The carbon cycle can be defined as the continuous biological process through which the carbon is exchanged between the environment and the organisms. It also refers to the thermonuclear reactions which are brought about by nucleus of a carbon -12 atom when it absorbs protons. The sporadic climate changes being experienced in the world today are attributable to the disruption of carbon cycle in one way or the other. Top of the possible causes of this disruption are human activities. Nations are reluctant to accept their share of blame on the whole issue leading to a blame game. Unless the world unites against this common cause, the worst is expected to come. This paper covers the carbon cycle, how it works and how it's changing in response to human activities.
The way in which the carbon cycle works
Carbon is found in the atmosphere in form of the carbon dioxide gas. Other atmosphere gases which contain carbon dioxide include chlorofluorocarbons and methane. The lack or the improper functioning of this cycle can be very dreadful since plants and animals entirely depend on this cycle during their major biological processes. The work of the carbon cycle can be evaluated or assessed in accordance to the different processes that change or move carbon from one form to another. These processes are namely decomposition, photosynthesis, natural weathering of rocks, respiration and the ignition of fossil fuels. During the process of photosynthesis carbon which remains in the atmosphere as the carbon dioxide gas enters into the network of consumers and producers or what is referred to as the ecological food web. After its entry the photosynthetic organisms (algae, plants) absorb the carbon dioxide through the tiny pores found in their leaves. Via photosynthesis the plants can now use the absorbed carbon dioxide and convert it into simple sugars which are essential in the plants growth and reproduction. Plants also pass carbon to the animals especially when the animals feed o the plants since they do not have the ability to make their own food (Ryn and Cowan 87).
Respiration process is also found in the carbon cycle but it is unlike photosynthesis because it occurs in the decomposers, plants and animals. The respiration process also produces carbon because the component of oxygen is used in breaking down organic compounds into the carbon dioxide gas and water. Through this process of respiration carbon atoms which start out as the compounds of carbon dioxide are absorbed through the body of human organism and then passed to the atmosphere ready for another recycling. Decomposition happens to be the major process through which carbon is passed to the atmosphere in form of carbon dioxide. This is achieved through the use of decomposers (micro-organisms) which are mainly found in soil and water. These decomposers usually take in dead and waste products which are mainly found in form of rotting remains of animals and plants. At the same time they release carbon dioxide through the process of respiration. As earlier stated, weathering of rocks is the other process through which carbon atoms are released. For example the lime rock (an ocean floor stone formed by marine plankton shells) traps many carbon atoms. These carbon atoms are released sometimes after a million years when the ocean waters recede and the lime rock becomes exposed.
Scientifically, it's noted that when a lime rock is set out to the natural process of weathering it releases the already trapped atoms becomes a very active part of the carbon cycle once. Human activities/processes also increase the carbon dioxide in the atmosphere. One of these activities is the combustion of the fossils fuels. Due to the rapid expansion of industrial revolution many people have been burning the fuels which contain oil and coal to power their engines. The constant production of these fuels has resulted into huge amounts of carbon dioxide in the atmosphere. Most of the carbon dioxide produced by the combustion of these fuels is however absorbed by plants, oceans and soils thus reducing the increasing effects of global warming (Scienceclarified.com 1).
The human activities that influence the carbon cycle
Human activities have greatly interfered with the processes involved in the carbon cycle. An example of these human activities is deforestation. Deforestation is the removal of natural occurring forests through cutting and burning of trees in any forested area. People cut trees to use them as fuel, to use the land for pasture, farming and to build settlements. Active deforestation means that there will be no trees which emit oxygen while consuming carbon components (carbon dioxide). This leads to increased carbon dioxide than its consumed thus destroying the carbon cycle. The increase in carbon components in the air results into global warming (excessive heating o the earth's and oceans surface). This excessive heating results into dried rivers or decreased volumes of water in the earths surface because the hydrological cycle will be affected by higher rates of precipitation (Miller 217).
According to White (1203), the ecologies have greatly been changed by overgrazing, terracing, irrigation and the cutting of trees. For example he says that the Romans used to cut trees to build ships which were used to fight Carthaginians. He also states that the banks on the lower parts of the river Nile are now a human artifact instead of the African jungle which nature could have created instead of man. He also talks of historic ecological change which has been caused by the agricultural invention. Farming prompts deforestation because there must be cutting down of trees to create more space for farming. This ecological change will be contributed by the increase of carbon components in the air since the forest cover is not available. The green house kind of farming is one of the major agricultural contributors to the disruption of the carbon cycle. This is because the green houses emit gases which are not utilized thus bringing about global warming. Some of the gases emitted include the form of carbon referred to as chlorofluorocarbons. It therefore transpires that the amount of the carbon produced is higher than the amounts consumed.
Another human activity which has contributed immensely to the disruption of the carbon cycle is the combustion of fuels. This is because of the increased burning of fuels emits huge amounts of carbon components. This will lead to greater volumes of carbon dioxide in the air which will not be consumed thus making the carbon cycle in effective. White (1204) states that by 1925, London had experienced a smog problem which was caused by the continuous burning of soft coal. He also suggests that the current combustion of fossil fuels is high up to the point of threatening to change the world's atmosphere as a whole. White also suggests that war was another human activity which resulted in to ecological changes including the disruption of the carbon cycle. He asserts that the first cannon were fired in the early 14th century and this affected the ecology because workers were forced to the forests and mountains to scramble for more, sulfur, potash, iron ore and charcoal where by some resulted into erosion and deforestation. He also warns that a war fought with hydrogen bombs can alter the genetics of life. For example it will affect the processes of the carbon cycle between human beings and plants.
According to Mackenzie (1), fishing and whaling activities will affect the global carbon cycle. This is because the continuous removal of the marine biota has resulted into increased atmospheric carbon dioxide. She also suggests that the rise of carbon dioxide or carbon has been caused by progressive fishing which has caused biomass depletion of the world's ocean. Nowadays, the marine productivity is now relatively lower than it used to be when there was a maintained carbon balance in the ocean-atmosphere. Another form of human activities which have influenced the flow of the carbon cycle is air conditioning and refrigeration. This is because they utilize the carbon available in the air which is in form of chlorofluorocarbon thus inhibiting the continuity of carbon cycle between plants and animals. These human activities are however very important in the world because they reduce the effects of global warming by absorbing the extra carbon available in the air. Another human activity that has influenced the carbon cycle is the conversion of wild lands and agricultural lands into settlements. These human settlements are the major contributors to the increased emissions of the global carbon dioxide. They affect the carbon cycle through the direct emissions of the carbon dioxide resulting from combustion of fuels, the alterations of the plant and carbon cycles during the conversion of wild lands to urban and residential land cover and the indirect effects of urban and residential land cover on energy use ecosystem carbon cycling. In human settlements the soil carbon is lost through the soil disturbances caused by the conversion from natural to urban or sub-urban land cover type. The conversion of well settled and managed land cover into human settlements results into higher rates of carbon sequestration and storage due to large inputs of fertilizer, water and organic matter (Pataki et al 1).