题目内容
Nobody can live around the new lake because ______.
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A Delicate Balance
In 1965 the American statesman Adlai E Stevenson said, "We all travel together, passengers on a little spaceship, dependent on its vulnerable supplies of air and soil. We manage to survive by the care, work, and love we give our fragile craft." Our planet is indeed fragile. Every living thing on this planet is part of a complicated web of life, for no organism lives entirely on its own. Every organism is affected by all that surrounds it whether living or nonliving. And in turn each organism has some effect on its surroundings.
Even the most elementary understanding of ecology requires knowledge of this cause/effect relationship all organisms have on each other. Every thing we do to our environment will in one way or another affect the quality of life we experience on this tiny spaceship. If we want the quality of life to be high, we must be more aware that nature is a finely balanced mechanism and that it will not tolerate the abuse we have been giving it. Consider the following examples of human ignorance concerning the delicate balance of nature.
Aswan and Other Fables
"Once there was a country that desperately needed food and energy for its growing population. It happened that one of the most magnificent rivers in the world flowed through this country. Each year the river deposited tons of mineral-rich silt on its fertile flood plain before it reached the sea. "Why not dam the river," said the country's leaders, "and use the water to irrigate more land, control the annual spring flooding of the river, and provide hydroelectric power all at the same time？" The result of this modern-day fairy tale is known as the billion- dollar Aswan High Dam of Egypt, and not all Egyptians are living happily ever after.
"For one thing, as water backed up behind the dam, almost 100,000 Egyptians had to choose between giving up their family homes and being submerged along with ancient and priceless temples that were part of Egypt's cultural heritage. But there have been far more devastating results. Now that the Nile River floodplain is deprived of its annual enrichment with silt, artificial fertilizer has to be trucked in at a cost of 100 million dollars a year — a cost carried by the subsistence farmers who make, on the average, less than a hundred dollars a year each. Furthermore, now there is nothing to wash away the previous year's silt buildup in the soil. And with silt deposits no longer compensating for erosion, the fertile river delta is shrinking — and an alarming part of what remains has completely dried up. Restoring the delta with pumps, drains, and wells may cost more than the dam itself."
"Ironically, evaporation as well as bottom seepage from the new lake filling in behind the dam is so great that the lake basin may never fill up to predicted levels. So nobody can live around the lake because nobody knows for sure where the shoreline will be. More seriously, there is less water to go around than there was before. And even though some 700,000 new acres (about 1.6 million hectares) have been opened up for agriculture, the population outgrew the potential food increase even before the dam was finished. At the same time, with the nutrient-rich flow of the Nile turned off, another major food source-the sardines, shrimp, and mackerel that flourished in the enriched waters off the delta — has declined catastrophically. Worse yet, the lake and the irrigation networks have so accelerated the spread of blood flukes that half the Egyptian populace are now carriers of schistosomiasis (血吸虫病). In irrigated areas, where eight out of ten humans live, women can expect to live only to age twenty-seven, men to age twenty-five."
The Hawaiian Goose
Another clear example of human ignorance of nature's delicate balance is seen in the near extinction of the Hawaiian Goose or Nene. It was estimated in the late eighteenth cent
【C14】______
The leaders of Egypt decided to dam the Nile for the following purposes except ______.
Every year, the American Lung Association (ALA) releases its annual report card on smog, and every year it gives an "F" to over half the nation's counties and cities. When ALA's "State of the Air 2002" recently came out, dozens of credulous local journalists once again took the bait, ominously reporting that their corner of the nation received a failing grade. The national coverage was no better, repeating as fact ALA's statement that it is "gravely concerned" about air quality, and neglecting to solicit the views of even one scientist with a differing view. Too bad, because this report card says a lot less about actual air quality than it does about the tactics and motives of the ALA.
The very fact that 60 percent of counties were giver an "F" seems to be alarmist. This is particularly tree given that smog levels have been trending downward for several decades. According to the Environmental Protection Agency (EPA) statistics, ozone, the primary constituent of smog, progress will likely continue, even without the wave of new regulations ALA is now demanding.
ALA is correct that some areas still occasionally exceed the federal standard for ozone, but such spikes are far less frequent than in the past. Even Los Angeles, the undisputed smog capital of America, has cleaned up its act considerably. Los Angeles, which exceeded federal smog standards for 154 days in 1989, has had 75 percent fewer such spikes in recent years. But an ALA-assigned "F" misleadingly implies that air quality has not improved at all.
Most of the nation is currently in attainment with the current smog standard, and much of the rest is getting close. Nonetheless, ALA chose to assign an "F" to entire county based on just a few readings above a strict new EPA standard enacted in 1997 but not yet in force. In effect, ALA demanded a standard even more stringent than the federal government's, which allows some leeway for a few anomalously high readings in otherwise clean areas. ALA further exaggerated the public-health hazard by grossly over stating the risks of these relatively minor and sporadic increases above the standard.
The media's response to ALA's "State of the Air 2002" can best be described as ______.
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