book2Unit4_Weather_and_Climate泛读.ppt

Overview Text 1 What Makes the Weather? Text 2 Types of Climate Teaching objectives 1. To help students to understand some basic reading terms such as: topic, main idea, supporting details etc. 2. To teach students how to find the main idea in different reading materials. 3. To help students learn to use some useful expressions in this unit. Part I Pre-reading task Text A  What Makes the Weather Reading Skill: Finding the Main Idea p48 The topic being discussed in the short passage above is Clouds’ influence on temperature 2. The writer’s main idea is Clouds can greatly affect the temperature of the earth’s surface 3. The specific details are 3 points Text I What makes the weather? Word pretest: D A A B A C A B D C Lead-in Questions of the Unit Question 1. What is the difference between weather and climate? Question 2. What do you think are the causes of global warming? Global Warming The Intergovernmental Panel on Climate Change (IPCC) concludes that most of the observed temperature increase since the middle of the 20th century was very likely caused by increasing concentrations of greenhouse gases resulting from human activity such as fossil fuel burning and deforestation. The IPCC also concludes that variations in natural phenomena such as solar radiation and volcanic eruptions火山喷发 had a small cooling effect after 1950.These basic conclusions have been endorsed赞成 by more than 40 scientific societies and academies of science, including all of the national academies of science of the major industrialized countries. An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, probably including expansion of subtropical deserts. Warming is expected to be strongest in the Arctic and would be associated with continuing retreat of glaciers, permafrost永冻土 and sea ice. Other likely effects include changes in the frequency and intensity of extreme weather events, species extinctions, and