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The greenhouse
effect consequences |
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Forecasts The IPCC
has considered different possibilities concerning the variations of
greenhouse gases emissions during the next century, the average scenery
according to scientists of the United States, is as follows: growth of
population, continuous rise of the use of carbon (the greatest emitter of CO2
among the fossil fuels), modest developments in the use of energetic clean
renewable resources with a gradual decrease of 30% of the average emissions. In
such conditions it is calculated that the presence of CO2 in the atmosphere
will double within the end of the next century. Moreover, one must take into
account the "feedback effect" which occur when some changes in
temperature occur as a result of the increase of temperature which in turn
will lead to a further increase of temperature. Generally speaking this
situation will cause an increase of 2-3 degrees in the average temperatures
in North Africa, Western and Central Asia, Europe and the United States, and
an increase of 5-10 degrees in all the Sub-Arctic areas. The main factors of
the "feedback effect" are the following: ice and snow will melt and
larger and larger extensions of earth will absorb the solar rays, the earth
surface will get warmer and this will cause more melting of ice and snow. Higher
temperatures will intensify both the evaporation and the presence of steam in
the atmosphere. The latter is a powerful greenhouse gas and its presence will
cause a further increase of temperatures. The effect of the increase of the
clouds is not clear yet: on the one hand, these reflect part of the radiation
towards the space, on the other hand they also have a greenhouse effect which
retains heat and cause an increase of temperatures especially during the
night. Forests represent one of the biggest containers of carbon and their
function could be neutralised (for more details see the section on forests). A
great quantity of carbon could pass from the forests into the atmosphere in
the form of CO2. The interaction of all these factors is difficult to forecast
and makes the forecasting of the real effects of these phenomena more and
more difficult to predict. However, climate changes will quickly produce
unexpected and sudden changes. The IPCC thinks that among these sudden
changes are the melting of the ices on the Antarctic ice-cap, a change of the
movement of the sea-current and in particular of the Gulf stream which at the
moment heats up some areas of Europe. The above-mentioned areas could see a
sudden decrease of their average temperatures. It is clear that modest
changes in temperatures can cause dramatic local changes. The IPCC forecasts
a raising of the level of the seas of about 1 meter: in some areas it could
be 30-50 cm and in some others it could reach 2-3 meters according to the
difference in temperature and the oceanic currents. All the
catastrophes caused by these changes are part of an average situation,
however if emissions will not be reduced of 30% or if the feedback effect
will prove worse than it is forecast, the situation could be much worse. |
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THE
FORESTS -----------------NASA
Queesland fire Vegetation
is very sensitive to variations of temperature as many species need peculiar
ecological habitats and do not tolerate even small changes. An increase of 1
degree C. would be enough to eliminate many species which would have to
migrate or die. In many areas the sudden changes of temperatures could also
cause the extinction of these species. In brief: if some see a future
expansion of the tropical forests, what could on the other happen is that the
increase of temperatures which will take place in the next century could
cause a shift of some climatic areas: for example the climate typical of
medium latitudes will shift into the one of climatic areas about 160-640 km
north toward the poles. Such shift would be too sudden and as a consequence
some types of forests could disappear completely, as the IPCC has forecast. In
some areas of the temperate zones of the States there could be draughts which
will cause forests to burn and the proliferation of noxious insects. In the
tropical areas the increase of temperature and the variation of waterfalls
will also represent a danger for the preservation of forests. The strategies
so far adopted to protect biodifference will increase its vulnerability, as a
matter of fact biodifference on the planet is protected in National Parks and
reserves. But with sich change of climate these will be transformed into
traps and their peculiar eco-systems will perish. |
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PRAIRIES AND
PASTURE African
prairies in particular, which in the last 25 years have been subjected to the
worst draughts, in the future will be subjected to similar but worst
phenomena which will cause an acceleration of their desertification. If the
environment will become more and more arid and the ground will be subjected
to repeated erosion and will become more and more compact, the process of
desertification will be an irreversible phenomenon .In the South American
Pampas, the IPCC has forecast that agricultural production will diminish
drastically. All over the world the condition of the condition of prairies
and pastures will worsen, the content of carbon in the grass will increase
while the azote will diminish its nutritive values improving the development
of ligneous species, a tendency that is already started in the prairies. |
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THE
DESERTS Climatic
models suggest that deserts will become hotter and hotter, rainfalls, when
they come, will provoke floods and erosions. In these conditions survival of
animals and plants, which are already in unfavourable conditions, will be
threatened. NASA Salt lake Lop Nur North China |
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MOUNTAINS If the
species in the plains have to migrate about 150 km north to neutralise the
effects of the increase of temperature of 1 degree C., in the mountains these
will have to move 150-200 meter higher to obtain the same effect. The sides
of the mountain are characterised by different climatic habitats situated one
next to the other. If temperature increases, species will have to move toward
higher altitudes in a way that is proportional. For example, if the
temperature increases of 4 degrees, species will have to move 600-800 meter
higher. The consequences of this is that species who already live at very
high altitudes will risk extinction and moreover the species who will migrate
will be destined to diminish because the higher you get, the smaller the
habitat gets. |
THE CRYOSPHERE
The
increase of temperature will lead to the melting of the ice and of the
permafrost. Surfaces covered by snow will be reduced all over the planet. The
consequences of the seasonal melting of the snow and ice will be disastrous on
larger areas of the planet and will damage several human activities, from agriculture
to the production of hydroelectric energy. The IPCC suggests that the changes
in the cryosphere will be the most rapid and dramatic climatic changes. Within
the year 2100 from about 113 to half of the glaciers in the mountains could
disappear. 16% of the permafrost will melt by 2050 and these areas could
disappear completely in Northern Europe. By 2050 the whole of the Arctic coast
will probably be free of glaciers for five months a year and therefore could
become an economically developed area.
