For billions of years, our atmosphere has been:
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A shield against bombarding meteorites |
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A shade against destructive ultraviolet radiation |
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A blanket against the cold |
But human activity is altering two of our atmosphere’s protective duties.
1. |
The stratospheric ozone layer—the part of the atmosphere that protects us from the sun’s ultraviolet radiation—has deteriorated. |
2. |
The increasing level of “greenhouse gases” in the atmosphere is raising Earth’s temperature faster than at any time in the past. |