2. © Oxford University Press 2009 Part 7 Global warming─Are humans responsible? Quit 7Global warming – Are humans responsible?

3. © Oxford University Press 2009 Part 7 Global warming─Are humans responsible? Quit 7.1 Is our earth getting warmer?

4. © Oxford University Press 2009 Part 7 Global warming─Are humans responsible? Quit

5. © Oxford University Press 2009 Part 7 Global warming─Are humans responsible? Quit What is the whole world concerned? What issue does the newspaper headlines focus on? Various news headlines at different places in the world

6. © Oxford University Press 2009 Part 7 Global warming─Are humans responsible? Quit What is the whole world concerned? Note: 0°C is the average temperature from 1961 to 1990 Change in global average temperature from 1850 to 2006 Source: IPCC (2007), Fourth Assessment Report The world is getting warmer The global average temperature has increased by 0.74°C since 1850 for the entire planet

7. © Oxford University Press 2009 Part 7 Global warming─Are humans responsible? Quit What is the whole world concerned? The global average temperature increases. This phenomenon is called ______________. global warming Are there any other evidence that supports global warming? Cold nights Cold days The number of cold nights and days are both ( decreasing / increasing ). Note: 0 is the defined value from 1960 to 1990 Source: IPCC (2007), Fourth Assessment Report

8. © Oxford University Press 2009 Part 7 Global warming─Are humans responsible? Quit What is the whole world concerned? The global average temperature increases. This phenomenon is called ______________. global warming Changes in sea ice cover in the Northern Hemisphere since 1900 Source: Hadley Centre for Climate Prediction and Research, the Met Office of the United Kingdom The extent of sea ice cover is ( shrinking / increasing ).

9. © Oxford University Press 2009 Part 7 Global warming─Are humans responsible? Quit Is global warming fact or fiction? Some people argue that global warming issue is only a fiction. Note: 0°C is the average temperature from 1961 to 1990 Global average temperature from 160,000 years to present Source: Hadley Centre for Climate Prediction and Research, the Met Office of the United Kingdom The present air temperature is still lower than the peak 130,000 years ago. The rise of air temperatures in the past 30 years could just be part of a long-term fluctuation.

10. © Oxford University Press 2009 Part 7 Global warming─Are humans responsible? Quit Is global warming fact or fiction? Some people still doubt global warming since fairly accurate data on air temperatures goes back only about 100 years. With only limited climatic data in the old days, it is difficult to ascertain whether the recent rise in air temperatures is not part of a ‘normal’ temperature fluctuation.

11. © Oxford University Press 2009 Part 7 Global warming─Are humans responsible? Quit Is global warming fact or fiction? A melting iceberg in Jökulsárlón, Iceland (Credit: Ng Kim Hung) Nevertheless, after working for years, the scientists in the IPCC have come to the conclusion that global warming is occurring and is a major threat to life on the planet

12. © Oxford University Press 2009 Part 7 Global warming─Are humans responsible? Quit Is global warming a natural phenomenon or an ‘abnormal trend’? Can human activity intensify such an increasing trend in air temperature? Will our planet be destroyed? What can we do to alleviate the problem?

13. © Oxford University Press 2009 Part 7 Global warming─Are humans responsible? Quit