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Can the release of CO2 and other gases change the climate of the earth?

Light and other radiation from the sun hits the earth and heats it up. At the same time the core of the earth also produces some heat. The heat radiates from the earth as “long-waved heat beams”, infrared radiation, and thus the earth cools down.
If this radiation were to escape, the earth would have a mean temperature of -18°C !
Some of the heat waves are absorbed by greenhouse gases; Vapourized water, Carbondioxide, methane, ozon, N20, KFK-gas and and some other gases (C2F6, SF6 CF4)

These gases let at lot of the short-wave radiation from the sun onto the earth, while they impedes some of the long-waved radiations in getting out . When the green-house gases have absorbed the hest beams, they send them out again. Some back to the earth, and some out in space.
These gases function at the same way as the glass in a greenhouse.

• The heating of the earth on behalf of these gases are thus called the greenhouse effect.
  
• This is the explanation why the mean temperature is around +15°C and not -18°C!
  

The green house effect is not a disaster, but a condition essential to all life on earth!

Vapourized water is the most important greenhouse gas. About 90% of the effect comes from the evaporated water. But CO2 also counts a great deal. Gases like methane, ozon and KFK has together the same effect as CO2 .

The amount of vapourized water is only by small degree directly affected by human activity. CO2 and the other gases are more or less made by humans, and those are the ones we should emphasize to do something about. If we let more of these gases into the atmosphere, the temperature on the earth will rise.

The amount of CO2 consumed by the plants through photosynthesis is equivalent to the amount let out by cell metabolism. The increase of CO2 is caused primarily by the increased usage of ”fossil fuel” ; Coal, oil and gas in indusrty and house heating.in addition, more CO2 is released when woods are chopped to the ground and burned. In periods, also volcano eruptions can feed the atmosphere with large quantities of CO2 .
Of human made CO2 , the ocean consumes about half of it, and the plants use part of it in increased photosynthesis (among other places, this happens in northern forests)
It is difficult to explain where all CO2 goes. But a lot stays put in the atmosphere and can lead to increased temperature.

Methane comes from rice fields, swamps (biproduct of bacteria activity), farm animals (biproduct of metabolism) and industrial gas production.
1 Kg methane gas contributes more to the greenhouse effect than 1 Kg CO2, and the amount of methane is increasing more than the amount of CO2. Though, methane is more easily broken down than CO2.

Ozone is made in the atmosphere when UV-radiation hits oxygen gas ( O2) this happens about 15-40 km above sea level. When the energy-rich UV-beam hits the O2 molecule, ozon is made:
1) O2 - UV -> O + O
2) O + O2 -> O3 (ozon)

The ozon is broken down by KFK-gases. The chlor atoms regains its shape and thus can one molecule of KFK cause great damage over long time. KFK-gas is found in old refrigerators and freezers. On the dump, they leak out this gas which is very damaging to the atmosphere. Nowadays, such gas is forbidden to use and old refrigerators have to be handed in to special dumps.

Since Ozone is a greenhouse gas, a reduction of the ozone layer will at the same time make the greenhouse effect lesser. The ozone layer has been reduced with 5% since 1969..
The ozone down on the ground has increased due to human activity. KFK destroys as mentioned the ozone layer. KFK is a gas only produced by humans.

Few doubts that the amount of greenhouse gases has increased after the industrial revolution. But what connection is it between the increase of greenhouse gases and the temperature?

On the figure we see how the amount of CO2 and the temperature has changed from 1850 to 2000. Both curves has risen, but rhe shapes are not quite the same.
Great uncertanty is connected to these curves. We cannot on a basis of these decide whwther the temperature has rised because of the CO2- level, of if the CO2-level has rised because of the temperature.

Though more relations shows that a part of the increase of temperature we`ve had during the 1900-s are due to increased CO2-amount in the atmosphere.
IPCC (UN`s climate comite ) has suggested that if the release of CO2 continues as now, it could lead to an increase in temperature of 0,3°C per decade. Thus, the temperature can increase to about 3°C up to year 2100.

It is very difficult to calculate how the temperature on earth will change as a consequence of more greehouse gases let out to the atmosphere. Even if we know how much CO2 we`re going to release, there are many uncertain factors:

Increased temperature will lead to increased evaporation from the ocean. Vapourized water is a greenhouse gas which can make the temperature increase even more. But due to increased evaporation the number of clouds would also be greater. Which of these effects will be prevailing?

