It’s a one-click unsubscribe right now. If you unsubscribe, you won’t receive further notifications for any certificate belonging to an account with the same email address. There’s currently no way to resubscribe either, short of using a different email address. (Some email providers like Gmail let you use something like youremail+someword@example.com as a way to get a new address without having to actually register a new account).
More fine-grained control over that process is planned at some point, e.g.:
Would something like “Note: Clicking this link will unsubscribe you from expiration notifications for all certificates associated with this email address.” work as an addition?