Climate is defined as the main physical state of the climate system. The climate system is constituted by atmosphere, hydrosphere, cryosphere, lithosphere, and the biosphere, which are intimately interconnected (Lauri, 80). Climate characteristics are defined by data collected over a long period, which in most cases is beyond 50 years. Date collection that determine climate revolves around the climate system, its behavior and structure of the particular predetermined period and the interaction of the various components of the climate system (Jehlicika & Jehlicika, 128). The atmosphere is the main component of the climate system, which consists of nitrogen gases (78% of the atmosphere), oxygen (20.9 %), and argon (0.93% volume mixing ratio). The aforementioned gases have been documented to have little or no interaction with infrared radiations emitted by the Earth. However, the three mentioned gases are not the only components of the atmosphere. Other gases such as carbon dioxide, methane, nitrous oxide, and ozone are part of the atmosphere. These gases interact with infrared radiation from the sun as the radiation is rising from the Earth’s surface. The aforementioned gases are commonly referred to as greenhouse gases, and are responsible for global warming that has adversely affected the world climate. According to Jehlicika & Jehlicika, 96, greenhouse gases play a major role in the energy balance of the climate system.
Generally, the sun is the main source of energy that drives the climate system (Walker et al, 36). Empirical literature suggests that the volume of solar energy reaching the atmosphere each second on a square meter of the earth’s surface is 1370 Watts. This energy averaged with relation to the entire planet has been estimated to be one quarter of 1370 Watts (Kiehl and Trenberth). It has further been said that 31 percent of this energy that reaches the planet’s atmosphere is reflected back to space through the clouds, aerosols, and rain. However, due to greenhouse gases that interact with solar radiations and infrared radiations, the atmospheric temperature raises (Odeku, 245). As heat is being reflected from the Earth’s surface back to the atmosphere, greenhouse gases traps this heat within the earth’s atmospheric space. It leads to an increase in the levels of temperature; a condition now known as global warming or greenhouse effect. It results to an imbalance in the energy level, which as a result, brings a warmer earth atmosphere and a colder upper atmosphere (Gillard, 89). Notably, it is necessary to have a balance between incoming solar radiations and outgoing solar radiation for a stable climate; however, this has not been the case, hence recent global concern of the rapid climate change (Odeku, 87-89).
What has Led or is Leading to the Alarming Climate Change?
Climate change has been of particular interest to the International community in the recent past due to the rapid changes, which have been predicted to be dangerous. In one of its reports, the Intergovernmental Panel on Climate Change in 2007 placed 90 percent probability of global warming on human activities, however, this has received much criticism from a huge number of scientist all over the world (Odeku et al, chapter 13). Besides human activities, they are other factors that have been known over the years to cause climate change. These factors include internal dynamics, which are a natural occurrence and external forces that influence climate change.
External forces include human activities that affect the climate which lead to induced climate change, volcanic eruptions, and solar variations (Odeku al, 96-99). Solar emission alters the climate system. Various factors can determine the amount of solar emission. They include change in position of the Earth’s orbit or the Sun and a change in the amount of solar emission that is reflected. It may happen by changes in cloud covers or vegetation cover, and by altering the waves sent from the earth back to space through human activities such as greenhouse gas concentration (Odeku, 96-99).
However, regarding the factors causing climate change the emphasis has particularly been laid on human activities causing greenhouse effect and deforestation. Nevertheless, a group of scientist (Lauri, 210) has also criticized this sharply. A response released by the Centre for the Study of Carbon dioxide and Global Warming change stated that there is no doubt that the amount of Carbon dioxide ratio in the earth’s atmosphere has risen significantly since the beginning of the industrial revolution and that the Earth’s temperature has increased slightly during the same period. The center also indicates no compelling reason attributing to the rise in temperature to carbon dioxide since the notion of global warming is a result of increased carbon dioxide (Odeku, 16).
The George C. Marshall agrees that human activities have increased the carbon dioxide amount in the atmosphere. However, he disagrees with the notion that the amount of carbon dioxide produced in the resukt of human activities is enough to make alarming climate change (George C Marshall, 2009, 4). He relies on recent satellite measurement data of the sunlight that is reflected from the clouds, and infrared heat given by the earth suggest that water vapor and clouds may reduce the effect of Carbon dioxide produced by human activities (Negative feedback). Satellite measurement feedback being negative means that the carbon dioxide produced from human activities is negligible to have a large effect on climate change. Therefore, he draws from that information that they are natural flows of carbon dioxide and they much more than that produced by human activities.
On the other hand, scientists from the United Nations Framework Convention on Climate Change (UNFCCC 2010 Report) states that the main reason for an increase in temperature is a rise in industrial activities in the past one and half century. Through industrial activities where fossil fuel is burned and greenhouse gases produced through interaction such as: gasoline, coal burning, tree cutting and modern land use age. The report acknowledges that the greenhouse gases are produced naturally but the balance of the natural amount has been offset by human activities. It led to the increase in the global temperature since the gasses are able to trap heat from the atmosphere (United Nations Framework Convention on Climate Change Report 2010, 17).
Scientist from the United States Environmental Protection Agency (EPA) commented on global warming and climate change in 2009 and supported its argument on global warming and climate change on human activities (EPA 2009, 10)
It is apparent that there is a lack in consensus by a scientist in the area of Climate science on the cause of global warming and climate change in the recent past. This can be evidence by opposing directed to the Intergovernmental Panel on Climate Change report of 2009, which pointed that 90% of the climate change and global warming results from human activities (Jehlic?ka, 2). However, this has not stopped this notion that human activities such as burning coal, gasoline, oil and change in land use has led to increased temperature.
Over the years, climate change has been alarming and scientists have warned that this could lead to extinction of certain plants and animals. The theory behind climate change for many years has pointed to human activities, which are still held by a majority of scientist. Humans influence the environment they live in. Since the beginning of the industrial revolution, the effects of human activities on the environment has accelerated to a much larger scale globally (US Global Change Research Program 2010 Report on Global Climate Change). Human activities particularly industrial and domestic activities that involve the combustion of fossil fuel have increased which as a result produce greenhouse gases, aerosols and chlorofluorocarbons that trap heat in the atmosphere that result to changes in the temperatures and also destruction of the protective ozone layer (Jehlicika, 124). In addition, climate change has been credited to land use change. Land use change refers to activities such as deforestation, re-forestation, a forestation and modern methods of agriculture and use of fertilizers. These activities have had certain effects on the carbon cycle hence altering the normal carbon cycle (Filho, 92-93). Consequently, this leads to a reaction in the climate system hence climate change. Another human induced activity is the emission of aerosol, which is as a result of greenhouse gases interacting with infrared radiations. Aerosol brings about the scattering of solar radiation back into space (Filho, 94). It often offsets the energy balance, which in turn increases the greenhouse effect. In addition, some aerosols such as soot have been overtime to affect the density and side of clouds and these further results to the rate of solar absorption, which further offsets the energy balance (Filho, 91). Therefore, it is correct to say that though there are other factors that lead to climate change, human activities have led to global warming.