If I were you I would take a hybrid route, focus on improving my programming skills to create a portfolio of projects using open data WHILE working on a graduate degree with an advanced mix of statistics and computer science.
Personally I wouldn't take a "Data Science" course, it's still "to novel" to tackle it as a full blown degree in academia. Instead I would focus on something related to the field you are interested in, while taking advantage of your backgroud. Something like a masters in bioinformatics/biostatistics focusing on sustainability issues.
ps: with the hybrid route you can graduate with (a) a portfolio proving hands-on experience and (b) academic credentials in your chosen application field.
