[great pollutions upon the face of the earth]: It is tempting to see this phrase as a prediction of modern air quality problems. That would be reading the word “pollutions” in its modern sense, and not the context in which it was meant. For instance, we have in the Bible:
Acts 15:20
20 But that we write unto them, that they abstain from pollutions of idols, and from fornication, and from things strangled, and from blood.
The pollutions are the evils of the idols, and the threat that one might become less clean and pure because of the contamination of those evils. This would be the context of pollutions in this verse in the Book of Mormon. There are great evils abroad. This context is confirmed by the definition of what they were: “murders, and robbing, and lying, and deceivings, and whoredoms, and all manner of abominations.”