After I got my PG (professional geologist) license, I started exploring other certifications. CPG? PG for other states nearby? When I asked other geologists at work, they didn't think those other certifications would do much for the organization or for me personally, so I dropped it.
There's been a backlash against certifications recently. For one, the sheer number of certifications seems to be multiplying. In the environmental biz, PG, PE (professional engineer), and some state-specific designations for environmental professionals have been around forever. Depending on what you work on, you may find other certifications such as CHMM to be useful. But new environmental management/science certs appear to be popping up everywhere - this website has about 20, making me suspicious that it's more of a certification mill than anything else. It's worth asking: what do these letters mean to anyone else? What roadblocks will they remove?
My sweetie (and the commentariat at AAM, although now I can't find an example) think that most certifications are just a useless obstacle to keep out new people and make sorting through résumés easier.
I don't think that's true for the PG. Getting a PG shows that a third party determined 1) my college/grad school transcripts showed that I passed a bunch of appropriate courses; 2) other people in the field are willing to vouch for me; and 3) I passed tests on general and professional knowledge. Those don't make me a great geologist automatically, but they do mean I've been confirmed to be at least minimally qualified. I'm also easy to find/check because I'm registered with the state. Finally, as a PG, I also have certain ethical requirements, and if I do something grossly unethical/incompetent, I can be hauled in front of a hearing board and my license removed.
That last bit can be pretty useful. If I'm encouraged/asked to do something that I'm not comfortable with, the PG gives me a backstop: "I will not jeopardize my license for this!" I haven't had to say this, but it's good to have the option available.
I'm focusing more on the science/writing/teaching stuff, so I don't foresee getting more regulatory or management-type certifications. But I'm open to certification-collecting if things do change.