Global Warming. For 2.5 million years, the earth's climate has fluctuated, cycling from ice ages to warmer

Transcription

1 Global Warming For 2.5 million years, the earth's climate has fluctuated, cycling from ice ages to warmer periods. But in the last century, the planet's temperature has risen unusually fast, about 1.2 to 1.4 degrees Fahrenheit. Scientists believe it's human activity that's driving the temperatures up, a process known as global warming. Ever since the industrial revolution began, factories, power plants and eventually cars have burnt fossil fuels such as oil and coal, releasing huge amounts of carbon dioxide and other gases into the atmosphere. These greenhouse gases trap heat near the earth through a naturally-occuring process called the greenhouse effect. The greenhouse effect begins with the sun and the energy it radiates to the earth. The earth and the atmosphere absorb some of this energy while the rest is radiated back into space. Naturallyoccuring gases in the atmosphere trap some of this energy and reflect it back, warming the earth. Scientists now believe that the greenhouse effect is being intensified by the extra greenhouse gases that humans have released. Evidence for global warming includes a recent string of very warm years. Scientists report that 1998 was the warmest year in measured history with 2005 coming in second. Meanwhile, readings taken from ice core show that the greenhouse gases carbon dioxide and methane have hit their highest levels in the past 420,000 years. Arctic sea ice is also shrinking. According to NASA studies, the extent of arctic sea ice has declined about 10% in the last thirty years. As long as industrialised nations consume energy and developping countries increase their fossil fuel consumption, the concentration of greenhouse gases in the atmosphere will continue to rise. Researchers predict that temperatures will increase about 2 f to 10 f by the end of the 21 st century. What's less certain is what rising temperatures mean for the planet. Some climate models predict subtle changes, others forecast rising sea levels which could flood coastal areas around the world.weather patterns could change, making hurricanes more frequent. Severe droughts could become more common in warm areas, and species unable to adapt to the changing conditions would face extinction. Although much remains to be learnt about global warming, many organisations advocate cutting greenhouse gas emissions to reduce the impact of global warming. Consumers can help by saving energy around the house, switching to compact fluorescent light bulbs and driving fewer miles in the car each week. These simple changes may help keep the earth cooler in the future. National Geographic video,

2 Global Warming National Geographic video, 2008 WORKSHEET I. Vocabulary A. Scan the text for words or expressions related to global warming. Underline them. B. Now classify these words and expressions below in the left column. Give either their French equivalent or their definition in the right column, as well as an example in a sentence taken from the text or the dictionary

3 II. Present perfect Les phrases suivantes ont été extraites du script de la vidéo. 1. Donner une traduction pour chacune d'entre elles. 2. Expliquer l'utilisation des temps en anglais & justifier l'emploi de for et since. (A-Z ) 1.For 2.5 million years, the earth's climate has fluctuated. 2. But in the last century, the planet's temperature has risen unusually fast. 3.Ever since the industrial revolution began, factories, power plants and eventually cars have burnt fossil fuels such as oil and coal. 4. According to NASA studies, the extent of arctic sea ice has declined about 10% in the last thirty years. 5. Scientists report that 1998 was the warmest year in history. 6.Readings from ice core show that the greenhouse gases carbon dioxide and methane have hit their highest levels in the past 420,000 years. 7.Scientists now believe that the greenhouse effect is being intensified by the extra greenhouse gases that humans have released....

4 III. Graph description 1. How would you translate «to increase» and «to decrease» into French? Find synonyms for these two words in the text and in your vocabulary : to increase =... to decrease =... Find in the text the word you would use to describe a series of increases and decreases :... 2.Complete the graph with the right verbs from the list, following the example : to rise, to fall, to level off, to fluctuate, to go up, to stabilize, to plummet, to rocket, to hit (its) highest levels, to reach a peak, to soar, to go down, to increase, to decrease, to decline. 16 CO2 in Grenoble, tons/year to go up 3. You can use adverbs with those verbs to describe the trend in more details: regularly slightly = a little, slowly dramatically, sharply = a lot gradually, steadily = Use those adverbs with a verb to complete the vocabulary. Ex : to plummet = to decrease dramatically There are also a few nouns to describe trends : an increase a decrease a rise a fall

5 Pay attention to prepositions : to level off/stabilize at 3 tons/year. to reach a peak of 15 tons/year. 3. Use this new vocabulary to describe the graph above (III.2) Now describe and analyse the following graph. Pay attention to units and scales!

6 IV. Modal auxiliaries expressing probability 1. a. Read the text again and highlight modal auxiliaries. b. Translate the sentences where these modal auxiliaries appear. c. What do these modal auxiliaries express? 2. Modal auxiliaries can express present or future probability. Ex : Where's Brian? He may be in the kitchen. (present) It may snow tomorrow. (future) You can see in this example that modal auxiliaries do not always show whether the situation is in the present or in the future. Only the context will show that. Classify the following modal auxiliaries on the probability scale (MAY, CAN T, MIGHT, SHOULD, WILL, MUST, COULD) 100% 90% 75% 50% 25% 0-10% Warning! A modal auxiliary is always and only followed by a verb : MOD + BV! Ex : Sea level will rise. I can swim. Sea level will rising. I can to swim. 2. Now make a few sentences using different modal auxiliaries to answer the following questions : What may happen if we do not tackle global warming quickly? The sea level will rise