• How much CO2 can the oceans absorb? Huge amounts of CO2 can be dissolved in the ocean. Some binds to plants by photosynthesis and follows the food chains, and some become sediments when dead organisms sink to the bottom in lakes and oceans
• Will increased temperature lead to faster cell metabolism, faster than the photosynthesis, so even more CO2 is released?
• Will higher temperature affect the number of plants that grow above earth, and thus effect the amount of CO2 bound by photosynthesis?
• Will higher temperature lead to increased breakdown in swamp areas, and thus huge amounts of methane will be released?
• It seems that the earth is going towards a new ice-age. Will the increased temperature neutralize this, and keep the heat on todays level?

Another relation that causes great uncertanty whwn future climatic changes are concerned is the formation of particles in the atmosphere: Condensed SO2 particles from burning of coal , and dust particles whirled up from the earth. These particles reflects sunlight and thus hinder heating of the earth; they probably have a great cooling effect. Will this contribute to decrease the greenhouse effect, and do we want this particles in the air, as cooling as they might be?

In addition to this, natural climavariations (variations not caused by man) explain a part of the temperature increase we have observed during the last century. The radiation of the sun always varies and affect the climate of the earth.

Temperature increase is only one of the consequenses of increased amount of greenhouse gases. Other climatic relations, such as precipitation , humidity and wind, can also change considerably . Nowadays we will probably experience greater changes in the climate..
Storms, extreme dry periods and extreme periods of cold may occur more often. In europe, the climate can get more favourable for plant production than it is now., while in southern parts of the world, it can get more difficult to grow plants. It seems that the greenhouse effect at this point favours the richer countries, and if these canges should happen, will the suffering of the poor countries in the south be given sufficient aid?

In an ecosystem, the species always affect each other through competition, trophic interactions, symbiotic relations etc. If the conditions changes, the competition also changes, and some species may og extinct.

More greenhouse gases can thus indirectly decrease the biological diversity:

• An increase of temperature by a few degrees in 100 years could mean that species who earlier could not live in an area because it was too cold, now can compete and establish . The consequence could be that species who used to live in the environment goes extinct, among those ”key species” to whom many other species are essential for surviving.
• Changes in humidity and other climate changes can also effect the variation and spread of species.
• CO2 is as mentioned partly dissolved in water and forms carbon acid, thus the pH decreases. This is a change that could be fatal for species sensitive to it.
• Some plants (C3-plants) are more dependant of a large quantity of CO2 than other plants ( C4-plants) the C3-plants will get better conditions when the amount of CO2 increases.. Will maize lose its position in advantage for soya and oat? This may lead to change of feeding habits among animals and humans.

It has been a concern that the ocean might rise if the temperature increases. Ocean water expands when the temperature is higher, and glaciers will melt.

• How much will the temperature rise on the poles? Will a more hot environment lead to climatic changes that gives more precipitation over the poles? If so, that will compensate for some of the loss of the melting.
• How much ocean ice and how much ice above water will melt? The ice that now is situated on and in water, will not make the ocean level rise if it melts.

5 -Figure shows only canges due to thermal expansion alone

"Scientists disagree about the level of the ocean rise we might be facing, but low lands in ex. Bangladesh and some island groups may be under water in a while. This would be disastrous for the island and low-land population.
Well, it used to be warmer during the early medieval, and people got by then. But the earth is 20 times as dens populated now, and even denser along the coast. People could move into the country when the ocean rose. To move from a rising ocean today causes problems of ethnic character we never before had to face."
(direct translation from www.dagbladet.no/kultur/1999/07/17258.html)

The greenhouse effect is a big ”risk”, though its probability is not quite 100%
If we risk to wait preventing it until it has been 100% proven, we might be buying a lightning conductor after the stroke of lightning.
Nature has not only one side of the story, and we may only know a fracture of the greenhouse effect, But it is a strikingly strong tendency that the temperature rises with the amount of CO2-gas in the atmosphere.

Imagine that you come home to your apartment, and it is way too hot. If you want the temperature to be 18°C, you have to turn down your thermostate to 18°C.
But if you in addition to this have also have the sun shining through your window, you have to turn down the temperature even more, amybe as much as 6°C, to ever gett he temperature down to 18°C again.
Now you replace your housetemperature with the earths climate, your oven with the greenhouse effect , your thermostate with CO2 let out in the atmosphere, and the sun with other mechanisms effecting the climate, but which are out of our hands to control…….

A reduction of greenhouse gases let out by industry is absolutely necessary, no matter how many factors involved in the earths climate processes.

Sources:

• Article in Dagbladet, net edition: www.dagbladet.no/kultur/1999/07/17258.html
• www.miljostatus.no
• Hernes/ Skarning: Biology
• figures: http://www.gfdl.gov/~tk/climate_dynamics/climate_impact_webpage.html

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