Career advice

I'm a student in environmental science. 3 classes away from M.S. degree. I took a post grad stats course and have since been filling my electives with Statistics courses.

currently have taken/taking:
Environmental Statistics
Intro to biostats

plan to take Experimental design as my last elective and possibly linear regression analysis.
if I did this it would put me 3 math electives and an internship from a second Masters in applied statistics.

I've considered doing a PhD in biostats but unsure if I will or not.

That said would you guys recommend going for the extra year for a dual masters? What career options would this allow? Any idea on the pay this combination could expect? My interests are in being actively involved in research though I have interests in many different areas but want to be useful and promote a better world for tomorrow by answering questions today. At a minimum I would want to be able to enter the workforce earning 60k per annum with potential for 100k+ later in career. I am 30 years old if that makes a difference for long-term career expectations.

Thanks for your input.