The stratosphere manages to absorb around 95% of the UV radiation that comes from the Sun. The stratosphere acts like a protective layer in our atmosphere for the living organisms on our planet. If the stratosphere was not able to absorb the UV radiation in that big of an amount and was letting through much more of it to reach the Earth, than life would be almost impossible on our planet, and most of the organisms would die out because the UV radiation will cause extremely big damage and lead to death.
