Luyện Nghe VOA: Good News: Earth's Ozone Hole is Healing

Good News: Earth's Ozone Hole is Healing



There is big news about the environment: Scientists say a hole in Earth’s (1)_________________ layer is starting to heal.
A new study confirms the hole is (2)_______________. A report on the study was published late last month in the journal Science.
The scientists say the reason for the (3)_________________ in the release of man-made chemicals into (4)________________. These chemicals are called chlorofluorocarbons or CFCs for short.
“It’s (5)_______________,” said Susan Solomon, the lead writer of the report. “I didn’t think it would be this early,” she said.
Solomon is an (6)__________________ and works at the Massachusetts Institute of Technology.
Ozone is a form of oxygen gas. It is found in the air we breathe and in the (7)_________________. Near Earth, ozone in the air is a danger to life. It is a pollutant. But the ozone layer, 10 to 50 kilometers up in the atmosphere, protects life on Earth. It helps to (8)_______________ ultraviolet (UV) waves from the sun. It stops them from reaching the planet’s surface.
Researchers (9)____________________ in the ozone layer over Antarctica more than 30 years ago.
The new report (10) ____________________ hole to a worldwide ban on chlorofluorocarbons.
CFCs once were commonly used in many products, including aerosols, (11)_________________, refrigerators and plastics. Scientists found that when released into the air, the chemicals (12)________________ layer, creating the hole.
CFCs were banned when world leaders (13)________________ called the Montreal Protocol in 1987.
Susan Solomon compared the ozone hole (14)_____________ that needs healing.
“It isn't just that the patient is in (15)____________,'' Solomon said. "He's actually starting to get better. The patient got very sick in the ‘80s when (16)_________________ all that chlorine into the atmosphere.”
Measurements taken in September showed the (17)______________ since the year 2000. The new numbers show that the hole is smaller by 4.5 million square kilometers. That is about half the area of the (18)_____________.
One year was different, however. In 2015, the ozone hole got bigger, not smaller. After looking at (19)_________________, Solomon said that increase resulted from a natural event. She said it was caused by the eruption of the Calbuco volcano in Chile.
While the healing is coming earlier than many (20)_________________, it is an ongoing, continuing process. The ozone hole will not be (21)______________________ for at least another 30 years. Estimates are it will close by around 2050.
"We can now be confident that the things we've done have put the planet on a (22)_________________," Solomon said.
"There is a sense of (23)__________________,''' said Mario Molina in an email to VOA. Molina works at the University of California, San Diego. He shared the 1995 Nobel Prize for Chemistry for his research on the ozone issue. He (24)__________________ this latest study, but was not involved in it.
Not-so good news
However, there is other news about Antarctica that is not as good.
For the first time in four million years, Antarctica (25) ______________ (CO2) levels above the level of 400 parts per million. That information comes from U.S. scientists at the National Oceanic and Atmospheric Administration (NOAA).
“The far southern hemisphere was the last place on earth where CO2 had not yet (26)_______________,” of 400 parts per million (ppm), said Pieter Tans. He is the lead scientist of NOAA's Global Greenhouse Gas Reference Network.
“Global CO2 levels will not return to values below 400 ppm in our lifetimes, and almost certainly for much longer,” he said.
Scientists say too much CO2 (27)__________________ on Earth to rise.
CO2 levels usually go up in (28)__________________. In the warmer months, plants in the northern hemisphere use some of it, and that lowers the levels. But NOAA notes that plants are not enough to (29)________________ of CO2 levels. Those levels have risen every year since 1958, when measurements began.
Tans said that evidence shows that the CO2 increase is caused “(30)_________________ human activities.” These activities include burning oil and other fossil fuels for energy.
Because the burning of (31)_______________ has been at a record high during the last several years, Tans said, the rate of CO2 increase has also been at (32)_________________. He said some of the gas will stay in the atmosphere for thousands of years.
I’m Anne Ball.
And I’m Bryan Lynn.
Smita Nordwall reported this story for VOANews.com. Anne Ball adapted those reports for Learning English. George Grow was the editor.
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Words in This Story

layer – n. amount of something spread over an area
ultraviolet – adj. rays of light that cannot be seen
chlorofluorocarbon – n. an organic compound that damaged the ozone layer
aerosol – n. a substance like hair spray kept in a container under pressure that is released in a fine spray when a button is pushed
confident – adj. a feeling or belief you can do something well
global – adj. involving the entire world
greenhouse gas – n. a gas in the atmosphere that absorbs and emits radiation, causing greenhouse effect and warming of Earth’s temperature

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