Unit4_Global_warming课件39新人教版选修6）.ppt

;;Traffic Jam ; 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 Earth’s average temperature would be about 60oF colder. Because of how they warm our world, these gases are referred to as greenhouse gases. ;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 .; 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. ;;What will you do every day to help reduce greenhouse gases?;And Taking train can also help a reduction of greenhouse gas. ;The recycling symbol ;;Paper recycling ;using low-flow shower heads;film;Thank you for your listening!