Its happening in the near future -- in a few thousands of years. Yes, that is near future considering the life of earth. However, this change doesn't happen over night once it begins, it takes several years for the flip to complete. You never know, probably it has already started. As of 2017, scientists doesn't know when the earth's magnetic pole flip happens and they don't know whether it has already been started. It would be a very feeble change in the first few months/years of the flip.
It is considered by the biological experts and scientists that the flip of the earth's mag poles has little impact on the known creatures on earth. Especially for human beings the effect is close to zero. Migrating birds can get affected in the beginning, but eventually they will adapt the change.