If you plan to teach k-12 (particularly in a public school system) you will
need to have the art education background and hence certification in art ed.
If you have an opportunity to teach at a community college-certification is not
a requirement (although helpful to you personally) but they do require some
type of "acknowledgment of expertise." I strongly suggest the certification
route if you need benefits and looking for longevity. Good luck.
Kathy in Kalamazoo