From the looks of it, it should literally have changed the face of Earth. And we see the face of Earth a couple of times in DS9, unchanged.
Doesn't really tell us much: the timetable of raising that new continent could have been decades or even centuries, and the project might still be perfectly on track. OTOH, it might
have been a paper project all along, make-work for idle scientists and engineers, impossible in practice for political, emotional and possibly also ecological reasons (although I'd think eco-engineering would have been the major challenge in such a project, and the primary driving force).