globalwarming,全球變暖英文演講,大學(xué)英語演講

1、張莉Zhang Li2012011678contentWe can do Effect DefinitionCauseDefinitionwhat is global warming? Global warming is the observed and projected increases in the average temperature of Earths atmosphere and oceans.present situationThe Earths average temperature rose about 0.6 Celsius (1.1 Fahrenheit) in th

2、e 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 scenariosgives temperature increases of about 3 to 5C (5to 9Fahrenheit) by the year 2100 or soon afterwards. Global Warming Causes

3、: A Top 5 ListCarbon dioxide emissions from fossil fuel burning power plantsCarbon dioxide emissions from burning gasoline for transportationDeforestation, especially tropical forests for wood pulp ,and farmlandIncrease in usage of chemical fertilizers on croplandsMethane emissions from animals, agr

4、iculture such as rice paddies, and from Arctic seabedsCarbon dioxide emissions from fossil fuel burning power plantsEvery day, more electric gadgets flood the market, and without widespread alternative energy sources, we are highly dependent on burning coal for our personal and commercial electrical

5、 supply.Carbon dioxide emissions from burning gasoline for transportationWith 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 consumption is outpacing our discoverie

6、s of ways to mitigate the effects.Methane emissions from animals, agriculture such as rice paddies, and from Arctic seabedsMethane is another extremely potent greenhouse gas, ranking right behind CO2.When organic matter is broken down by bacteria under oxygen-starved conditions as in rice paddies, m

7、ethane is produced . Deforestation, especially tropical forests for wood, pulp, and farmlandThe 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 of carbon, as well as reducing the amount o

8、f carbon capture on the planet.Increase in usage of chemical fertilizers on croplandsIn the last half of the 20th century, the use ofchemical fertilzershas risen dramatically.The high rate of application of nitrogen-rich fertilizers has effects on the heat storage of cropland and the run-off of exce

9、ss fertilizers createsdead-zonesin our oceans.Risein sea levels worldwide More killer storms Massive crop failures Widespread extinction of speciesDisappearance of coral reefsGlobal Warming Effects: A Top 5 Listin sea levelsworldwide Scientists predict an increase in sea levels worldwide due to the

10、melting of two massive ice sheets in Antarctica and Greenland, especially on theEast 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 storms The maximum wind speeds of the strongest tropical cyclone

11、s 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 change is expected to have the most severe impact on water supp

12、lies”.“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 According to research published in Nature , by 2050, rising temperatures

13、 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 that in a worst case scenario, coral populations will collapse

14、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 for their survival. Top 6 Things You Can Do Top 6 Things You Can

15、 Do Buy minimally packaged goods Use recycled paperUnplug unused electronics Use public transportation Use compact fluorescent bulbs Choosevegetarianorveganmeals Use recycled paper Make the most of scrap paper forshopping lists, notes ,scrapbooks ,telephone ,messages,taking notes in class, etc. Recy

16、cle 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 only a good idea but also very achievable Unplug unused electronics Save ov

17、er 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 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 b