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LAKES
RIVERS AND HUMID AREAS The
idrological cycle will be quicker because the highest temperatures will cause
an increase of evaporation and will increase rainfalls. It will rain more on
the coastal areas, while in the continental regions and tropical areas
rainfalls will diminish. The eco-system in rivers and lakes will be effected
by the increase of the temperature. For example in the United States the
increase of the temperature of 2 degrees centigrade in the cold waters of the
rivers will reduce to one fourth the habitats and so the species will be
reduced as well. Changes in the rainfalls will also cause floods which will
erode the river-beds and impoverish the biomass for long periods. The humid
areas used to occupy 5% of the earth surface. Half of it has already
disappeared through land reclamation. As a consequence of the increase of
evaporation these will diminish even further. If temperature increases of 4
or 5 degrees the 85% per cent of humid areas in Southern Europe will
disappear and the great forests of Borneo will be dry for part of the year,
causing the peat to catch fire. This will destroy vast extension of forest
and will form, as it has already happened, a vast area of smoke which will
extend for thousand and thousand of kilometres. The effects of this
phenomenon would be particularly bad in the Arctic regions and in the tundra,
where the permafrost stops the ground to be drained. If the ices would melt,
large areas of peat will form and the ground will dry and pine trees,
sphagnum and lichen will disappear and will be substituted by grass. |
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COASTAL
AREAS AND SMALL ISLES The
consequence of the raising of the leval of sea waters and of violent storms
are terrible in sea areas . Nowadays 50 million people have had to suffer the
consequences of floods caused by storms. In the future, if the level of the
sea risers of one meter , this figure coult rise considerably. Researches
suggest that 17% of the total of the Bangladesh territory could disappear
threatening in this way the life of 70 million people. A similar situation
would occur in China . All over the world the rising of the level of the sea
will cause the receding of the coastal line endangering the existance of
sandy dunes, coastal lagoons and their habitat. The rising of the temperature
will also spread the risk of invasion of exotic species with disastrous
consequences. The coral rifts will be in danger ; this is very crucial
because despite the fact that they occupy only 1% of the whole surface of the
earth they host about 4-5% of the total of the species. Some studies
demonstrate that providet they are in god condition the coral rifts cannot
grow as much as the rise of the sea water. The ideal temperature for their
growth is about 25-28 degrees, and they are very sensityve to the increase of
temperature. The hot temperatures that have ben registered in the tropical
seas in these last years have caused the "bleaching" of the corals.
If this situation will not improve, it coult lead to their deaths. The atoll
represent , according to the IPCC , " a habitat which is very sensitive
to long period climatic variations and to the rising of the level of sea
waters". |
THE
OCEANS
The
heating of the globe will cause the rising on the temperature of sea waters,
especially surface waters, and will modify oceanic currents , waves and the
amount of salt. The changes which will occur on the emerged lands will
influence some of the changes whitch will take place in the oceans,
particularly in the coastal areas where the quantity and the quality of the
rivers will change drastically. The geography of the sea eco-system will also
change deeply with the consequence that some fishing areas will collapse and
some others will be very abundant, depending on the peculiar climatic and
oceanographic phenomena. The upstream currents wich carry the nutrients to the
surface will change according to the climatic changes in a way that is not clear
yet. However , it is feared that the rising of the temperatures on our planet
could weaken the oceanic circulation of water with a strong reduction of the
amount of nutrient we have on the surface of the oceans. The speed of these
changes is of fundamental importance. Within
50 years, the IPCC has suggestead that climatic variations could become more
dangerous than excessive fishing practices for the preservation of resources .
It will certainly be difficult to separate the effect of climatic variations
from excessive fishing practices. For exemple the disappearance of cod-fish off
the Canadian coasts has benn caused both by environment conditions as much as
an excessive fishing practices.
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AGRICULTURE Researches so far have shown that generally
speaking the effect on the agriculture world production will be minimal, also
thanks to the effects caused by a greater concentration of CO2 in the
atmosphere . However climatic changes will cause local variations of the
agricultural production. The areas that will be affectet more will be the
tropical and subtropical areas where the poorest people are. Agricultural
world production is not so significatnt as local agricultural production in
relation of phenomena such as famine and malnutrition.Moreover agricultural
production will depend on the capacity of farmers to adapt to the changes and
the changeable climatic conditions . All this could be an impossible
situation to face for developing countries with difficult and critical
realities. __________________NASA Victoria Australia |
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INDUSTRY AND INFRASTRUCTURES This sector, if it is well-developed,
should not be affected by climatic variations; moreover it is constantly
renewed by climatic variations; moreover it is constantly renewed and can be
adapted to changes. However, those infrastructures such as bridges, buildings
on low coasts will be endangered. NASA Bay Tokyo |
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HEALTH Climatic changes will be very damaging for man's health, and the mortality will be very damaging for man's health, and the mortality will probably increase due to these changes. In cities and in temperate areas in general more and more intense heat waves will cause the death of thousand of peoplefor respiratory and heart diseases. Some forms of pollution (pollen, spore and moulds) will get more and more dangerous. Hurricanes will cause more and more deaths. Potable water will be contaminated and the scarcity of water in some dry areas will cause some diseases such as famine and yellow fever to spread in areas where these did not use to be common. By 2100 the 60% of the world population will live in temperate areas which could still be hit by malaria. The sudden changes of the atmospheric pressure will influence men and plants: men will be more sensitive to pain especially muscular pain or pain caused by rheumatism. There can also be negative effects on the psyche such as sudden changes of mood, lack of concentration, depression and anxiety. |
