Why is the Ozone layer so important?

no, the ozone does not affect temperature. What it does do, however, is absorb UV radiation. Without it, we would quickly sunburn. The ozone layer is created as charge particles from the solar wind enter the upper atmosphere and convert oxygen to ozone. A number of things cause it to shrink, mostly volcanoes, and possibly CFCs. The hole in the ozone layer that existed in the early 90s was caused by the Mayon eruption, a huge volcanic eruption in the Philippines., with the Unzen eruption (Japan) and the ongoing Pinatubo eruption (also in the Philippines) contributing.