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Say goodbye to large ozone holes.

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A new study from NASA scientists

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suggests by the year 2040,

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the Antarctic ozone hole will be permanently smaller 

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than the giant holes of today.

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Since the early 90s,

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observed hole sizes have been larger than 8 million square miles 

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with exact sizes changing each year.

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The ozone hole is a seasonal thinning of the ozone layer over Antarctica.

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The ozone hole size varies in part due to

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levels of ozone-depleting chemicals in the atmosphere.

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Man-made chemicals that destroy ozone 

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are transported from the equator to the poles.

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In the Southern Hemisphere, they are trapped by the winds of the polar vortex, 

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a ring of fast-moving air that circles the South Pole.

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Although levels of these chemicals have been declining since the late 1990s

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due to the Montreal Protocol

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they will remain in the atmosphere for years,

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affecting ozone levels well into the century.

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High in the atmosphere, the chemicals react 

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with sheets of iridescent ice clouds

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which trigger the destruction of ozone.

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In years with warm temperatures,

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fewer ice clouds form, resulting in holes that are smaller.

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In years with cold temperatures,

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more ice clouds form, resulting in holes that are larger.

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But in order to understand how hole sizes will change in the future, 

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scientists needed a more accurate picture 

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of levels of man-made chemicals in the atmosphere.

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Using NASA’s AURA satellite, scientists determined 

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how chemical levels In the ozone hole, varied each year.

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With this new information, we can look into the future

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and say with confidence that ozone holes

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will be consistently smaller than 8 million square miles by 2040.

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And that will really be a milestone that 

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we’re finally past the era of big ozone holes.

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