Did you just buy a sustainable mutual fund? No. The answer is no because human economies are still so far from real sustainability that even a highly idealized portfolio of our most sustainable enterprises necessarily still falls short. Ultimately, the best any portfolio can do is mirror the reality of the world, and today, still, even the best representatives of sustainability can be found wanting compared to what will be required if we would like to keep society thriving indefinitely. At best, whatever fund you just bought can only be described as, to a greater or lesser degree, more sustainable than its non-green counterparts.