全球气候变暖unit1GlobalWarming.ppt

,Unit 1,Global Warming,What are the causes of global warming?,Traffic Jam,Factory,The greenhouse effect is the rise in temperature that the Earth experiences because certain gases in the atmosphere (water vapor(水蒸汽) , carbon dioxide, nitrous oxide(一氧化二氮), and methane(甲烷), for example) trap energy from the sun. Without these gases, heat would escape back into space and Earths average temperature would be about 60F colder. Because of how they warm our world, these gases are referred to as greenhouse gases.,The Greenhouse Effect,The Greenhouse Effect,Some greenhouse gases occur naturally in the atmosphere, while others result from human activities. Naturally occurring greenhouse gases include water vapor,carbon dioxide, methane(甲烷), nitrous oxide(一氧化二氮), and ozone(臭氧). Certain human activities, however, add to the levels of most of these naturally occurring gases .,What Are Greenhouse Gases?,Owing to the rise in atmospheric carbon dioxide caused by modern industrial societies widespread combustion(燃烧) of fossil fuels (coal, oil, and natural gas), the greenhouse effect on Earth may be intensified and long-term climatic changes may result.,London,USA,Which countries do you think contribute more to global warming?,South Africa,What will you do every day to help reduce greenhouse gases?,Taking public transport like buses can reduce greenhouse gas emissions,And Taking train can also help a reduction of greenhouse gas.,The recycling symbol,Buy the recycled products,Recycled products,Recycling the bottles,Your glass bottles could be recycled into house insulation, plastic bottles could be made into a cozy fleece jacket.,Paper recycling,your paper could become part of a road or race-track,using low-flow shower heads,buying energy-efficient lig