The Carbon Cycle
You will see the carbon cycle drawn in many different ways and in exams they nearly always come up with a new diagram. It is really important that you understand the carbon cycle well so that you can interprete any diagram you are given. Here is a nice one.
The Effect of Humans
The context of the course is the effect of humans on the environment. So, it is important that you understand how humans affect the the carbon cycle.
Carbon has been cycling naturally as long as the Earth has existed. Infact, early in the Earth's life the atmosphere was made mostly of Carbon Dioxide. Now most of the Carbon has been 'locked up' in what we call Carbon Sinks. These include trees, rocks (like limestone) and fossil fuels; Coal, Oil and Gas. It is when we interfere with these that we interfere with the Carbon Cycle.
Carbon has been cycling naturally as long as the Earth has existed. Infact, early in the Earth's life the atmosphere was made mostly of Carbon Dioxide. Now most of the Carbon has been 'locked up' in what we call Carbon Sinks. These include trees, rocks (like limestone) and fossil fuels; Coal, Oil and Gas. It is when we interfere with these that we interfere with the Carbon Cycle.
Deforestation
Deforestation is the permanent destruction of
indigenous forests and woodlands. The term does not include the removal of industrial forests such as plantations of gums or pines. Deforestation has resulted in the reduction of indigenous forests to four-fifths of their re-agricultural area. Indigenous forests now cover 21% of the earth's land surface.
WHAT ARE FORESTS AND WOODLANDS?
In a forest the crowns of individual trees touch to form a single canopy. In a woodland, trees grow far apart, so that the canopy is open.
GOING, GOING GONE!
Of great concern is the rate at which deforestation is occurring. Currently, 12
million hectares of forests are cleared annually - an area 1,3 times the size
of KwaZulu/Natal! Almost all of this deforestation occurs in the moist forests
and open woodlands of the tropics. At this rate all moist tropical forest could
be lost by the year 2050, except for isolated areas in Amazonia, the Zaire
basin, as well as a few protected areas within reserves and parks. Some
countries such as Ivory Coast, Nigeria, Costa Rica, and Sri Lanka are likely to
lose all their tropical forests by the year 2010 if no conservation steps are
taken.
Deforestation is a problem, in terms of the carbon cycle, because photosyntesis is the only way of removing carbon dioxide from the atmosphere. Not only that, but the trees are often burned or left to decompose. This releases carbon that has been locked up for hundreds of years into the atmosphere. In short, more carbon dioxide is released and less is absorbed.
Deforestation is the permanent destruction of
indigenous forests and woodlands. The term does not include the removal of industrial forests such as plantations of gums or pines. Deforestation has resulted in the reduction of indigenous forests to four-fifths of their re-agricultural area. Indigenous forests now cover 21% of the earth's land surface.
WHAT ARE FORESTS AND WOODLANDS?
In a forest the crowns of individual trees touch to form a single canopy. In a woodland, trees grow far apart, so that the canopy is open.
GOING, GOING GONE!
Of great concern is the rate at which deforestation is occurring. Currently, 12
million hectares of forests are cleared annually - an area 1,3 times the size
of KwaZulu/Natal! Almost all of this deforestation occurs in the moist forests
and open woodlands of the tropics. At this rate all moist tropical forest could
be lost by the year 2050, except for isolated areas in Amazonia, the Zaire
basin, as well as a few protected areas within reserves and parks. Some
countries such as Ivory Coast, Nigeria, Costa Rica, and Sri Lanka are likely to
lose all their tropical forests by the year 2010 if no conservation steps are
taken.
Deforestation is a problem, in terms of the carbon cycle, because photosyntesis is the only way of removing carbon dioxide from the atmosphere. Not only that, but the trees are often burned or left to decompose. This releases carbon that has been locked up for hundreds of years into the atmosphere. In short, more carbon dioxide is released and less is absorbed.
Fossil Fuels (find out more)
Fossil fuels are another problem. Carbon that has been 'locked up' in the form of coal, oil and gas for millions of years is released when the fuels are combusted (burned). Combustion of coal, oil and gas is most significant in power stations where huge amounts are burned in order to generate electricity. In short, stored carbon is released and the amount of carbon in the atmosphere increases.
Fossil fuels are another problem. Carbon that has been 'locked up' in the form of coal, oil and gas for millions of years is released when the fuels are combusted (burned). Combustion of coal, oil and gas is most significant in power stations where huge amounts are burned in order to generate electricity. In short, stored carbon is released and the amount of carbon in the atmosphere increases.
What's so bad about Carbon Dioxide?
If you haven't taken geography you might need a quick lesson. here's the problem in a nutshell: