Definition of the Term of Global Warming
Global warming is the growth in the average temperature of the planet’s near-surface air and water recourses and its expected continuation. The average temperature of near-surface air has increased by 0.74 ± 0.18 °C (1.3 ± 0.32 °F) during the past several decades (Mendelsohn, 1999). The climate system is influenced by natural, internal processes, solar activity, volcanic activity, changes in the planet’s orbit (orbital forcing), aerosols, activities related to land usage, and greenhouse gases. The global warming process has resulted in the Earth energy imbalance, more energy coming in than is going out (Mendelsohn, 1999).
Causes of Global Warming
Greenhouse Effect
The causes of global warming may be a result of the growth of greenhouse gases level due to human activity as the main aspect. The greenhouse effect means the process of consumption and emission of infrared radiation by gases contained in the air that increase the temperature of the Earth near-surface air, oceans, and surface. Greenhouse gases result in the natural greenhouse effect (Christianson,1999). Human activity causes anthropogenic emissions the major of which is deforestation. The recent reports of science communities from all over the world state the observation of an increase in the intensity of tropical cyclone activity in the North Atlantic Ocean starting from the 1970s related to the increase in sea surface average temperature, but that the result of long-term observations which are complicated by the quality of information before the routine examination (Christianson,1999). But scientists also claim that there is no clear impact on the annual worldwide quantity of tropical cyclones.
Feedback processes
The major feedback effect is caused by the evaporation of water. The reversing process of this effect will take a long period of time as CO2 has a long lifetime in the atmosphere.
Another feedback effect is ice-albedo feedback. The growth of CO2-level results in the melting of ice near the poles. As the ice melts, its position is occupied by land or water which are more influenced by solar activity. This process increases temperature, which in turn results in more melting (Mendelsohn, 1999).
The thawing permafrost releases additional CO2 and CH4 and also contributes to the increasing in average temperature.
Solar Output
Differences in solar activity, possibly together with cloud feedbacks, may also have influenced the increasing level of global warming. An increase in solar output results in warming of the stratosphere while the greenhouse effect should provide a cooling effect on the stratosphere. The interrelation of solar activity and volcanoes has probably resulted in an increase in temperature from pre-industrial times to 1950, but since 1950 has resulted in a decrease in the temperature process (Johansen, 2002). However it could be stated that even considering increased climate sensitivity to solar output, most of the warming effect refers to the growth of greenhouse gases level.
Current and Expected Effects of Global Warming
Some effects on nature and human life are already referred to global warming process. Already stated effects that refer to the process of global warming include: glacier melting, ice shelf disruption, sea-level rise, impacts on rainfall patterns, and frequent extreme weather events (Johansen, 2002). While variations are projected for overall issues, intensity, and frequencies, it is not possible to refer specific events to the global warming process. Other expected effects relate to the lack of water in some regions and increased precipitation in others, mountain snow coverage variations, and health problems referred to as an increase in temperature.
Additional expected processes related to global warming process comprise sea level increase of 110 to 770 mm (0.36 to 2.5 feet) in the period between 1990 and 2100, influence on agriculture, possible decreasing of the thermohaline circulation, reducing of the ozone layer amount, frequent occurrence of hurricanes and extreme weather events, reducing of ocean pH level, and the expansion of diseases such as malaria and dengue fever (Johansen, 2002).
References
Christianson, G. E. (1999). Greenhouse The 200-Year Story of Global Warming. New York: Walker.
Johansen, B. E. (2002). The Global Warming Desk Reference. Westport, CT: Greenwood Press.
Mendelsohn, R. (1999). The Greening of Global Warming. Washington, D.C.: American Enterprise Institute.
Rye, J. A., Strong, D. D., & Rubba, P. A. (2001). Global Warming and Ozone Layer Depletion: STS Issues for Social Studies Classrooms. Social Education, 65(2), 90.