The specific task you are assigned at an occupation. An example may be that you have a roofing job but your occupation is that of being a carpenter.
This is usually a broad title giving to a path you follow while working. An example may be you have an occupation of being a teacher but being a teacher at PVEC would be your job.
The new way of thinking of your career is that is your whole life, both work and the rest of your activities make up your career. So your career is no longer just what path you take when it comes to finding employment. But it could be your volunteer work, your creative pursuits, your community networks, all of it.