Forces of Change
Atmosphere Protects

For billions of years, our atmosphere has been:

A shield against bombarding meteorites
A shade against destructive ultraviolet radiation
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.