全球變暖 (英文)ppt課件

1,What is Global Warming?,Global warming is the observed century-scale rise in the average temperature of Earths climate system. 全球變暖是指全球氣溫在近一百年來不斷上升，呈現(xiàn)變暖的趨勢，這樣一種氣候變化特征。,2,The cause of global warming,1.Natural cause: The green house effect 2.Human reasons: Human activities,3,The green house effect,The greenhouse effect is a process by which thermal radiation from a planetary surface is absorbed by atmospheric greenhouse gases, and is re-radiated in all directions. Since part of this re-radiation is back towards the surface and the lower atmosphere, it results in an elevation of the average surface temperature above what it would be in the absence of the gases. 溫室效應(yīng)是一個過程,從行星表面熱輻射被大氣吸收溫室氣體,并再次輻射向四面八方。因為這部分再輻射回到地表和低層大氣,它導致海拔平均表面溫度高于沒有這部分氣體。,4,5,Human activities,1.Industrial waste gases 2.Deforestation 3.Traffic jam,6,Industrial waste gases,7,Deforestition,8,Traffic jam,9,Whatre the effects of global warming,Negative effects 1.Cause the sea level to rise 2.Melting glaciers 3.Droughts 4.Disappearance of species,10,Positive effects 1.make plants grow faster 2.crops will produce more,Droughts,If the earths average temperature 4 degrees Celsius, the world will have more than 30 million people water shortages. 如果地球平均氣溫上升4攝氏度，全球就會有30多億人面臨缺水問題。,11,Melting glaciers,the earths poles island fate snow melt can lead to rising sea levels, many islands will be drowned, some island may not exist. 地球兩極冰雪融化會導致海平面上升，眾多島嶼將被淹沒，一些島國可能不復存在。,12,So,let us do our best to solve this problem,or we will bear this problem in the future,13,