Question

About half of the forests that covered the earth in the early 1900s have been cut down. Discuss the impact this has on carbon dioxide levels in the atmosphere. Support your answer.

Answer 1

It has increased levels of carbon dioxide because trees take in carbon dioxide and put out oxygen. This means less tree equal less oxygen and more carbon dioxide because the trees wont be using it.

Answer 2

Since the vast amount of trees that can be located in a single forest can hold/process carbon dioxide once cut down there is no longer any space that can process this gas. 
Carbon dioxide in high levels can cut a hole in the atmosphere and evidence can be seen in a few studies.