According to Kortmann, R., Peijnenborgh, E. (2007), sunlight is one of the major sources of energy for living organisms. Apart from helping us with various energy needs, it also helps in keeping the atmosphere warm. When sunrays strike the surface of the earth, they are partly absorbed, and partly reflected back into the atmosphere. These reflected rays, known as infrared radiations, are captured by 'greenhouse gases', which helps in keeping our atmosphere warm. These greenhouse gases are carbon-monoxide, carbon-dioxide, methane, and water-vapors. Although, these gases form only around 1% of our atmosphere, they are extremely vital in maintaining the ecological balance and sustaining life on this planet. Without the presence of these gases, the temperature of the earth would be 30°C lower, which means that survival of living species would not be possible.
The greenhouse effect can be thought of as a process through which nature maintains a balance in the atmosphere. However, human activity in the past hundred years or so has caused an increase in the percentage of greenhouse gases in the atmosphere, which has in turn increased the average temperature on earth. In the atmosphere, gases such as water vapor, carbon dioxide, ozone, and methane act like the glass roof of a greenhouse by trapping heat and warming the planet. These gases are called greenhouse gases. The natural levels of these gases are being supplemented by emissions resulting from human activities, such as the burning of fossil fuels, farming activities and land-use changes (Garnett, 2006). As a result, the Earth’s surface and lower atmosphere are warming. Even small rises in temperature are accompanied by many other changes. Rising levels of greenhouse gases are already changing the climate.
The most significant greenhouse gas is CO2. When fossil fuels such as oil, coal and gas are burnt, CO2 is released into the Earth's atmosphere. The cutting down of forests also increases the concentration of CO2 in the atmosphere, as growing forests remove CO2 from the atmosphere by absorbing it in wood, leaves and soil. This CO2 is released back into the atmosphere when forests are burnt (Garnett, 2006). The human activities of deforestation and fossil fuel use are the major anthropocentric causes of climate change.
Since the mid-1800s, the average global temperature increased by about 0.6 degrees C, impacting the entire world (Acts, 1998). According to McCarthy (2001), during the 20th century the global mean sea level rose by 10 to 20 cm, the overall volume of glaciers in Switzerland decreased by two-thirds and Arctic ice thickness in late summer and early autumn decreased by about 40%. Other significant observed changes include: i) a 40-60% decrease in total available water in the large catchment basins of Niger, Lake Chad and Senegal; ii) the retreat of 70% of sandy shorelines, and iii) a northward movement of some 100km of Alaska’s boreal forest for every 1 degree C rise in temperature.
Moreover, current climate change has already made “refugees” of two communities. The Lateu settlement, located in the Pacific island chain of Vanuatu, and the Shishmaref village, located on a small island in Alaska, were recently relocated – the former to escape rising sea levels, the latter degrading permafrost (McCarthy, 2001). It's clear that there are connections between climate change and the movement of people, but the connections are not as clear as the "climate refugee".
According to Acts (1998), Computer models