Global warming refers to the rise in global average temperature caused by greenhouse gases such as carbon dioxide, methane, nitrous oxide, ozone, hydrochlorofluocarbons, hydrofluocarbons, chlofluocarbons and sulphurhexafluoride. Much like covering oneself with a blanket and feeling warm, greenhouse gases absorb infrared radiation from the sun which ensure favorable temperatures for living organisms and life processes. However, when such gases exceed acceptable concentrations in the atmosphere they absorb more heat and thus cause a rise in atmospheric temperature. In recent past, there has been growing criticism of whether global warming is real and more so that it has been caused by human activities.
As the global warming debate rages on, some facts about GHGs concentration stand out. According to Etheridge D.M. et.al (1998) the current concentration has been as a result of general increase of 49.4 ppm of CO2 from 284.3 ppm in 1832. As Blasing (2013) observed the increase is attributed to Industrial Revolution – an era when heavy reliance of fossil fuels led to more addition of carbon dioxide and other minor gases in the atmosphere. When burned these sources of energy release CO2 to the atmosphere. CO2 and other GHG gases trap heat and thus causing a greenhouse effect. Although clouds and water contribute about 36-72% of the greenhouse effect, CO2 and N2O are of particular interest since the two gases retain heat for much longer. The atmospheric lifetime of CO2 and N2O are 30-95 years and 114 years respectively while that of water is nine days (Jacobson, 2006). According to Intergovernmental Panel for Climate Change fourth assessment report (2007), with half of total carbon emissions being removed by half century, it means that more carbon is added to the atmosphere than it is being sequestrated. Nitrogen and other GHGs follow the same trend (IPCC, 2007).
Since more GHGs are being released to the atmosphere it means more infrared red radiation is trapped by these gases. Various impacts of rise of temperature as a result of greenhouse effect have been noted. Sea level rise is as a result of global warming. Studies have shown that the earth experienced sea level rise in the last century. What is surprising however, is that this rise is half the rate of sea level rise we have been experiencing in the last decade (Church & White, 2006).
Warming of oceans is yet another piece of evidence of global warming. According to studies by Levitus et.al (2009) there has been a general increase in the upper layers of ocean water. Their studies indicated an increase of 0.302⁰ F since 1969 within the top 700m of ocean water.
Glaciers, large masses of ice that form on high altitudes, have in been thinning or disappearing altogether as a result of global warming. These ice masses are very sensitive and can melt at the slightest temperature increase (Oerlemans, 2001). Pictures and satellite imagery of glaciers show decline of glacial sheets of the original all...