Global Dimming
There are evidences showing that each year less light reaches the surface of the
Earth, which in other words means that it is almost time to wave sunshine goodbye.
Global dimming, also known as solar dimming, refers to the transmission of sunlight
through the atmosphere is decreasing. Scientists now agree that as cloud cover and
particles in the atmosphere increase, the amount of radiation reaching us from the Sun is
falling. So far, through the sunlight measurements we see that the amount of energy from
the sun---- solar radiation---- is shrinking by about 3 percent per decade.
Continuing to consume vast amounts of energy such as the engine in your car and
the power station supplying electricity to your home, you might not know that burning of
fossil fuels such as oil and coal is actually creating two effects. One of them is global
warming, which, as you know, is caused by greenhouse gases and the other is global
dimming, which is caused by by-products which are also pollutants, such as sulphur
dioxide, soot, and ash. In global warming, gases in the atmosphere, such as carbon
dioxide, trap some of the sun's heat and keep it from radiation back out to space, thereby
raising the Earth's temperature. While global dimming, by shielding the oceans from the
full power of the Sun, may be disrupting the pattern of the world's rainfall. We can tell
that as evaporation rates are speedily falling. Less evaporation there is, less rainfall we
have. Roughly speaking, global warming leads to rising sea levels and unusual climate
changes, while global dimming leads to drought and something worse---underestimations of scientists for the true power of the greenhouse effect.
It now appears the warming from greenhouse gases has been offset by a strong
cooling effect from dimming--- in effect two of our pollutants have been cancelling each
other out. Does it mean that the effect is to protect us from global warming?
Paradoxically, with a deeper look at this, however, it shows that unfortunately this is not
the case. Due to the pollutants that lead to global dimming also lead to various human
and environmental problems, such as smog, respiratory problems and acid rain, in Europe,
various measures have been taken in recent years to reduce the dimming emission
without reducing the greenhouse gas emission in parallel. This has already left a few
effects leading many scientists to conclude that the present-day climate is less sensitive to
the effects of carbon dioxide than it was.
So, that is to say, global dimming is merely cushioning us from the full impact of
global warming. We have to take prompt action to combat both at the same time or our
climate will be radically altered, rendering many of the planet uninhabitable. Trust me,
I'm not telling you something alarming. We must change our way of life to curb our
emissions of greenhouse gases by developing alternative energy such as fuel cells and the
solar power, leaving no pollution to the planet at all costs. With all our efforts to deal with
the issue, we may not only be able to enjoy sunbaths instead of saying goodbye to
sunshine but also have a brighter day tomorrow.
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) 1. Global dimming is
.
(A) because the sun is dying
(B) due to the particles in the air blocking the sunlight
(C) the result of global warming
(D) due to unusual climate changes
) 2. Which of the following is true?
(A) Global dimming is not so devastating as global warming.
(B) Global dimming is caused by carbon dioxide.
(C) Global dimming has nothing to do with global warming.
(D) Both global dimming and global warming are the by-products of modern
industrialization.
(
(
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) 3. What does global dimming do to the Earth?
(A) It rises sea levels.
(B) It causes less rainfall.
(C) It causes unusual climate changes.
(D) It saves us from global warming.
) 4. Which is the least possible meaning of the word “cushion?”
(A) soften (B) moderate (C) relax (D) save
) 5. What can we do about global dimming?
(A) Take action to deal with global warming as well as global dimming.
(B) Take more sunbaths.
(C) Stop using natural resources.
(D) Take global warming more seriously.