them the best part of five years) the UN noticed that these models weren’t so accurate, “unless a lower climate sensitivity is used”.Also they said that “There is growing evidence that increases in sulphate aerosols are partially counteracting [the warming due to] increases in greenhouse gases.
Sulphate aerosols are emitted when fossil fuels containing sulphur are burned. They are tiny dust particles that reflect away the sun’s radiation before it can be absorbed by the surface. This reduces the amount of energy that can reach the surface, and so, even though a greater portion of energy received would be retained, less energy would be received. Because sulphate aerosols are usually produced along with greenhouse gasses, although in lesser amounts, it makes sense that they at least could be, counteracting global warming.
So, global warming could be caused by greenhouse gasses, but, because of the sulphate aerosols that are being produced along with them, global warming is at least being slowed, if not halted. Another factor could be forests, which in the Northern hemisphere are believed to be absorbing up to 25% of the total emitted. In some forests, tree growth is abnormally fast, yet in others, tree growth is much slower than before. This is believed to be to do with there being too much sulphur in the air and the soil growing acidic.
Both of these things can, at least in part, be explained by sulphate aerosols, so perhaps they’re not so great after all. Still, it seems unlikely that global warming is occurring due to the greenhouse effect at present, as the models that are used to try to measure its effect are clearly wrong for some reason or another. The only reason I can see for the constant reitteration of the greenhouse effect is that the average climatologist in the US is paid around one million dollars a year, and to keep getting that money, they have to say something that isn’t definite.By persisting with an idea that is particularly difficult to prove yet quite easy to disprove, they ensure their jobs will continue to exist in the future.
However, water has been found in recent years actually at the North Pole. This should be not happening if global warming were not taking effect, as this has never before been recorded. Or should it? How should we know? We haven’t been recording for any real length of time at all, relatively speaking. There are four main factors that have historically affected the average temperature on earth:1.
Life. The balance of the atmospheric gasses has a great deal of influence upon the temperature, and the atmospheric gasses are greatly affected by living creatures. In particular, plants release oxygen from CO2, but also, after animals and plants have died under the correct conditions and natural gas formed, a earthquakes are believed have to released huge quantities of gas suddenly with massive effect. There was nothing to change the gas into substances that plants could use, and there were too few sulphate aerosols to counteract the effect, and so global warming occurred.
Volcanic activity. When a volcano erupts, greenhouse gasses are emitted. These are hugely important for maintaining a temperature that can sustain life, although less so today. 3.
Pressure systems. There are places on the earth where the air pressure is always high or always low. This doesn’t usually have to do with the area so much as the prevailing wind and ocean currents should these move for any reason, the climate can be drastically changed. 4.
Astronomy. The Earth’s axis moves in an elliptical cycle called precesseion that lasts 26,000 years.This has a great deal of impact upon the seasons, which in turn affects the freezing and thawing of the ice sheets. In any one cycle, there are usually two ice ages and two ‘non-ice-ages’.
There is not a great majority though, as there were many periods an ice age lasted hundreds of thousands of years, and conversely, there were possibly many ‘non-ice-ages’ that lasted millions of years, although it’s difficult to tell exactly what happened that long ago (these periods were believed to have been during the time of the dinosaurs).Also, the planetary plane alters slightly on a 130,000-year cycle. This has less impact than precession, although it affects the effects that precession will have. This means that there are 1,690,052,000 (one-billion, six-hundred and ninety-million, fifty-two-thousand) possible alignments altogether, on a given day in a year, allowing for a great deal of variety in the climate as a result of this factor.
Finally, there are huge asteroids and comets that occasionally crash into the Earth and impact upon the climate.They throw huge amounts of dust up into the air, blocking out the sun’s rays. They create tidal waves that disturb the oceans where most of the oxygen is released and smother huge areas of land. Perhaps they even cause volcanic eruptions, throwing even more dust into the atmosphere.
A large enough rock travelling directly at the Earth or slightly in the opposite direction to its rotation will have an enormous impact upon the Earth’s climate. At the moment, then, which of these apply?Which of them, if any, explains the current situation where the mean temperature isn’t rising very much at all, yet the poles are melting? At the moment, only the coral reefs are dying, and even then only in some parts of the world where the temperature has risen by just a single degree. In other places, such as Barbados, new reefs are forming. On the whole, trees are growing faster than ever in the Northern Hemisphere, and there have been no catastrophic gas leaks in recent millennia, so there is little on the front of Life to be causing global warming.
There isn’t a great deal of volcanic activity at present, and the next really major eruptions are more likely to start an ice age than anything else. Precession, however, offers a slightly backward suggestion. We should now be moving toward this cycle’s second ice age. The first major ice age was ended abruptly, and in my opinion this is the truth behind Noah’s flood.
The best explanation for this abrupt ending I feel is a meteor striking the ice where it had frozen over the sea, leaving no trace, but that is not a provable hypothesis.Although we are already in an ice age, it isn’t a full-blown ice-sheets-in-Spain situation. We know that before an ice age, the mean polar temperature rises slightly before plummeting, and that lower atmospheric temperature falls before surface temperature. Lower atmospheric temperature tends to change before surface temperature, but initially to a lesser extent.
So what is actually happening at the moment? The computer models used to predict the effect of greenhouse gasses predict a rise in temperatures of around 0. 35i??C.Actually, since 1979, when recording of temperatures in the lower atmosphere first began, temperatures have fallen! However, the same thing happened between 1940 and 1960 with the surface temperature, so it could be a fluke. It may not be a coincidence that the temperature raised after 1960, though, as it was about this time that CFCs began to become widely used.
These gasses drift to the poles where they react with the O-Zone layer to leave a hole through which Ultra-Violet rays can pass. O-Zone (O3) is a gas formed when oxygen comes into contact with ultra-violet radiation or a spark passed through it.It is considerably less dense than air, which is fortunate because it is both poisonous and unstable; unless ultra-violet radiation or electricity is kept in contact with it, it breaks down into oxygen, which is why the O-Zone layer shields us from ultra-violet rays. As the O-Zone hole increases in size, so more UV rays can pass through.
This energy has to go somewhere, and I’ll wager that the ice sheets are absorbing a fair portion of this radiation, and heating up along with it. A quasi-flaw with this suggestion is that the Southern O-Zone hole is considerably larger than the Northern hole, and the melting is presently worse in the Arctic.However, this is less of an issue than it may at first seem due to the fact that the Antarctic is considerably colder and much of the ice will have a higher melting point due to the reduced percentage in contact with the sea. Or perhaps this is all a load of rubbish and it’s just a coincidence that the ice sheets are melting.
In the 17th century, we know that people went ice-skating on the Thames. It seems unlikely that there was an unusually small amount of greenhouse gasses during this period, and so perhaps the earth just naturally changes in climate.The Thames hasn’t frozen over to an extent that you could go ice-skating on it at all this century, not even during 1940. It is true that the hottest summers since records began were nearly all this decade, but records only began in 1880.
Bearing in mind the possible number of combinations for the alignment of the poles on a given day in a year (1,690,052,000), 120 years worth of results is hardly going to help when determining what is going to occur at a time such as the one we are potentially facing; a time of climatic change. We must also bear in mind, however, that we may not be heading toward anything other than usual.