The document discusses the differences between the enhanced greenhouse effect and ozone depletion. The enhanced greenhouse effect is caused by human emissions of gases like carbon dioxide that strengthen the natural greenhouse effect and lead to increased global warming. In contrast, ozone depletion is caused by human emissions of CFCs and halons that damage the ozone layer and increase UV radiation reaching the Earth's surface. While greenhouse warming is a natural process, evidence shows current changes are unprecedented and not part of a natural cycle, but rather driven by human activities that add greenhouse gases to the atmosphere faster than natural processes can remove them.