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[Music]

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ozone is the earth's natural sunscreen

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it screens ultraviolet radiation if

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there's less ozone more uv radiation

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gets to the earth

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if there's more ozone less uv radiation

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there are a few ingredients to the

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antarctic ozone hole the first

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ingredient is you have to have very high

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levels of chlorine and bromine in fact

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if you made a measurement now you'd find

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that about 80 percent of the chlorine

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over antarctica is from human produced

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the second ingredient is you have to

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have very cold temperatures over

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antarctica about 10 miles up or so it

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gets extremely cold and in those cold

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conditions you form fairly exotic clouds

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what we call polar stratospheric clouds

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and you will release this chlorine down

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there into a form that can destroy ozone

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[Music]

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the third ingredient is you need a

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little bit of sunlight the sunlight

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appears over antarctica in august

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september and just that little bit of

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light provides the energy to drive

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what's called the catalytic reaction in

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which one chlorine

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molecule

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can destroy thousands and thousands of

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ozone molecules until finally 100

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percent of the ozone in that layer from

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there is a question of how will

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climate change affect the antarctic

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ozone hole and in fact there's some

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questions about whether as it gets

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colder

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you can make the ozone hole last longer

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we don't have a good answer for that

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right now

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so we don't actually know what's going

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to happen so that's a real hot research

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topic

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our current predictions right now

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is that the ozone hole will be back to a

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level we saw in 1980 in the year of

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about 2070. for about the next 10 years

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or so we'll see very large ozone holes

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and then after about 2017 2018 in there

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they'll start getting smaller and