Globle Warming 全球变暖 英文论文.doc

Globle Warming Speaker : 2012011678 Definition ? What is global warming? Global warming is the observed and projected increases in the average temperature of Earth's atmosphere and oceans. ? Present situation The Earth's average temperature rose about ° Celsius ( ° Fahrenheit) in the 20th century ? Prediction According to different assumption about the future behaviour of mankind, a projection of current trends as represented bya number of different scenarios gives temperature increases of about 3° to5° C (5° to9° Fahrenheit) by the year 2100 or soon afterwards. Causes ? Carbon dioxide emissions from fossil fuel burning power plants Every day, more electric gadgets flood the market, and without widespread alternative energy sources, we are highly dependent on burning coal for our personal mercial electrical supply. Carbon dioxide emissions from burning gasoline for transportation With our population growing at an alarming rate, the demand for more cars and consumer goods means that we are increasing the use of fossil fuels for transportation and manufacturing .Our consumption is outpacing our discoveries of ways to mitigate the effects. ? Methane emissions from animals , agriculture such as rice paddies, and from Arctic seabeds Methane is another extremely potent greenhouse gas, ranking right behind matter is broken down by bacteria under oxygen-starved conditio