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Global Greenhouse

The greenhouse effect results from "the dirty of the atmospheric infrared window" by some atmospheric trace gases, permitting incoming solar radiation to reach the surface of the Earth unhindered but restricting the outward flow of infrared radiation. These atmospheric trace gases are referred as greenhouse gases. They absorb and reradiate this outgoing radiation, effectively storing some of the heat in the atmosphere, thus producing a net warming of the surface. The process is called the greenhouse effect. The various independent historical observational measurements conclude that the global average near-surface temperature has increased by about 0.5 degree centigrade over the past 100 years. This observed warming trend is continuing despite the influence of the Mt. Pinatubo volcanic eruption, which caused volcanic emissions to reduce incoming solar radiation for nearly two years. The likelihood that this global warming is due to primarily to natural variability is low. Scientists believe that this global warming trend is resulted from the enhanced greenhouse effect. The notion of an "enhanced" greenhouse effect refers primarily to the incremental global warming caused by the exponentially increasing concentrations of anthropogenically introduced greenhouse gases over and above the greenhouse effect caused by naturally occurring
greenhouse gases. Although there exist large uncertainties, scientists suggest that the emissions of greenhouse gases and sulfate aerosols could, by the end of the next century, lead to an increase in global mean temperatures of about 1-4 degree centigrate. According to a climate model from the Hadley Center for Climate Prediction and Research, in the United Kingdom, there is strong evidence that man-made greenhouse gas emissions are responsible for global warming over the past few decades, however, the sun and volcanoes played a significant part in effecting temperatures during the first half of the twentieth century. The main...