One of the (many) problems with this article is the metaphor it uses to characterize what has happened. The flow change is called "river piracy" wording that more than implies what has occurred is an illicit activity. The reality we then learn is that the change returns the water flow to one which was in place three hundred or so years ago. So it is not "piracy" but one of nature's regular flip-flops. Accordingly from a science reporting perspective, I would guess that Globe readers would have wanted Ivan to interrogate the scientists as to whether there wasn't a less illicit and less charged image to express the change than "river piracy". 
Finally,  I would bet scientists would not say the change was "entirely" caused by human-induced climate change, but rather that that HICC was rather one of the significant driving factors.