The excerpt that best appeals to readers' pathos is:
"Yet every one of these disasters has actually happened somewhere, and many real communities have already suffered a substantial number of them. A grim specter has crept upon us almost unnoticed, and this imagined tragedy may easily become a stark reality we all shall know."
This passage evokes strong emotional responses by highlighting the real consequences of environmental neglect and the fear of impending disaster. The use of phrases like "grim specter" and "stark reality" creates a sense of urgency and concern for the potential loss that communities may face, tapping into readers' fears and concerns for their own environments and futures.