You're in a delicate situation, since you'd be to blame for your co-workers potentially loosing their jobs. Nevertheless, doing nothing is also risky, since someone else from another department could show up and automate away your jobs leaving you in a hard place, and you won't have any control over that.

If you propose the automation yourself, and plan it's adoption within your team, you may have a chance of taking advantage of it, and even try to bring in more responsibilities within the company to your team to secure your teammates jobs.