Yes, definitely! While today we often think of sustainability considerations as secondary, up-and-coming, or even fringe, at some point in the future (hopefully soon!) they will be a standard and even primary component of any business model.
In the same way, information technology and computer science were once secondary considerations - and today they are central (or even primary) elements of any successful business or organization.
So, I challenge you not to think about specializing your career towards a sustainability perspective. Rather, the first step is to figure this out:
I'm currently at the end of computer science bachelor and not quite sure what to do after.
What are you passionate about? What are you good at? What type of challenges do you enjoy solving? Find your skill set, and within that area, where do questions of sustainability apply? Any career path which you could imagine in the world today, will in the future require considerations of sustainability.
So, think of sustainability also on a personal level: what career choice will be sustainable for you? That is to say, what direction could you take your career that you will find fulfilling and challenging for years to come, so that you can continue to be as passionate about it years from now, as you are today? Bringing a sustainability perspective to something you are passionate about will bring about much more positive change in the world than trying to force yourself into a sustainability box that doesn't inspire you.
Something else to consider -- I took a few years to work after completing my BS before returning for an MS, and found that some experience out there in the "real world" helped focus my ambitions in grad school, and I've been able to get much more out of it than I believe I would have otherwise.