It's certainly been discussed in the forums I've read, and it could certainly account for some of it, but the mid-season spike in home runs starting in 2015 see

It's certainly been discussed in the forums I've read, and it could certainly account for some of it, but the mid-season spike in home runs starting in 2015 seems to point to at least one additional factor that would be somewhat consistent across all ballparks (including climate controlled). The balls seem to be one of the only factors that would account for that.