Answer:
Carbon dioxide raises Earth's temperature because it is a greenhouse gas. The greenhouse effect is basically when gases, like carbon dioxide, trap in heat from the sun that would usually be released back into space. Too many of these greenhouse gases traps in too much heat, which then creates problems like melting glaciers and even effects the migration of animals. But without these gases the Earth wouldn't be able to retain any heat so it wouldn't be suitable for life, therefore it is important to maintain a certain amount of greenhouse gases in the atmosphere.