Pretty easy, overall.
I took this class to fill my science without a lab, and it was very easy to pass. I am not a very science-y person, but the concepts were explained well and supplemented by the reading. We didn't follow the textbook, but in a way that made a lot of sense to me. There were no assignments, only 3 tests, one of which was the final that wasn't cumulative.
This was mainly geology basics - tectonic plates, types of rocks, volcanoes, etc. There wasn't much focus on the environmental impact, which is what I expected from the name of the course.
Hours per week:
Advice for students:
Go to the class. While you might be able to figure it out by just reading the book, the prof will not like you very much. Also, you only need the book if you're not planning on going to class. If you're going to lecture most of the time, don't buy it.