高考英语一轮复习 Unit4 Global warming导学案 新人教版选修6-新人教版高三选修6英语学案

河北省武邑中学 2016 届高考英语一轮复习 Unit4 Global warming 导学案 新人教版选修 6ReadingTHE EARTH IS BECOMING WARMER — BUT DOES IT MATTER?During the 20th century the temperature of the earth rose about one degree Fahrenheit. That probably does not seem much to you or me, but it is a rapid increase when ___1_____(compare) to other natural changes. So how has this come about and does it matter? Earth Care’s Sophie Armstrong explores these questions.There is no doubt that the earth is becoming warmer (see Graph 1) and that it is human activity that has caused this global warming rather than a random but natural phenomenon.All scientists subscribe to the view that the increase in the earth’s temperature is due to the burning of fossil fuels like coal, natural gas and oil to produce energy. Some byproducts of this process are called “greenhouse” gases, the most important one of which is carbon dioxide. Dr Janice Foster explains: “There is a natural phenomenon that scientists call the ‘greenhouse effect’. This is when small amounts of gases in the atmosphere, like carbon dioxide, methane and water vapour, trap heat from the sun and therefore warm the earth. Without the ‘greenhouse effect’, the earth _____2________(be) about thirty-three degrees Celsius cooler than it is. So, we need those gases. The problem begins when we add huge quantities of extra carbon dioxide into the atmosphere. It means that more heat energy tends to be trapped in the atmosphere causing the global temperature to go up.”We know that the levels of carbon dioxide _____3_____(increase) greatly over the last 100 to 150 years. It was a scientist called Charles Keeling, who made accurate measurements of the amount of ca...