教师上课笔记超详解

Unit 8

Unit 8 Focus on Global Warming

Section One Pre-reading Activities

Cultural information

1. Global warming

Global warming is the increase in the average temperature of Earth‗s near-surface air and oceans since the mid-20th century and its projected continuation. Most of the observed temperature increase since the middle of the 20th century was caused by increasing concentrations of greenhouse gases, which results from human activity such as fossil fuel burning and deforestation.

An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, probably including expansion of subtropical deserts. Warming is expected to be strongest in the Arctic and would be associated with continuing retreat of glaciers, permafrost and sea ice. Other likely effects include changes in the frequency and intensity of extreme weather events, species extinctions, and changes in agricultural yields.

Section Two Global Reading

I Text analysis

1.From which perspectives does the text address the issue of global warming?

The text addresses the issue from three perspectives — the general public concern, its causes and consequences, and practical actions to tackle the problem.

2.What‘s the author‘s purpose of writing?

To raise people‘s consciousness of the potential dangers of global warming, and to suggest some actions to combat it.

II Structural analysis

2. Figure out the sub-ideas in the second part.

1) the causes of the rising concentration of greenhouse gases in the atmosphere (Paragraphs 3 and

4)

2) the effect of such concentration on climate change (Paragraphs 5 and 6)

3) the potential threat of global warming to human health and survival (Paragraph 7)

Section Three Detailed Reading

1

教师上课笔记超详解

Unit 8

Text I

Focus on Global Warming

John Weier

1Twenty-five years ago if you made a trip to the local library and perused the periodical section for articles on global warming, you’d probably have come up with only a few abstracts from hardcore science journals or maybe a blurb in some esoteric geopolitical magazine. As an Internet search on global warming now attests, the subject has become as rooted in our public consciousness as Madonna2 or microwave cooking.1

2Perhaps all this attention is deserved. With the possible exception of another world war, giant asteroid, or an incurable plague, global warming may be the single largest threat to our planet.2For decades human factories and cars have spewed billions of tons of greenhouse gases into the atmosphere, and the climate has begun to show some signs of warming. Many see this as a harbinger of what is to come.3If we don’t curb our greenhouse gas emissions, then low-lying nations could be awash in seawater, rain and drought patterns across the world could change, hurricanes could become more frequent, and El Ninos could become more intense.

Our Warming Planet

3What has worried many people now is that over the past 250 years humans have been artificially raising the concentration of greenhouse gases in the atmosphere. Our factories, power plants, and cars burn coal and gasoline and spit out a seemingly endless stream of carbon dioxide. We produce millions of pounds of methane by allowing our trash to decompose in landfills and by breeding large herds of methane-belching cattle.

Nitrogen-based fertilizers, which we use on nearly all our crops, release unnatural amounts of nitrogen oxide into the atmosphere.

4Once these carbon-based greenhouse gases get into the atmosphere, they stay there for decades or longer. According to the Intergovernmental Panel on Climate Change (IPCC) since the industrial revolution, carbon dioxide levels have increased 31 percent and methane levels have increased 151 percent. Paleoclimate readings taken from fossil records show that these gases, two of the most abundant greenhouse gases, are at their highest levels in the past 420,000 years. Many scientists fear that the increased concentrations of greenhouse gases have prevented additional thermal radiation from leaving the Earth. In essence, these gases are trapping excess heat in the Earth’s atmosphere in much the same way that a windshield traps solar energy that enters a car.4

5Much of the available climate data appear to back these fears.5Temperature data gathered from many different sources all across the globe show that the surface temperature of the Earth, which includes the lower atmosphere and the surface of the ocean, has risen dramatically over several decades. Worldwide measurements of sea level show a rise of 0.1 to 0.2 meters over the last century. That’s an increase of roughly 1℃every 4,000 years. Readings gathered from glaciers reveal a steady recession of the world’s continental glaciers. Taken together, all of these data suggest that over the last century the planet has experienced the largest increase in surface temperature in 1,000 years.

2

教师上课笔记超详解

Unit 8

6Not surprisingly, many scientists speculate that such changes in the climate will probably result in hotter days and fewer cool days.6According to the IPCC, land surface areas will increase in temperature over the summer months much more than the ocean.

The mid-latitude to high-latitude regions in the Northern Hemisphere — areas such as the Continental United States, Canada, and Siberia — will likely warm the most. These regions could exceed mean global warming by as much as 40 percent.

7As far as human health is concerned, those hit hardest will probably be residents of poorer countries that do not have the funds to fend against changes in climate.7 A slight increase in heat and rain in equatorial regions would likel …… 此处隐藏：26464字，全部文档内容请下载后查看。喜欢就下载吧 ……