In writing an abstract, it would be in Dr Greaves' interest not to make statements that make the whole look wacky. Based upon that choice of words, I would not read his paper.
Looking at it now, it appears that his introducer misquoted him.
He includes the term "altitude dependent gravity" in his paper, and while I think this is a bit of a waste of time to consider, it is a viable effect, compared with those of both the geoid and tides.