Unit4_Global_warming课件40新人教版选修6）.ppt

;Unit4 Global Warming Reading The Earth Is Becoming Warmer – But Does It Matter?; ;Sophie Armstrong;Graph 1 shows the temperature increases___________________ between _____________________.; How has the global warming come about? ;;Why do greenhouse gases cause the increasing temperature? They trap_____ from the sun and therefore warm _________. This process is called ________________________; ② Greenhouse effect--- greenhouse gases--- we need those gases. ;③ We add huge quantities of extra carbon dioxide to the atmosphere by burning Fossil fuels. ;Graph 2 shows the carbon dioxide content in the atmosphere from 1957 to 1997 went up from__________________ to _________________.;Part 3: different attitudes towards the effects of global warming;Part 3: two different attitudes towards the effects of global warming;; But the attitudes of scientists towards this rise are completely _________. Greenhouses gases continue to _______ in the atmosphere. Even if we start reducing the amount of carbon dioxide and other gree -nhouse gases, the climate is going to keep on ______ for decades or centuries. No one knows the ______of global warming. Does that mean we should do________? Or, are the risks too great? ;;.;×;Return the green world to us