The sentence in which ethos is used for rhetorical appeal is "Saving the planet is a noble and worthwhile goal in itself".
Other sentences appeal to logos providing data about the benfits of recycling and how it has also become a big industry.
The ethos, on the other hand, relies on the ethical arguments and how recycling is a morally good practice. When you recycle you show that you care about nature and the preservation of the planet. Ethos comes from greek ethikos, and means moral, so arguments based on ethos will use morality to persuade the audience.