Topic 1: “Climatic Changes”

The carbon cycle

In the abiotic environment Carbon is part of the Carbon dioxide molecule CO2. Most of the CO2 is dissolved in the oceans but some exist in the atmosphere. Some of the organic carbon is released to the atmosphere as carbon dioxide through cellular respiration. Photosynthesis and cellular respiration are complementary processes, therefore this phase is often called Carbon-oxygen cycle.

 Like many other substances, the earth needs to recycle its carbon because it is not receiving any new supplies of it. Carbon is used up and returned to the environment in many different ways. Through greater use of fossil fuels and burning of forests we are responsible for a change of the global carbon cycle. Caused by these human activities large amounts of CO2, which are well above that of the natural cycling, are released into the atmosphere. The destruction of vegetation through humans reduces the capacity for photosynthesis which leads to a decrease of the volume of carbon dioxide removed from the atmosphere.

Greenhouse effect

Ultraviolet rays from the sun are converted into radiation of a longer wavelength. Large amounts of carbon dioxide are being emitted into the atmosphere. This gas acts as a shield trapping an increased amount of longer infrared wavelengths. This causes an increase in the earth´s overall temperature. Because of holes in the ozone layer, even more U.V. rays are entering the earth which increases effects like the rising of the water level, melting of the polar caps and developing extreme seasons (hot summers, mild winters).

The greenhouse effect and the Carbon Cycle

Pollution from cars and factories for example risers up into the atmosphere and builds up some kind of layer. Normally the sun´s heat is reaching the earth and going back into the atmosphere but because of this layer of pollution the heat stays on earth and cannot go back into the atmosphere. Consequences for that greenhouse effect are the rising of global temperature, melting of polar caps, increase of the sea level, extreme seasons. When forests are burned for agriculture carbon dioxide is added to the atmosphere as well as dust and ash. These solid particles deteriorate the albedo (=Rückstrahlvermögen) of the atmosphere, higher the solar radiation input and achieve any potential greenhouse warming.