global warming,全球变暖英文演讲,大学英语演讲.ppt

1、张莉 Zhang Li 2012011678,global warming,content,We can do,Effect,Definition,Cause,Definition,what is global warming?,Global warming is the observed and projected increases in the average temperature of Earths atmosphere and oceans.,present situation,The Earths average temperature rose about 0.6 Celsiu

2、s (1.1 Fahrenheit) in the 20th century,prediction,According to different assumption about the future behaviour of mankind, a projection of current trends as represented by a number of different scenarios gives temperature increases of about 3 to 5 C (5 to 9 Fahrenheit) by the year 2100 or soon after

3、wards.,Global Warming Causes: A Top 5 List,Carbon dioxide emissions from fossil fuel burning power plants,Carbon dioxide emissions from burning gasoline for transportation,Deforestation, especially tropical forests for wood pulp ,and farmland,Increase in usage of chemical fertilizers on croplands,Me

4、thane emissions from animals , agriculture such as rice paddies, and from Arctic seabeds,Carbon dioxide emissions from fossil fuel burning power plants,Every day, more electric gadgets flood the market, and without widespread alternative energy sources, we are highly dependent on burning coal for ou

5、r personal and commercial electrical supply.,Carbon dioxide emissions from burning gasoline for transportation,With our population growing at an alarming rate, the demand for more cars and consumer goods means that we are increasing the use of fossil fuels for transportation and manufacturing .Our c

6、onsumption is outpacing our discoveries of ways to mitigate the effects.,Methane emissions from animals , agriculture such as rice paddies, and from Arctic seabeds,Methane is another extremely potent greenhouse gas, ranking right behind CO2.When organic matter is broken down by bacteria under oxygen

7、-starved conditions as in rice paddies, methane is produced .,Deforestation , especially tropical forests for wood, pulp, and farmland,The use of forests for fuel is one cause of deforestation. Forests remove and store carbon dioxide from the atmosphere, and this deforestation releases large amounts

8、 of carbon, as well as reducing the amount of carbon capture on the planet.,Increase in usage of chemical fertilizers on croplands,In the last half of the 20th century, the use of chemical fertilzers has risen dramatically. The high rate of application of nitrogen-rich fertilizers has effects on the

9、 heat storage of cropland and the run-off of excess fertilizers creates dead-zones in our oceans.,Rise in sea levels worldwide,More killer storms,Massive crop failures,Widespread extinction of species,Disappearance of coral reefs,Global Warming Effects: A Top 5 List,in sea levels worldwide,Scientist

10、s predict an increase in sea levels worldwide due to the melting of two massive ice sheets in Antarctica and Greenland, especially on the East coast of the US. However, many nations around the world will experience the effects of rising sea , which could displace millions of people.,More killer stor

11、ms,The maximum wind speeds of the strongest tropical cyclones have increased significantly since 1981, according to research published in Nature this week. And the upward trend, thought to be driven by rising ocean temperatures, is unlikely to stop at any time soon.,Massive crop failures,“Climate ch

12、ange is expected to have the most severe impact on water supplies”. “Shortages in future are likely to threaten food production, reduce sanitation, hinder economic development and damage ecosystems. It causes more violent swings between floods and droughts.”,Widespread extinction of species,Accordin

13、g to research published in Nature , by 2050, rising temperatures could lead to the extinction of more than a million species . And because we cant exist without a diverse population of species on Earth, this is scary news for humans.,Disappearance of coral reefs,A report on coral reefs from WWF says

14、 that in a worst case scenario, coral populations will collapse by 2100 due to increased temperatures and ocean acidification . The bleaching of corals from small but prolonged rises in sea temperature is a severe danger for ocean ecosystems, and many other species in the oceans rely on coral reefs

15、for their survival.,Top 6 Things You Can Do,Top 6 Things You Can Do,Buy minimally packaged goods,Use recycled paper,Unplug unused electronics,Use public transportation,Use compact fluorescent bulbs,Choose vegetarian or vegan meals,Use recycled paper,Make the most of scrap paper for shopping lists, n

16、otes ,scrapbooks , telephone ,messages, taking notes in class, etc. Recycle your paper only when it has been thoroughly used up!,Buy minimally packaged goods,Less packaging could reduce your garbage significantly, saving 1,200 pounds of carbon dioxide and $1,000 per year. Reduced packaging is not on

17、ly a good idea but also very achievable,Unplug unused electronics,Save over 1,000 lbs of carbon dioxide and US$256 per year by unplugging them or switching them off at the wall using a power surge-protector Get into the habit of switching the power off before you go to bed.,Use public transportation

18、,Taking the bus, the train, the subway or other forms of public transportation lessens the load on the roads and reduces ones individual greenhouse gas emissions by an average of 1600 pounds per year.,Choose vegetarian /vegan meals,Choosing vegetarian foods drastically reduces agricultural water consumption and land use, and favorably impacts biodiversity. Vegetarian diets have been shown to promote good health.,Thanks for your attention,The End,张莉 Zhang Li 2012011678,