This claims not to be an April Fool's prank, but it has to be a little bit tongue in cheek. To earnestly make predictions based on assumptions about the world more than 500 years in the future implies at least a wink when coming from a serious scholar.

It reminds me of a claim I heard as a kid that I still think about today. This was a few years after Elvis died. It went something like "before his death in 1977, there were less than 100 Elvis impersonators in the world. By 1980, there were more than 10,000. If this trend continues, the entire biomass of the Earth will be composed of Elvis impersonators by the year 2000". This was obviously a joke, and is not even pointing out a fallacy relevant to the subject of the article, but I thought it was cute.