image- Ozone balloon

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What chemical is a major cause of ozone destruction?

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How did scientists measure the loss of ozone at high altitudes?

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Why was discovering the thinning ozone layer important?

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In May 1985 British scientists reported a steep drop, over several years, of austral springtime ozone in the atmosphere above Halley Station, Antarctica.

The report seemed to confirm dire predictions made a decade before that man-made chemicals (principally chlorofluorocarbons,spaceor CFCs) might destroy protective stratospheric ozone.

Discovering the causes
By November 1985 NSF delivered ozone sensors, along with balloons and helium,spaceto researchers at McMurdo and Amundsen-Scott South Pole stations so they could measure the loss of ozone as a function of altitude.

Then NSF, the National Oceanic and Atmospheric Administration (NOAA) and the National Aeronautics and Space Administration (NASA) rapidly put together a comprehensive research team to discover the depletion’s cause.

The team, arriving at McMurdo in late August 1986, established beyond doubt that the chemistry of the stratosphere above McMurdo was grossly abnormal and levels of key chlorine compounds were greatly elevated. In just two months this group learned most of what we know about the ozone hole.

The next year NSF, NASA, NOAA and international partners conducted an all-out assault on the problem, returning to McMurdo and flying instrumented airplanes from Punta Arenas, Chile.

Predictions confirmed
The results strengthened and confirmed the previous year’s work. While this campaign was still going on, international negotiators meeting in Canada produced the "Montreal Protocol," which phased out production of CFCs in industrialized countries.

This treaty was the first to address the Earth's environment, and it changed forever a multibillion-dollar industry.The ozone hole was the first definitive demonstration that humans are capable of affecting the entire global system.


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