global warming
...use effect". All climate models further predict that temperatures will continue to increase in the future, if human emissions of greenhouse gases continue and there are no significant changes in solar output or volcanic activity. 4. Relevant information from my research: Statistics 3 - 25000 years temperature trend 4 - Global temperature trend Global warming – the mechanism: There are many possible mechanisms that can cause the warming of the Earth, for example: - Natural variation – the climate becomes warmer by internal chaotic dynamics of the earth-atmosphere system (that is, no external influence). - Solar activity – either direct increase of solar energy output or indirect “trigger” mechanisms due to solar activity (though nobody knows how) may cause the surface temperature to go up. 5 - GREENHOUSE EFFECT – increasing quantities of “greenhouse gases” such as CO2, CH4, NO, CFC (carbon dioxide, methane, nitrous oxide, chlorofluorocarbons) etc. The last one is presently thought to be the most likely cause of the global warming and hence we will examine it here. "Greenhouse gases" get their name because they trap radiant energy from the sun that would otherwise be re-radiated back into space, by analogy with the glass panes in a greenhouse. There is a natural greenhouse effect that tempers the earth's climate, and this is not an issue in the debate over global warming. Without it, temperatures would drop by approximately 30°C, the oceans would freeze and life as we know it would be impossible. What climatologists are concerned about, rather, is that increased levels of greenhouse gases in the atmosphere might cause more heat to be trapped. 6 Coal-burning power plants, automobile exhausts, factory smokestacks, and other sources of the human environment contribute about 22 billion tons of carbon dioxide and other greenhouse gases into the earth's atmosphere each year. The atmospheric concentration of CO2 has increased by 31% above pre-industrial levels since 1750. This is considerably higher than at any time during the last 420,000 years, the period for which reliable data has been extracted from ice cores. About three-quarters of the anthropogenic emissions of CO2 to the atmosphere during the past 20 years are due to fossil fuel burning. 7 8 The rest is predominantly due to land-use change, especially deforestation. 9 10 11-Emissions of GHG by Sector 12-Individual GHG Emiss...