Unit 4 Global Warming,Warming Up and Reading,Extreme heat 酷暑,Can you think of some natural disasters (自然灾害) because of the extreme heat?,drought(旱灾),fire,flood,hurricane /typhoon,I feel hot !,.,Low-carbon life （低碳生活）,The Earth is Becoming Warmer -But Does It Matter? 地球在变暖 要不要紧？,Reading,New Words and expressions,temperature 温度 one degree Fahrenheit 华氏一度 explore 探索 human activities 人类活动 phenomenon 现象 subscribe to 同意，赞成 fossil fuels 矿物燃料 byproduct 副产品 “greenhouse” gases 温室气体 atmosphere 大气 methane 甲烷， 沼气,degree Celsius 摄氏度 quantities of 大量的 accurate measurements 精确的测量 data 资料，数据 catastrophe 大灾难 be opposed to 反对 environmental consequences 环境影响 a great range of 大量的 even if 即使 keep on 继续,Scanning,Who ：_ Three scientists: _ _,Sophie Armstrong,Dr Janice Foster;,Charles Keeling;,George Hambley;,What are the two graphs about?,Graph 1 shows the temperature difference (温度差异) from 1860 to 2000.,Graph 2 shows the carbon dioxide content(二氧化碳含量) in the atmosphere from 1957 to 1997.,Graph 1:,Graph 2:,Careful Reading,Paragraph 1,Paragraphs 2&5,Paragraph 6,Main idea of the text,Paragraph 7,How global warming comes about? (全球变暖是怎样产生的),Two different opinions about global warming.,The earth is becoming warmer.,Should we do anything?,During the 20th century, the temperature of the earth didnt seem to increase much. 2. There is no doubt that global warming is caused by the human activities. 3. Not all scientists believe that the increase in the earths temperature is due to the burning of fossil fuels.,True or false,4. The levels of carbon dioxide have increased greatly over the last 100150 years. 5. George Hambley believes that global warming will do good to the earth. 6. We know the effects of global warming.,How has global warming come about(产生)?,1. Human activity,The problem begins when huge quantities of extra carbon dioxide (大量的二氧化碳) are added into the atmosphere.,is due to the burning of fossil fuels,2. Greenhouse gases,Paragraph 2&3,Fossil Fuel(矿物燃料),coal,oil,gas, ,produce,二氧化碳,Have you ever seen a greenhouse?,Methanemi:ein,What are Greenhouse gases?,There are gases called “greenhouse gases”, including,Carbon dioxide,Water vapor,They trap the heat from the sun and warm the earth.,Dr.Foster:_ George Hambley:_,What do the scientists think about global warming? Do they agree with one another?,It would be a catastrophe.,we should not worry about it.,They have quite different attitudes towards this issue.,Paragraph 6,Does global warming matter?,Positive effects （正面影响）,Negative effects (负面影响）,cause the sea level to rise severe storms floods droughts famines the spread of diseases disappearance of species,Positive effects,Negative effects,tsunami,The sea level to rise.,tornados,Severe storms,droughts,famines,the spread of diseases,destruction of species,cause the sea level to rise severe storms floods droughts famines the spread of diseases disappearance of species,Positive effects,Negative effects,make plants grow quicker crops will produce more a greater range of animals make life better,Summary,How,Effects,1. Human activities,2.Greenhouse gases,Carbon dioxide,cause the sea level to rise severe storms floods droughts famines the spread of diseases disappearance of species,Positive effects,Negative effects,make plants grow quicker crops will produce more a greater range of animals make life better,Homework,1.Read the text again, and try to retell it. 2.Find out the difficult sentences in the passage .,Thank You,