[Nyororin]

While I agree that it is unfortunate when it comes to scientific presentations, etc... That is no reason for it to be made a second language of Japan. Clearly, other countries out there are pulling it off without making English a second language.

I really see no justification other than simple selfishness.

I also don`t think that it would even be feasible if for some reason it did happen. I highly doubt that anyone in Japan is just going to switch over to speaking English simply because it has been designated as an "official" language. The world does not work quite like that...
If there were a significant subset of the Japanese population that spoke English as a first language, things would be different. But there is no such group. Most English speakers in Japan are transient - not even truly living in the country, let alone citizens.