Carson appeals to many of the rhetoric tools that Heinrich discusses such as pathos and logos, however in the end she establishes her credibility by using ethos. She begins her chapter with a quote that touches on the pathos aspect of her argument by showing the emotional side to the effects of mankind's work. As you continue to read you see how Carson has created a detailed analysis of how mankind has a had a strong effect on mother nature, thus she is using logos to give logical reasoning as to why we need to feel the emotion we do. In the end I believe Carson has established her credibility because she uses scientific sources to justify her logical argument, and despite her use of intellectual resources, she has also managed to appeal to her audiences emotional side long enough to make her audience want to listen to her argument.